Leica Geosystems

IPAS Pro IPAS CO+

User Manual

Leica Geosystems AG9435 Heerbrugg, Switzerland

Document Code: 754574

Document release: 2.0-2, 25-01-2010

This document shall not be reproduced in whole or in part without prior permission in writing from Leica Geosystems AG, 9435 Heerbrugg (Switzerland), either by mechanical, photographic, electronic, or other means (including conversion into or transmission in machine-readable form); stored in any retrieval system; used for any purpose other than that/ those for which it is intended; nor accessible or communicated in any form to any third party not expressly authorized by Leica Geosystems AG to have access thereto

Trademarks

Windows and Windows XP are registered trademarks of Microsoft Corporation

CompactFlash and CF are trademarks of SanDisk Corporation

Bluetooth is a registered trademark of Bluetooth SIG, Inc.

All other trademarks are the property of their respective owners.

International Warranty

The International Warranty can be downloaded from the Leica Geosystems home page at http://www.leica-geosystems.com/international warranty or received from your Leica Geosystems dealer.

Software License Agreement

This product contains software that is pre-installed on the product, or that is supplied to you on a data carrier medium, or that can be downloaded by you online pursuant to prior authorization from Leica Geosystems. Such software is protected by copyright and other laws and its use is defined and regulated by the Leica Geosystems Software License Agreement, which covers aspects such as, but not limited to, Scope of the License, Warranty, Intellectual Property Rights, Limitation of Liability, Exclusion of other Assurances, Governing Law and Place of Jurisdiction. Please make sure, that at any time you fully comply with the terms and conditions of the Leica Geosystems Software License Agreement.

Such agreement is provided together with all products and can also be found at the Leica Geosystems home page at http://www.leica-geosystems.com/swlicense or your Leica Geosystems dealer.

You must not install or use the software unless you have read and accepted the terms and conditions of the Leica Geosystems Software License Agreement. Installation or use of the software or any part thereof, is deemed to be an acceptance of all the terms and conditions of such license agreement. If you do not agree to all or some of the terms of such license agreement, you may not download, install or use the software and you must return the unused software together with its accompanying documentation and the purchase receipt to the dealer from whom you purchased the product within ten (10) days of purchase to obtain a full refund of the purchase price.

iii

Table of ContentsTable of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

Chapter 1

The IPAS System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Chapter 2

Installation and Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

License setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3License server setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Application machine setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Configuration of Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Chapter 3

Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Starting IPAS Pro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Launching IPAS Pro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Starting a New IPAS Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15The New Project Dialog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Chapter 4

IPAS Pro Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Processing Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Processing Options - IMU Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Processing Options - Using Pre-extracted Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Processing Options - GNSS Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Processing Options - Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

IPAS Pro Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Analyzing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Processed Data Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Raw Data Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Real-time Solution Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Residual Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Event Overlay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45Make Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Table of Contents

IPAS Proiv

Chapter 5

IPAS PPP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51IPAS PPP Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Background on precise orbit and precise clock corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

IPAS PPP Installation and Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Licensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

IPAS PPP Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54Step One: Data Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54Step Two: Data Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Step Three: Solution Plotting and Quality Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Step Four: Export ASCII solution file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

Chapter 6

IPAS CO+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

License Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Introduction to IPAS CO+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73

Misalignment Angle Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74Automated Misalignment Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74Misalignment Calculation with External AT Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Transform Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Point File Transform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Open and Save . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Appendix A

GNSS Input Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Appendix B

IPAS CO+ File Format Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95Camera Event File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95Photo ID File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95AT Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95IXYZOPK Format AT File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95ORIMA PATB AT File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96Output Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Appendix C

APM setting file Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101APM Settings File Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

1User Manual

Chapter 1

The IPAS System

Introduction IPAS (Inertial Position and Attitude System) is an integrated georeferencing system developed by Leica Geosystems AG. It rigorously integrates raw data from a high accuracy GNSS receiver with the raw data from an Inertial Measurement Unit (IMU) using a Kalman filter and outputs position, velocity and attitude data at a high rate.

The following figure illustrates the components of a IPAS20 System.

Figure 1-1: IPAS20 System Components

The following diagram illustrates the functional flow for the IPAS20 system:

The IPAS System

IPAS Pro2

IPAS Pro is a software package that post-processes IMU data together with GNSS data. It provides interfaces for the import and display of the raw data, the post-processing configuration setup, processing of GPS/IMU data, as well as the display and analysis of final computed solutions.

This manual describes how to use the IPAS Pro software.

Where to get assistance and training

Please be aware, that for a complete understanding of the functionality and operation of the system it is necessary to participate in a IPAS20 product training and maintenance course

For assistance and training courses please contact your local Leica Geosystems subsidiary or representative.

Headquarter

Internet http://www.leica-geosystems.com

Contact Leica Geosystems AGBusiness Unit Digital ImagingHeinrich-Wild-Strasse9435 HeerbruggSwitzerland

e-mail:info@leica-geosystems.comPhone: + 41 71 727 3131Fax: + 41 71 727 4674

3User Manual

Chapter 2

Installation and Configuration

System Requirements

IPAS Pro is a software package that runs under the Microsoft Windows family of operating systems. Basic system requirements are the following:

• IBM PC-compatible computer,

• Windows 2000 or XP Operating Systems,

• 128MB or greater RAM,

• 10GB or greater free disk space. Larger disk space is recommended.

Installation To install IPAS Pro software, double-click the setup.exe file on the IPAS Pro DVD. Follow the instruction provided by the installation program.

License setup

Introduction Starting from version 2.0 Leica IPAS Pro and IPAS CO use Leica Geosystems (LGS) FlexNet licensing.

Entitlements and Activation

With ordering a software product, customer gets an entitlement certificate with an Entitlement-Id.

The Entitlement-Id is the key to the license(s) of a product. It must be entered during the license activation at customer site.

For the license activation user’s computer must be connected to internet.

All issued licenses must be activated on the client license server computer. That means the target machine must be connected online to the FlexNet Operations (FNO) license server at Leica Geosystems through internet for getting the license. The license information is stored in a trusted storage on the client's computer.

For running the application program, there is no connection to FNO required.

Depending on the license model, a license can be returned to the license server FNO and re-hosted to another machine.

Re-hosting, as extended licensing functionality, is available only for registered customers.

Installation and Configuration

IPAS Pro4

Return to FNO function should be used also for expired evaluation licenses.

License Models

There are two major types of models - node-locked and floating licenses. Node-locked license model is used for a fixed license on a single computer, whereas floating license model is used for sharing licenses between different users. The number of concurrent users is defined by the number of available licenses.

IPAS software uses floating licenses.

License Checking

For checking a license, a running application program has to checkout / check-in the corresponding feature(s). The license is searched first in the local trusted storage at the application machine and then on the defined local license servers i.e. on the computer on which the user has activated the licenses by inserting the Entitlement Id(-s).

Application computers using floating licenses must stay connected online to a local license server.

The borrowing of a license (temporary transfer of a single license from the license server to a computer) allows the offline usage of the license for a given period of time. After use, it has to be returned to the floating server; otherwise it expires automatically after ending of the borrowing time.

For using floating licenses in a single computer environment the computer has to be set up for local license server and for application machine.

Licensing software

LGS FlexNet uses:

• on local license server - Client License Manager (CLM) Server SW - (clm_server_package.exe)

• on application machine - Leica License Manager (LLM) SW - (LLM_Installer.exe)

For using ERDAS FlexNet licenses ERDAS-FlexNet_Licensing.exe has to be installed to a local license server. IPAS ABS license, which is required for Leica IPAS CO+ functionality, uses Erdas FlexNet licensing.

License server setup License server is usually a server machine in the environment which serves the licenses to the application machines connected into company network.

It is also possible to use the floating license model if only one workstation is available - in that case this single workstation has to fulfill both functions - being license server and application machine.

License setup

5User Manual

1. Install clm_server_package.exe to the local license server. Follow the instruction provided by the installation program.

2. It is recommended to configure the license server for faster return of license features to the free pool with specifying the idle timeout time.

For this configuration step:

• Open the license server option file lgs.opt, located in the servers installation folder (usually C:\Program Files (x86)\Common Files\Leica Geosystems\License-Server\), in text editor.

• Add the line TIMEOUTALL 900 to specify the idle timeout for all features, returning it to the free pool for use by another user. 900 seconds is the minimum time system allows.

The license server option file lgs.opt should look as follows:

=====

DEBUGLOG lgs.log

NOLOG IN

TIMEOUTALL 900

=====

3. Open the CLM Admin Server SW and activate the licenses by entering the Entitlement Id.

For the license activation user’s local license server computer must be connected to internet.

Once the licenses have been activated the connection to internet is no longer required.

Installation and Configuration

IPAS Pro6

Figure 2-1: Enter Entitlement Id

Click ‘View Licenses in use’ in order to see the activated licenses.

Figure 2-2: View Licenses in use

License setup

7User Manual

Use ‘Return licenses’ function from ‘View Installed Licenses’ menu in case the rehosting of the licenses to another local license server is intended.

IPAS ABS license setup

IPAS ABS license, which is required for Leica IPAS CO+ Aerial Triangulation funtionality, uses Erdas FlexNet license server provided with ERDAS-FlexNet_Licensing.exe.

ERDAS-FlexNet_Licensing.exe has to be installed to the local license server.

Application machine setup

Application machine is the workstation with IPAS Pro installation.

1. Install the LLM_License_Installer.exe to the application machine. Follow the instruction provided by the installation program.

2. Open the LLM tool and go to ‘Config’ window for defining from which license server the LGS and ERDAS licenses are used. Browse to or type in the server name. Click ‘Add’ for adding the license server to the list. Click ‘Save’.

In case the whole setup is done with a single workstation and the application machine is acting also as license server then type in 'localhost'.

Figure 2-3: LLM Configuration

View Floating Licenses

After the configuration the licenses can be used at the application machine. Go to ‘Floating Licenses’ window and click ‘Refresh’ for viewing the available floating licenses from the listed license server(s).

Installation and Configuration

IPAS Pro8

Figure 2-4: View Floating Licenses

Node Locked Licenses

Leica IPAS Pro and IPAS CO use solely the Floating License model - thus handling of Node Locked Licenses is not the subject for IPAS software.

LLM offers ability to handle Node Locked Licenses.

In order to activate the Node Locked licenses go to ‘Node Locked Licenses’ window, enter the Entitlement ID and click ‘Activate’.

For the license activation user’s computer must be connected to internet.

Click ‘Refresh’ for viewing the available node lock licenses.

In order to Return the activated node lock license to FNO pick the license from the list and click ‘Return’. License Return operation requires internet access.

License setup

9User Manual

Figure 2-5: Node Locked Licenses

Borrow Floating Licenses

LLM tool allows to Borrow the Floating Licenses from the local license server in order to make the licenses available in application machine(s) for the cases when the network connection between the local server and the application machine will not be available.

Highlight in the list the license to be borrowed. Set the intended number of days and click ‘Borrow’.

License will be returned automatically once the number of the borrowing days has passed. User can return the license earlier by highlighting the borrowed license and clicking ‘Return’.

Application machine has to be connected to the local license server for Borrow and Return operation.

Installation and Configuration

IPAS Pro10

Figure 2-6: Borrow Floating Licenses

Configuration of Processor

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Configuration of Processor

IPAS Pro consists of two main parts: the user interface and the processor kernel. The location of the processor kernel is automatically specified during the IPAS Pro installation process. However it can be changed. To specify a different kernel location, select Tools -> Config Options from the IPAS Pro menu bar. The following dialog allows you to specify the location of the processor kernel.

This dialog also allows the user to specify the locations for IPAS CO and IPAS PPP processor.

Figure 2-7: Configuration Options

Installation and Configuration

IPAS Pro12

13User Manual

Chapter 3

Getting Started

Starting IPAS Pro This chapter provides you with concise descriptions of the functions and utilities of the IPAS Pro software and describes a general procedure used in the GPS/IMU processing.

Launching IPAS Pro

To start the program, double-click on the IPAS Pro icon or its shortcut. After the program is invoked, the splash screen is displayed:

Figure 3-1: The IPAS Pro Startup Splash Screen

The IPAS Pro splash screen closes in a few seconds and the Open Project dialog is displayed:

Getting Started

IPAS Pro14

Figure 3-2: The Open Project Dialog

The Project field of the dialog displays the location of your IPAS Pro project file. Click the Browse button to the right to navigate to the location of your project file.

The Recent Projects window displays the recent IPAS post processor projects that have been used. Up to five projects may be displayed. The projects that cannot be found anymore are displayed in red. If your project is not located in the recent project window, click the Browse button to navigate to it.

When a existing project is opened, if the directory path for any of the data files (IMU data file, GNSS data file, etc) is changed, then a dialog window will be displayed to prompt the user that the file does not exist in that directory as saved in the project file and try to detect whether it exists or not under the current directory where the project file is opened currently. Figure 3-3 shows an example where the IPAS Pro project was copied from Z:\IPAS20_TestData directory to E:\IPAS20_TestData directory. Any file which does not exist in any directory will be displayed in red color. Beside each file, a browse button allows the user to select individual directory for each file. The user can press Continue with Change button to continue so that all new project directory will be saved, or press Continue without Change so that the original directory structure will be maintained, or Cancel to go back to the IPAS Pro menu. This function allows the user to change all the project structure at one window when an entire project is copied into a new directory.

Starting a New IPAS Project

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Figure 3-3: The Project File Directory Change Dialog

The New button allows you to create a new IPAS Pro project. This is discussed in the Create A New Project section.

Starting a New IPAS Project

You can start a new project by clicking the New button on the Open Project dialog. The New Project dialog opens.

Figure 3-4: New Project Dialog

The New Project Dialog

The location of the IPAS Pro project file can be specified by clicking on the browse (...) button and navigating to the desired folder on your computer, or by typing the path of the project directly into the Project Name box. Click the Create button to create a new IPAS Pro project and open the IPAS Pro processing screen.

In the top left-hand corner of the IPAS Pro window, there is a toolbar with three icons.

Figure 3-5: Icons toolbar

Getting Started

IPAS Pro16

With this toolbar, you can create a New IPAS Pro project, Open an existing IPAS Pro project, and Save a current project. This toolbar can be accessed at any time when IPAS Pro is active.

17User Manual

Chapter 4

IPAS Pro ProcessingIPAS Pro uses rigorous Kalman filtering to determine the optimal solution for position, velocity and attitude of an airborne mapping and remote sensing vehicle using GNSS and IMU data. The quality of its solution relies heavily on the quality of the collected IMU and GNSS data. Before processing, the physical references such as the GNSS antenna lever arms and the gimbal frame to IMU reference frame lever arms should be known with great accuracy to reduce the possibility of errors in the processing.

Processing Options

After creating a new IPAS Pro post processor project, the following dialog opens. This dialog is the main processing area of the IPAS Pro post processor.

Figure 4-1: The IPAS Pro Processing Dialog

This is where you specify raw IMU and GPS data locations, processing options, start the processing, and invoke the plotting functions.

The Project field shows you the projects that are loaded and the location of the IPAS Pro project file.

Figure 4-2: The Project Field

IPAS Pro Processing

IPAS Pro18

It is a good practice to organize a project according to the following directory structure:

Project_Directory

... Extract - for extracted data

... Ground - for reference GNSS receiver data

... GNSS - for processed GNSS data

... Raw - for raw IPAS data

... Proc - for processed and final solution files

Processing Options - IMU Data

The Data fields allow you to specify the location of the IMU data file and GNSS data file.

Figure 4-3: Processing Options Data Field

In order for IPAS Pro to function properly, it requires the raw data files from the IPAS system as well as a post-processed GNSS solution file. Clicking the Raw Data button opens the IPAS Pro IMU Data Selection dialog.

Processing Options

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Figure 4-4: IPAS Pro IMU Data Selection Dialog

To specify the location of the raw data file, click the Data File browse button (...). Usually, the raw data is located in the <flight_name>/raw directory. Where <flight_name> is the name of the directory you create to contain all of the flight data.

To specify the location of the extracted files, click the Extract Directory browse button (...). A directory named extract is created automatically by IPAS Pro.

Click the Options button to open the IPAS Extract Options dialog. This dialog allows you to select the data to be extracted. If you intend to extract the real-time solution as well as raw measurements, check the RT GNSS solution and RT Navigation Solution check boxes.

Figure 4-5: IPAS Extract Options Dialog

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To start extracting, click on the Extract button. IPAS Pro reads the raw data file and extracts the data to the folder specified in the Extract Directory field. If the folder does not exist, it will be created automatically.

When extracting multiple raw data files, only the first file needs to be specified, IPAS Pro automatically moves to next files and extracts all raw data files in sequence.

A progress meter opens to inform you of the percentage completed during the extraction process.

Figure 4-6: Raw Data Extraction Progress meter

IPAS Pro informs you when the extraction is complete. The duration of the extraction process depends on the size of the GNSS/IMU data set and computer processing power.

IPAS Pro separates the raw data into up to several separate files. Each file corresponds to a different type of data. A brief description of each file is listed below:

• *.GMB Gimbal data collected during the mission,

• *.GPS GNSS data collected during the mission,

• *.IMU IMU data collected during the mission,

• *.TM User time file. This file is generated during the extraction process and specific to the Leica ADS40 Airborne Digital Camera system used to collect the imagery.

• *_*. Evt - Input Event File. Each input event will be stored in a separate event file. The file prefix will be the prefix from the raw data file name. For example, 20050624100053_FlightData_1.evt is the event file from channel one event.

• *_out_*.Evt - Output Event File. Each output event is also stored in a separate event file. The prefix of the file will be the prefix of the raw data file.

• *.RTG - Real-time GNSS solution file.

• *.RNV - Real-time GNSS/IMU integrated IPAS solution file.

• *.SUP - IPAS supplemental file where the all the lever arm information is stored.

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Figure 4-7: Extracted File Types

All messages are written into an extraction log file. During the extraction process, the integrity of the files, including their time gaps, is checked and reported in both the message window and the extraction log file.

The resultant file sizes depend on the length of each mission. Generally, *.RNV and *.IMU files are the largest of the four extracted files.

Once the extraction is complete, the IPAS Pro IMU Data Selection dialog looks like the following figure.

Figure 4-8: Completed IMU Data Selection Dialog After Extraction

The log window is constantly being updated as the extraction proceeds. This log window contains information regarding:

• extraction results,

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• system version,

• lever arms,

• IMU data file,

• GNSS data file,

• gimbal data file,

• TM file, and

• Gap checking for IMU data, gimbal data and raw GNSS data.

• Gap checking and repairing for TM file. If the gap is smaller than 50 milliseconds, then the gap will be repaired and additional TM records will be interpolated and fill the gaps. If the gap is larger than 50 milliseconds, then a error message will be displayed in the extract window and saved in the extract log file.

Clicking on Save returns you to the IPAS Pro Processing dialog. The file names used in this dialog are automatically saved into the project file.

Some settings in the raw data file, including lever arms, are automatically written to the configuration settings in the project file so that you only need to verify the lever arm values.

Processing Options - Using Pre-extracted Data

IPAS Pro also has the ability to allow you to use pre-extracted GNSS/IMU data in processing. The pre-extracted data must be based on the IPAS Pro extraction file formats and is not interchangeable with other GPS/IMU processing extraction formats.

To verify that your extraction file format is correct, select the file and then click the Check Files button.

The process for using pre-extracted data is very similar to processing raw data. To begin, click the Raw Data button on the IPAS Pro Processing dialog to open the IPAS Pro IMU Data Selection dialog. Locate the IMU button in the dialog:

Figure 4-9: IMU File Selection Portion of IMU Data Selection Dialog

Click on the IMU button and navigate to the location of the extracted IMU data. Once you have located it, click on the Open button to load the IMU data in IPAS Pro. IPAS Pro will automatically identify the corresponding gimbal file (*.GMB file) if it exists. It is important to note that the folder that contains the *.IMU file should also contain a *.GMB, *.GPS and *.TM file for the corresponding date and mission. Click on the Check Files button to ensure that the *.IMU file, *.GMB and *.GPS are files are free of error. Click the Done button to return to the main processing options.

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Processing Options - GNSS Data

Post-processed GNSS solutions are needed in order for IPAS Pro to produce accurate georeferenced results. Many kinds of post-processing software are available, but the software that you are using must be able to export the processed GNSS data to an ASCII file. IPAS Pro post processor requires the input post-processed GNSS file to be in a special format, which is defined in Appendix A “GNSS Input Format”. The IPAS Pro Processing dialog should look like the following:

Figure 4-10: IPAS Pro Processing Dialog After Raw Data Import

Click the GNSS button to open the IPAS Pro GNSS dialog:

Figure 4-11: IPAS Pro GNSS Dialog

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IPAS Pro allows you to launch your preferred GNSS processing software from within IPAS Pro. In order to do this, you must first select your preferred GNSS processing program by clicking on the browse button and navigating to the location of the executable file for your GNSS post processing software on your computer. Once this file is selected, click the Launch button to launch the GNSS post processor. For the purpose of this help file, GrafNav from NovAtel Inc. is used as the default GNSS Post-Processing software.

After completing the GNSS processing in GrafNav, a ASCII file is exported using the profile created by IPAS Pro. Select this ASCII file in the ASCII GNSS Solution File field and click on Import File button, this GNSS file will be converted into binary format file used by IPAS Pro and displayed in the IPAS Binary GNSS File field.

Precise Point Positioning (PPP) can also be used to process the GPS data when a reference receiver is not present. To start PPP, click on the Start button under the Precise Point Positioning, follow Chapter 5 for PPP processing. The PPP software will generate the binary GPS Solution file required by IPAS Pro automatically and display the file name in the IPAS Binary GPS File field.

After selecting the proper post-processed ASCII GNSS file, the window should appear similar to the following:

Figure 4-12: IPAS Pro GNSS Dialog After GNSS File Selection

Click the Import File button to convert the ASCII file into a binary file specific to the processing needs of IPAS Pro. A progress meter reports on the progress of the ASCII import.

Figure 4-13: GNSS ASCII File Import Progress Dialog

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Click the Close button to return to the IPAS Pro GNSS dialog. Click the OK button to finish the GNSS portion of the IPAS Pro project setup.

Processing Options - Processor

The processing of the GNSS and IMU data can commence once the raw IMU data and post-processed GNSS data have been loaded into IPAS Pro. A properly completed dialog should look similar to the following figure:

Figure 4-14: IPAS Pro Processing Dialog After Raw and GPS Data Imports

Click the Configure button to open the Processor Configuration dialog.

Figure 4-15: Processor Configuration Dialog

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This is the initial page that provides you with setup of the processor configuration. It is important to note the time ranges between the GNSS file and IMU file to ensure that each time range overlaps with one or the other. The time ranges are displayed in GPS week seconds after each file type to the right of the file name. The time range for IMU data has to lie within the time range of the GNSS data.

IPAS Pro will automatically process all data within GNSS and IMU data time window. However, user can change the data time. To set the processing time window, uncheck the All Data check box, and set the GPS week seconds into the corresponding edit boxes.

In this configuration page, you can also select a different output directory. The output format is IPAS Pro.

After the processing the File Converter Tool can be used in order to convert an IPAS Solution File into a SBET file or into an ASCII file, or convert a SBET file into an IPAS solution file or an ASCII file. Select Tools -> File Converter from the IPAS Pro menu bar to launch File Converter.

Figure 4-16: File Converter Tool Dialog

Processing Options - Processor - GNSS

Click the GNSS tab of the configuration dialog to verify the GNSS lever arm measurements.

Lever arm values are automatically extracted from the raw data file and written to the configuration settings in the project file.

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A lever arm can be defined as the three dimensional coordinates of a point with respect to a coordinate frame. In IPAS Pro, all lever arms are measured in the reference frame. The referece frame is usually defined by the mapping or remote sensing unit. For example, with the ADS40, a reference frame is defined with the PAV30 mount, with the origin of the reference frame at the PAV30 center while x-axis points to forward, z-axis points downward and y-axis points to right to form a right-hand coordinate system. Usually two lever arms are required to measure in the field when IPAS10 is istalled, one is the GNSS antenna while the other one is the IMU center. Those values are measured during the installation and entered into the IPAS10 system through the IPAS Controller. A field technician should verify the lever arm values whenever there is a change of installation related to reference sensor, IMU, or GNSS antenna.

For each set of flight data to be processed, the values of the lever arms should be verified against the published values provided by the hardware installer or system operator.

Figure 4-17: GNSS Lever Arm Dialog

This dialog is used to verify and correct, if necessary, the GNSS lever arm in the reference frame. As illustrated in the above figure, the lever arm values are measured along the x, y, and z axes of the reference frame from the center of the reference frame to the GNSS antenna phase center.

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Processing Options - Processor - IMU

Click the IMU tab to enter the IMU lever arm and boresight measurements.

Figure 4-18: IMU settings Dialog

This configuration page is where you verify and correct, if necessary, the IMU lever arm and boresight angle measurements. As illustrated in the above figure, the IMU lever arm is measured along the x, y, and z axes of the reference frame from the center of reference frame to the IMU center. The boresight angles are also measured as the rotation angles of IMU body frame relative to the reference frame.

IMU Latency value gets detected automatically according to the IPAS system IMU type and is shown in the IMU Latency window as grayed out. Editing of the latency value is normally not required.

When a NUS5 IMU is detected, a data filter list box is displayed. A default filter file is supplied with IPAS Pro to use with all NUS5 systems. The other options for the user would be to select ‘Do not Apply Filter’ or ‘Browse for Filter File’. Leica Geosystems support provides the specific filter files only for the certain NUS5 IMU-s.

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Processing Options - Processor - Aircraft

Click the Aircraft tab to enter the aircraft boresight settings.

Figure 4-19: Aircraft Frame settings Dialog

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Processing Options - Processor - Advanced

Click the Advanced tab to enter the advanced processing settings.

Figure 4-20: Advanced settings Dialog

Three types of attitude initialization approaches can be selected from this page:

• Use Static/In-Motion Alignment. This is the default approach. IPAS Pro will automatically compute the initial roll, pitch and heading.

• Use real-time Solution. Attitude computed from real-time IPAS solution are used to intialize the IPAS Pro Kalman filtering.

• User Input Attitude. User can set initial roll, pitch and heading at a specified GPS week seconds. IPAS Pro will start the Kalman filter based on this initial setting.

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IPAS Pro Processing

Once setup is completed, click the GO button to open the Start Processing dialog. The Start Processing dialog allows you to verify that the incorporated GNSS/IMU data is correct and that their time windows overlap.

Figure 4-21: Start Processing Dialog

Click the Output File browse button to specify the location of the output file. By default, all overlapped data is processed. However, you can also specify different start time and end time in GPS week seconds. IPAS Pro will not function properly if the Data Time period does not lie within the time ranges of the GNSS and IMU data sets. Click the Start button to begin processing. A progress meter displays the progress of the job as well as the estimated time of completion.

Figure 4-22: Processing Progress Dialog

Click the >>> button to open the Log window which provides a detailed description of the state of the current progress. Click the <<< button to close the Log window.

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Figure 4-23: Expanded Processing Progress Dialog

Once processing is finished, the progress meter looks like this:

Figure 4-24: Finished Processing Progress Dialog

Click the Done button to close the dialog and return to the main IPAS Pro post processor processing dialog. IPAS Pro post processor outputs the processing files into the proc sub-directory under the project directory by default.

In the process log window, the statistics of estimated IMU accelerometer biases, accelerometer scale factor, and gyro bias errors, gyro scale factor are listed at the end of the processing. The statistics of estimated position residuals are also dislayed in the log window. The original lever arm values and the estimated lever arm value are output there as well.

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Those values are listed in the processing log file for further analysis. A example for this section of log file is given in the following figure.

Figure 4-25: Example of the Portion of Log File with Error Statistics

To analysis more on the statistics of the position residuals and the lever arm values, please refer to the Residual Analysis under Analyzing Data section.

With respect to the statistics of the estimated IMU sensor errors, including accelerometer biases, accelerometer scale factor errors, gyro biases and gyro scale factor errors, these values shall be evaluated against the threshold listed in the following table for each type of IMU used to acquire this dataset. If the estimate IMU sensor error values are larger than the specifications, then other aspects of the processing results, including the residual errors, measurement rejections shall be analysd. If this situation repeatly happens to one system, Leica support shall be contacted and IMU health shall be analysed by Leica support.

Table 4-1: Threshold of IMU Sensor Errors

iIMU-FSAS LN-200 33BM61 MicroIRS

Gyro bias (deg/h) 3.0 2.0 5.0 0.25

Gyro scale factor error (PPM)

1000 1000 500 100

Accelerometer bias (μg)

1000 1000 500 200

Accelerometer scale factor error (PPM)

1000 1000 500 300

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Note: Only if the estimated IMU sensor errors repeatedly exceeds the specified thresholds, and all other quality analysis are passed, then the IMU health shall be checked. If the estimated IMU sensor errors exceeds the threshold for only one dataset, that can be caused by other factor, and it does not necessarily mean that the IMU is not healthy.

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Analyzing Data Post processing analysis is very important in GNSS/IMU processing because it allows you to visually view and analyze the raw data and processed results. The following data can be visually plotted:

• raw IMU data,

• real-time GNSS and GNSS/IMU solutions,

• processed GNSS Data,

• processed results from IPAS Pro post processor,

• gimbal data - view and assess the processed position, velocity, attitude, and corresponding accuracies.

The processed results can also be compared against each other and their differences can be plotted. Plots are accessed by clicking the Graphs button in the Analyze section of the IPAS Pro Processing dialog.

Processed Data Plots This portion of the plot shows the processed results and their corresponding standard deviations. These plots may be viewed from several different perspectives thus allowing you to thoroughly analyze the quality of the results.

If the graph dialog is invoked from a processed project, then the processed result from that project is loaded with the North-East plot displayed by default.

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Figure 4-26: Available Processed Data Plots

You can zoom in and out of each plot by dragging a box around the desired area using the left mouse button. Click the right mouse button to return the view to the general overview.

Those plots with auxiliary standard deviation (SD) plots support synchronized zooming. For example, zooming in the Roll plot automatically zooms to the corresponding area (with respect to time) in the Roll SD plot.

Any IPAS Pro file can be loaded for plotting by clicking the Result File button. Once the file is specified, it is loaded automatically and displayed with the North-East plot by default.

The following plots are available for the IPAS Pro processed results:

• North-East: North and East plot, corresponding to vehicle trajectory,

• North-Elevation: North and elevation plot,

• East-Elevation: East and elevation plot,

• Elevation-Time: Elevation versus GPS Time in week seconds,

• Roll-Time: Roll versus GPS Time,

• Pitch-Time: Pitch versus GPS Time,

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• Heading-Time: Heading verus GPS Time,

• X velocity-Time: North velocity versus GPS Time,

• Y velocity-Time: East Velocity versus GPS Time,

• Z velocity-Time: Vertical velocity versus GPS Time.

Raw Data Plots Click the Raw Data tab on the left side of the dialog to display the options for plotting raw IMU, GPS and Gimbal data as shown in the following figure:

Figure 4-27: Plot Selection Window

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IMU Raw data

Click on X Gyro Rate, Y Gyro Rate, or Z Gyro Rate to display the raw gyro data in degrees/second.

Figure 4-28: X Gyro Rate Versus GPS Time

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Click on the X Acceleration Rate, Y Acceleration Rate, or Z Acceleration Rate to display the raw accelerometer data in meter/second2. The following is an example of X acceleration rate.

Figure 4-29: X Acceleration Rate Versus GPS Time

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GNSS data

On the GNSS file tab, following plots can be viewed:

• North-East Latitude-Longitude 2D trajectory plot,

• North-Elevation Latitude-Height profile,

• East-Elevation Longitude-Height profile,

• Elevation-Time Elevation profile versus GPS Time,

• X Velocity - Time North velocity versus GPS Time,

• Y Velocity - Time East velocity versus GPS Time,

• Z Velocity - Time Up velocity versus GPS Time.

The following figure is the North-East plot which shows the 2D trajectory.

Figure 4-30: Latitude and Longitude Plot and Their Standard Deviations

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Gimbal Raw data

Under the Gimbal file tab, the following plots can be viewed:

• Roll - Time Roll gimbal value versus GPS Time,

• Pitch - Time Pitch gimbal value versus GPS Time,

• Heading - Time Heading gimbal value versus GPS Time.

The following figure is a plot of roll gimbal value versus GPS time.

Figure 4-31: Roll Gimbal Value Versus GPS time

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Real-time Solution Plots

Click on the Real-Time Data tab on the left side of the dialog to display the options for plotting real-time GNSS solution and real-time GNSS/IMU solution plots.

The following plots are available for real-time GNSS solution:

• North-East Latitude-Longitude 2D trajectory plot,

• North-Elevation Latitude-Height profile,

• East-Elevation Longitude-Height profile,

• Elevation-Time Elevation profile versus GPS Time,

• X Velocity - Time North velocity versus GPS Time,

• Y Velocity - Time East velocity versus GPS Time,

• Z Velocity - Time Up velocity versus GPS Time.

The following plots are available for real-time GNSS/IMU Solution:

• North-East: North and East plot, corresponding to vehicle trajectory,

• North-Elevation: North and elevation plot,

• East-Elevation: North and elevation plot,

• Elevation-Time: Elevation versus GPS Time in week seconds,

• Roll-Time: Roll versus GPS Time,

• Pitch-Time: Pitch versus GPS Time,

• Heading-Time: Heading verus GPS Time,

• X velocity-Time: North velocity versus GPS time,

• Y velocity-Time: East Velocity versus GPS time,

• Z velocity-Time: Vertical velocity versus GPS time.

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Residual Analysis This function allows you to plot the estimated level arm value as well as the measurement residual error as estimated by the Kalman filter. The following information can be plotted from this selection:

• GNSS Lever Arm X GNSS antenna lever arm in x-axis,

• GNSS Lever Arm Y GNSS antenna lever arm in y-axis,

• GNSS Lever Arm Z GNSS antenna lever arm in z-axis,

• Position Residual X Estimated residual for GNSS solution in x-axis (latitude) together with the input standard deviation,

• Position Residual Y Estimated residual for GNSS solution in y-axis (longitude) together with the input standard deviation,

• Position Residual Z Estimated residual for GNSS solution in z-axis (height) together with the input standard deviation.

The following figure demonstrates the input and the estimated lever arm values. The blue line is the estimated lever arm value while the green line is the input lever arm value. The input lever arm is always a constant value. The estimated value is usually a constant as well. If the estimated lever arm is not a constant, it usually indicates that there may be issues with this data which needs further investigation.

If the input lever arm is significant different from the true lever arm, it may take a few iterations before IPAS Pro can converge to the correct lever arm values. In this case, the estimated lever arm values should be used as the input values and IPAS Pro processing should be repeated.

Note: If lever arm estimation is intended, a trajectory pattern for calibration shall be flown.

Figure 4-32: Estimated X Lever Arm

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The following figure plots position residuals estimated from Kalman filter. The blue line shows the residuals from GNSS solution while the green lines show the positive and negative one-sigma standard deviation values of the input GNSS solution. In general, the residuals shall be within the bounds of the standard deviations. If the residuals go out of bounds of the standard deviation, it usually indicates there are issues with the data set which requires further investigations. Possible causes are input lever arm values are significantly wrong, IMU data gaps, GNSS data gaps, quality issue from GNSS solution, wrong configuration parameters, IMU out of specifications etc.

Figure 4-33: Estimated Position Residual in Y axis

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Event Overlay IPAS Pro plot function allows you to overlay the evenet mark on the trajectory and other plots. Check the Event check box as shown in the following figure, click on the Event File button to browse the event id file (*.evt file) created during the extraction process. Each event will be displayed on the plot as a gray dot. Check the Show Id check box will display the event ID name on the plot as the same time.

Figure 4-34: Events Overlayed on the Trajectory

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Figure 4-35: Events with ID name Overlayed on the Trajectory

,

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Make Differences This function allows you to compare two solution files between different runs of IPAS Pro processing, or between a IPAS Pro solution file and a current ADS40/ALS50 solution file, or between IPAS real-time solution file and IPAS Pro solution file.

Click the Compare Data button to display the options to make a difference file or to plot a difference file.

Figure 4-36: Compare Data Options

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Create A Difference file

If a difference file does not exist, then you can make a new one by clicking on the Make File button to open the Make Difference Plot File dialog:

Figure 4-37: Make Difference Plot File

Use the browse buttons (...) to select a source file and destination file. The source file can be in IPAS Pro output format or in SBET output format. Once the files are specified, click the Make File button to make the difference file. The destination file is created with IPAS calculated differences between the two solution files.

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Plot Difference File

Once the difference file is made, it is automatically loaded and the north differences are displayed by default. You can view another difference file by clicking on Difference File and loading the file.

The following differences can be viewed:

• dNorth Latitude differences,

• dEast Longitude differences,

• dElevation Height differences,

• dRoll Roll differences,

• dPitch Pitch differences,

• dHeading Heading differences,

• dXVelocity North velocity differences,

• dYVelocity East velocity differences,

• dZVelocity Upward velocity differences.

The following figure shows a difference in latitude direction between two IPAS solution files.

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Figure 4-38: Latitude Differences Between an IPAS Pro Solution File and a Real-time Solution File

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Chapter 5

IPAS PPPIPAS PPP, which stands for Inertial Position and Attitude System (IPAS) Precise Point Positioning (PPP), is a post-processing software package developed by Leica Geosystems AG for high accuracy position and velocity determination using data from a single Global Positioning System (GPS) receiver.

IPAS PPP Introduction

Through the processing of GPS satellite signals, along with precise satellite orbit (hereinafter called precise orbit or just called orbit) and precise satellite clock corrections (hereinafter called precise clock or just called clock) information, the IPAS PPP software can produce high accuracy position and velocity results for kinematic objects using the observations from a single GPS receiver. The most advantageous aspects of using this product are: (1) eliminating the requirement of a reference receiver, as in traditional double-differencing positioning technique, (2) producing high accuracy position and velocity solutions and (3) the use of this product is straightforward, requiring minimum user interaction and a priori experience.

In order to obtain the best position and velocity accuracy for which this product has been developed, several prerequisites should be met:

(1) Geodetic-grade dual-frequency GPS receiver and antenna should be used to collect the observation data. Doppler observations are required in order to obtain velocity solution in addition to the position solution.

(2) Precise orbit and precise satellite clock information should be supplied when running this software. High-rate (e.g. 30-second interval) satellite clock corrections is preferred to low-rate ones (e.g. 5-minute interval). The IPAS PPP software can retrieve this data for the user.

(3) GPS observation data should be continuously collected for a long enough period of duration. The recommended minimum observation period is 60 minutes. In addition, it is suggested that the GPS signal tracking cutoff angle shall be set to smaller than 5 degrees.

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Background on precise orbit and precise clock corrections

International GNSS (Global Navigation Satellite System) Service (IGS) offers two products, namely precise orbit data and precise clock correction data, to the GNSS community for better position and navigation accuracy. The typical names for precise orbit and precise clock correction files are "igswwwwd.sp3.Z" (or igswwww.sp3c.Z if the precise orbit file is in sp3c format) and "igswwwwd.clk.Z", respectively, where "igs" represents the agency that generates the product files, "wwww" represents the 4-digital GPS week number and the "d" represents the day in the GPS week and ".Z" is the suffix of a compressed file. The interval of the precise orbit data is usually 15 minutes while the interval for precise clock correction data is 5 minutes.

The IGS provides different categories of products based on the product's availability latency. One category is the FINAL product, which has a latency of about 13 days after the GPS observation. Another is the RAPID product, which has a latency of about 17 hours after the GPS observation. To distinguish the RAPID products from the FINAL product, the IGS uses the names "igrwwwwd.sp3.Z (or igrwwwwd.sp3c.Z) for precise orbit file and "igrwwwwd.clk.Z" for precise clock file. Both categories of products have same format except their different latencies and accuracies. FINAL category products generally have better accuracy and reliability than the RAPID ones.

To use the FINAL category products in IPAS PPP for the best accuracy, it is advised to plan your flight missions in advance to make sure that you collect the mission data at least 13 days before your project deadline.

Under the organization of International GNSS Service, there are several data analysis centers, such as Jet Propulsion Laboratory (JPL), Center for Orbit Determination in Europe (CODE), National Geodetic Survey (NGS), etc. These analysis centers also generate their own precise orbit and precise clock corrections products. The products from those analysis centers have the same format as the IGS products. However, some analysis centers, such as JPL and CODE, produce precise clock corrections at a higher rate (30-second interval) than the IGS ones (5-minute interval). IPAS PPP recommends the use of high-rate precise clock data files whenever possible. Unlike the IGS organization, the individual data analysis centers do not generate RAPID category precise orbit (clock) data files. They produce precise orbit and precise clock corrections data only in FINAL category.

NOTE: In order to produce consistent IPAS PPP solutions, the precise orbit and precise clock corrections used for GPS data processing should come from the same agency.

For example, if the precise clock corrections data are generated by JPL, the precise orbit data used for IPAS PPP should also come from JPL. The name convention for the data analysis centers' products is quite similar to the IGS products. For example, JPL products usually have file names as "jpl13984.sp3.Z or jpl13984.sp3c.Z" and "jpl13984.clk.Z" for the precise orbit and precise clock correction files, respectively.

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IPAS PPP Installation and Configuration

System Requirements IPAS PPP is a software package that runs on a PC with Microsoft Windows family of operating systems. Basic system requirements are:

• IBM PC-compatible computer,

• Windows 2000 or XP Operating Systems,

• 128MB or greater RAM,

• 100 MB or greater free disk space. Larger disk space is recommended.

Installation IPAS PPP can be installed separately or installed together with IPAS Pro. When IPAS PPP is installed together with IPAS Pro, please follow the IPAS Pro installation procedure and no additional installation for the IPAS PPP is required. When IPAS PPP is installed separately, the followings steps should be followed:

• Locate the installation file "IPAS_PPP.EXE"

• Double-click on the installation file, following the subsequent installation instructions.

Once IPAS PPP is installed, it can be started under "Program Files\Leica Geosystems\IPAS PPP".

Licensing A license is required to run IPAS PPP. A USB dongle that contains the license information will be provided to the users by Leica Geosystems.

NOTE: In order for the USB dongle to work properly with IPAS PPP software, a SafeNet USB SuperPro/UltraPro driver Version 7.3.0.0 or higher is required.

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IPAS PPP Processing

The use of IPAS PPP software consists of three steps, namely Data Preparation, Data Processing and Solution Plotting with Quality Check. The first step is to prepare the GPS observation data file and precise orbit and precise satellite clock correction data files. The GPS observation data file can be in either NovAtel raw (BINARY) format or RINEX (ASCII) format. If last letter of the GPS data file name is capital 'O' or small case 'o', IPAS PPP will regard the GPS observation data file is in RINEX format. Otherwise, the GPS data file is considered as in NovAtel raw (BINARY) format. The second step is to execute the data processing and obtain position and velocity results. The third step is to plot the IPAS PPP results and check the quality of the results. IPAS PPP also provides a feature to allow the users to convert IPAS GPS solutions to an ASCII format.

Step One: Data Preparation

Once the IPAS PPP software is started, a user interface will be presented with a main program window as shown in Figure 5-1: “IPAS PPP User Interface” .

Figure 5-1: IPAS PPP User Interface

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The data preparation can be described in the following steps:

• Preparing the GPS data file. Clicking on the Data tab, the users will see the screen that asks the users to specify the location of the GPS data file. When IPAS PPP is used together with IPAS Pro, this GPS data file name will be automatically extracted from the IPAS Pro project file. In the example as shown in Figure 5-2: “Loading GPS data file to IPAS PPP” the GPS file is "20061026_010813_rover_raw.GPS" and it is stored under the directory "D:/My_Project". This file is in NovAtel raw binary format since its last letter in the file name is "S" not "O" or "o", which indicates RINEX file format is used. Once the file is loaded, the information on the observation starting and ending time will be displayed in the format of GPS week seconds, GPS week number, and the day of the week. In this example, the GPS data collection started at GPS second 349694 in the GPS Week 1398. The Day of Week (DoW) of the starting time is 4 (ie. Thursday in the GPS Week 1398). The GPS data collection stopped at GPS second 356284 in the GPS Week 1398. The Day of Week of the stopping time is 4 (ie. Thursday of the GPS Week 1398). Please note that the GPS second counts from 0 at each week's Sunday 00h:00m:00s.Input the camera event offset time if there is any.

Figure 5-2: Loading GPS data file to IPAS PPP

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• Preparing the precise orbit and precise clock files. The precise orbit and precise clock files can be directly imported to IPAS PPP software at this step, if both files are already available in your computer - this means, in case both files have previously been downloaded from the internet or obtained from somewhere else.

Figure 5-3: Loading precise orbit and precise clock data files to IPAS PPP

In most cases, however, the users do not have the precise orbit or precise satellite clock files. In this case, IPAS PPP will help the users automatically download both files from ftp sites. First, pull down the arrow to select one from the multiple ftp sites, as indicated in Figure 5-4: “Select the internet source of precise orbit and precise clock data files” . In this example, the IGS ftp site is selected.

NOTE: Internet connection must be available at the computer in order to download the precise orbit and precise clock correction files from the ftp sites. Both precise orbit and precise clock files can be downloaded from a number of ftp sites for free.

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Figure 5-4: Select the internet source of precise orbit and precise clock data files

It is recommended that precise orbit and clock files from CDDIS ftp site be used whenever available since this site provides precise clock file with 30 seconds interval.

Click the Check Ephemeris Availability button to check what types of precise orbit and precise clock data are available from the particular ftp site that you have just selected. The IPAS PPP will link to that ftp site and check the availabilities for you. As shown in Figure 5-5: “Check the availability and select one type of precise data files” , two types of precise orbits and clocks are available: final orbit (clock) and rapid orbit (clock), at the IGS ftp site for the date corresponding to the GPS data given in Step Preparing the GPS data file. By default, the IPAS PPP automatically selects the final orbit and clock files, because the final precise data have higher accuracies than the rapid data. In this example, the final category of orbit (clock) data files, e.g. igs13984.sp3.Z and igs13984.clk.Z, is selected. If the users do not select the IGS final category precise orbit (clock) data files, they may select another type of precise orbit and precise clock data files. In this example, the users may choose IGS rapid category precise orbit (clock) data files (in this example "igr13984.sp3.Z" and "igr13984.clk.Z, respectively).

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To eliminate the possibility of using different categories precise data files in the data processing, it is recommended to select only one category of precise data files at one time. It is highly recommended that the same type of precise orbit and precise clock data files should be selected. It is always NOT recommended to use mixed type of precise orbit and precise clock data files, e.g. mix final orbit data file with rapid clock data file.

NOTE: The rapid orbit will be available 17 hours after the time of data collection. The final orbit and clock are available 13 days after the data collection.

Figure 5-5: Check the availability and select one type of precise data files

Click the Download button to download both files to the specified directory, after the type of the precise orbit and precise clock data is selected. Under the directory where the GPS file is stored, IPAS PPP automatically creates a directory called "PPP", if it does not exist. The downloaded precise orbit and clock files are stored to the "PPP" directory. In this example, the directory where the GPS file is stored is "D:/My_Project", thus the precise orbit and precise clock data files are stored to "D:/My_Project/PPP". If the downloaded files are in compressed format, they will be automatically uncompressed. Both precise orbit and precise clock files are automatically imported into IPAS PPP after they are successfully downloaded, as shown in Figure 5-6: “Download and import precise data files to IPAS PPP” .

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Figure 5-6: Download and import precise data files to IPAS PPP

After the orbit and clock files are imported, their time span information is extracted and displayed. Make sure the time span covers the time span of the GPS observation data. At this stage GPS data, precise orbit data and precise clock data have all been prepared for IPAS PPP processing. Go to Step Two: Data Processing to continue the processing.

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Step Two: Data Processing

By clicking the Process tab, as shown in Figure 5-7: “Process GPS data using IPAS PPP” , the users can start to process the GPS data using IPAS PPP.

Figure 5-7: Process GPS data using IPAS PPP

In the top panel of the screen, a summary of the basic information such as GPS data file name, precise orbit file name, precise clock file name, the start date & time (hereinafter, time always means the seconds in week in GPS time system, unless specifically stated otherwise) and end date & time of each data file are displayed. In this example, the GPS file name is "20061026_010813_rover_raw.GPS", the precise orbit file name is "igs13984.sp3", and the precise clock file name is "igs13984.clk". The start time and end time for GPS data are 349694 seconds and 356284 seconds, respectively. The start time and end time for precise orbit data are 345600 seconds and 431100 seconds, respectively. The precise clock file has the same start time and end time as the precise orbit file. The date for all the three data files is the 4th day of GPS week 1398.

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In the middle panel, there are several options available for user to modify, although the modification is not necessary in most cases.

The first option is the initial coordinate of the GPS receiver. By default, this information is automatically extracted from the GPS data. If the users want to change it, the new values can be entered here. The latitude and longitude are in the format of degree, minute, second. The sign convention for latitude and longitude is that latitude north and longitude east are "+" and that latitude south and longitude west are "-". The unit of height is in meters.

The second option is the start time and end time for processing. By default, the entire GPS data set is processed. If only a portion of the GPS data set rather than the entire data set needs to be processed, the users can specify the start time and end time. The user specified time should not exceed the time span of the GPS data its own.

It is highly recommended that the users process the entire GPS data set in order to achieve the highest possible position and velocity accuracy.

The third option that users can modify is the path and name of the IPAS PPP output file. By default, the output file has the same file name as the GPS data except that its extension is .ppp. The output file is stored by default under the PPP directory.

Clicking on the Start Processing PPP button will start the IPAS PPP processing once all the options are gone through. If the project has not been saved, a window will come up to prompt the users to enter the IPAS PPP project file name, as shown in Figure 5-8: “Save IPAS PPP project information” . If IPAS PPP is started from IPAS Pro, then the IPAS Pro project file will include the IPAS PPP project information. In this case, no window will pop up to ask for the IPAS PPP project name. After the users enter the IPAS PPP project file name and click the Save button, all the information such as: GPS data file name, precise orbit file name, precise clock file name, initial coordinates of the GPS receiver will be saved to the project file.

Figure 5-8: Save IPAS PPP project information

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Meanwhile, the IPAS PPP data processing will start, as indicated in Figure 5-9: “Progress of IPAS PPP data processing” . The GPS data will be processed until it is finished. The data processing can be terminated by clicking the Stop Job button.

Figure 5-9: Progress of IPAS PPP data processing

IPAS PPP processing consists of forward processing, backward processing and refined processing. During these steps, a progress bar indicates the percentage of the data processing which has been completed. If there are important messages, then these will be displayed in the Log window. Log window can be activated by clicking ">>>" button. The log window can be deactivated by clicking on "<<<" button.

Once the data processing is completed, The Stop Job button will automatically change to Done button. The user shall go to 3.3 Step Three to plot the solutions and to check the quality of the IPAS PPP solutions.

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Step Three: Solution Plotting and Quality Check

The checking of the quality of IPAS PPP solution is an important step in the use of the software. In order to make sure the IPAS PPP produces high quality solutions, the users are suggested to check several quality indicators by looking at the graphical plots or examining the numerical results after processing the GPS data. By clicking the Plot Results button as shown in Figure 5-10: “Start quality check” , the users can start the quality check procedure.

Figure 5-10: Start quality check

Specifically, the following steps should be checked:

1. Check the differences between backward and forward solutions

The users plot the differences between the backward and forward solutions for latitude, longitude and height components. Normally, the horizontal differences between backward and forward solutions should be bounded within 0.20 m during the entire period of observation time. Generally, the vertical differences between backward and forward solutions should be within 0.30 m during the entire period of observation time.

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Shown in Figure 5-11: “Differences between backward and forward solutions” are the backward and forward differences for the example data in this manual. In the figure, the x-axis is GPS time in unit of week seconds and the y-axis is the differences for latitude, longitude and height components in unit of meters. The corresponding standard deviations and RMS of the differences are displayed on the bottom of the plot.

Figure 5-11: Differences between backward and forward solutions

2. Check the statistics of the differences between backward and forward solutions

Generally, both the standard deviation (1 sigma) and root-mean-squares (RMS) for horizontal component should be at the level of less than 0.10 m. For vertical component, both the standard deviation (1 sigma) and root-mean-squares (RMS) should be at the level of less than 0.15 m. The three-dimensional standard deviation (1 sigma) and root-mean-squares (RMS) should be less than 0.20 m. For the example data, the statistics of the differences are shown in Table 5-1: “Statistics of the differences”

Table 5-1: Statistics of the differences

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3. Check the Backward and Forward Zenith Tropospheric Delay Estimate

The differences between the backward and forward zenith tropospheric delays generally are very small during the entire observation period. The maximum magnitude of the differences is normally about a few centimeters. Under exceptional circumstances, this maximum magnitude might be as large as 0.08 m. The standard deviation and RMS of the differences generally should not exceed 0.02 m.

For the example data of this manual, the differences between forward and backward zenith tropospheric delay are shown in Figure 5-12: “Differences between backward and forward zenith tropospheric delay” , where the standard deviation of the differences is 0.004 m and the RMS of the difference is 0.007 m, the maximum difference is 0.015 m. In the figure the top panel is the magnitudes of the zenith tropospheric delays in backward and forward processing. The bottom panel is showing the differences of the zenith tropospheric delays between the backward and forward processing. The standard deviation and RMS of the differences are displayed in the middle of the plot.

The magnitude of the absolute zenith tropospheric delay is usually in the range of 1.5 ~ 2.5 m. Under no circumstances should this magnitude exceed 3.0 m.

Figure 5-12: Differences between backward and forward zenith tropospheric delay

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4. Check the DOP Values and Number of Satellites

Under normal conditions, the PDOP, HDOP and VDOP values should not exceed 5.0, 3.0, and 4.0, respectively. If significantly large DOP values are found in the plot, it might indicate that the PPP solution potentially have a problem at those epochs where large DOP values occur.

Normally, IPAS PPP should have at least 6 useable satellites for each epoch's data processing. If the number of satellites is less than 6, it might indicate that the PPP solution potentially have a problem at those epochs with less satellites.

Shown in Figure 5-13: “The DOP values and number of satellites” are the DOP values and the number of satellites for the example data set of this manual.

Figure 5-13: The DOP values and number of satellites

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5. Overall Quality Evaluation

If the conditions in Steps 1., 2. and 3. are all satisfied, the PPP solutions are usually considered to have achieved the expected accuracies for which the IPAS PPP software is designed. The conditions in Step 4. can usually be met when the conditions in Steps 1., 2. and 3. are satisfied.

Under exceptional circumstances, the DOP values might be larger than the above specified values (5.0, 3.0 and 4.0 for PDOP, HDOP and VDOP, respectively), but the quality of the IPAS PPP solutions is still considered acceptable given the conditions in Steps 1., 2. and 3. are all satisfied.

6. Re-Process the Data Using Different Precise Orbit and Precise Clock Files

Under normal conditions, the above conditions in Steps 1., 2. and 3. should be met after the IPAS PPP processing. If any one condition is not met after the processing, it is suggested to re-process the GPS data using precise orbit and precise clock files that are provided by a different agency. In very exceptional circumstances, precise clock corrections from a particular agency for one or more satellites might contain significantly larger errors.

If the satellites for which the clock corrections containing large errors are used in the IPAS PPP data processing, the PPP processing might produce unacceptable solutions with large errors. In this case, an alternative approach is to use precise orbit and precise clock from another agency and re-process the data.

The users should start from Step One: Data Preparation and download a different set of precise orbit and precise clock files.

In the above example, the "igs13984.sp3.Z" and "igs13984.clk.Z" that are generated by IGS are used for the data processing. Users may also use precise orbit and clock files generated by other agencies, such as JPL, CODE, etc. In the above example, if precise data from JPL are to be used in IPAS PPP, then "jpl13984.sp3.Z" and "jpl13984.clk.Z" should be downloaded.

7. Plot the trajectory of the GPS receiver

Clicking the IPAS GPS File button as shown in Figure 5-14: “Select the GPS receiver trajectory” , the users can select a GPS solution file and plot the trajectory of the GPS receiver.

This GPS solution file is generated by IPAS PPP and automatically stored under the “PPP” directory. This file has the same file name as the raw GPS data file except the solution file's extension is ".bin". In this example, the GPS solution file is "20061026_010813_rover_raw.bin" and it is stored under "D:/My_Project/PPP" directory.

Once the GPS solution file is selected and loaded into memory, the users can plot different trajectory profiles such as "latitude-longitude", "latitude-altitude", "longitude-altitude", "altitude-time", "X velocity-Time", "Y velocity-Time", "Z velocity-Time", etc.

Shown in Fig. 3.15 is the trajectory profile of the GPS receiver at the latitude-longitude domain. The standard deviation information for both latitude and longitude is shown in the bottom panel of the figure.

To show other profiles of the trajectory, just click on the corresponding title.

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Figure 5-14: Select the GPS receiver trajectory

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Figure 5-15: GPS receiver trajectory

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Step Four: Export ASCII solution file

IPAS PPP provides a feature to allow users to output GPS solutions in ASCII format based on the binary solution file.

After clicking on the Export tab in IPAS PPP user interface, shown in Figure 5-16: “Export ASCII solution file” , the first step is to select the IPAS PPP result file.

Figure 5-16: Export ASCII solution file

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As shown in Figure 5-17: “Select ASCII solution file” , after selecting the GPS binary result file, the users may enter the output file name of the ASCII format GPS solution.

After that, selecting the format "IPAS GPS (ASCII)" and clicking the Export button, the ASCII format IPAS PPP solution file is generated.

In this example, the ASCII format GPS solution file name is "20061026_010813_rover_raw.txt" and it is again stored to the "D:/My_Project/PPP" directory.

Figure 5-17: Select ASCII solution file

Both, the binary format GPS solution file (.bin file) and ASCII format GPS solution file (.txt file) are obtained. Either of them can be used to integrate with IMU data and to be processed by the IPAS Pro software to produce an integrated position and attitude solution.

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Chapter 6

IPAS CO+IPAS CO+ (Inertial Position and Attitude System Camera Orientation) is a software package for the automated computation of misalignment angles between IPAS reference frame to camera frame and for the transformation of IPAS Pro GNSS/IMU integrated solution to x, y, z, omega, phi and kappa as required by photogrammetric software.

Installation To install IPAS CO+ software, double-click the setup.exe file on the IPAS Pro /IPAS CO+ CD. Follow the instruction provided by the installation program.

License Configuration Software license from Leica Geosystems is required to run IPAS CO+.

IPAS CO+ requires two licenses. One is called IPAS CO and the other, for APM and Aerial Triangulation functionality, is called IPAS ABS.

IPAS CO+ license is delivered with a Entitlement ID and is using LGS FlexNet. IPAS ABS license is delivered with a ErdasNet license file.

For details on the license setup, please refer to “License setup” in the Installation Chapter.

Introduction to IPAS CO+

IPAS CO+ is a Windows-based software. It has three tab-windows, namely:

Transform Solution - This window provides the main functionalities for IPAS CO+. It will perform an automated misalignment calculation, and transform the IPAS Pro solution to x, y, z and omega, phi and kappa as required by photogrammetric software based on the event ID and photo ID files;

Compute Camera Misalignment - This window will compute the camera misalignment angles with respect to IPAS reference frame using an exterior orientation file from a bundle adjustment solution;

Point File Transform - This window will transform a point file from one coordinate system to another coordinate system.

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Figure 6-1: IPAS CO+ windows

Misalignment Angle Calculation

In IPAS CO+, there are two ways to calculate the misalignment angles: one is using the automated boresight functionality, while another one is based on an external supplied AT file (exterior orientation file) computed from another bundle adjustment software package such as ORIMA or LPS.

Automated Misalignment Calculation

IPAS CO+ provides an automated misalignment calculation functionality including automatic point matching (APM) and aerotriangulation (AT). It automatically generates the match points from the overlapped imageries and send those match point files to an ORIMA-based aerotriangulation engine.

The following files are required to perform the automated misalignment calculation:

• IPAS Pro Solution file generated from IPAS Pro, as described in the IPAS Pro user manual;

• Camera event file generated from IPAS Pro, as described in Appendix B;

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• Photo ID file generated from camera logging software, as described in Appendix B;

• Camera file in Australis format supplied by the camera vendor. For a detailed description of the Australis camera file, please refer to: http://www.photometrix.com.au/downloads/australis/AustralisGuide.pdf .

To start the automated misalignment calculation process:

• Click button to browse to the location of IPAS Pro solution file,

• Click button to browse to the location of event file as generated during IPAS Pro extraction process. If there is a timing offset between the actual timing of the shutter opening and the event time as saved in the event file, this value (in seconds) should be entered in the Event Offset box. The final calculated shutter open time is computed as

GPS Time (computed) = GPS Time (event) + event offset

• Click button to browse to the location of the photo ID file as generated by the camera logging software.

• Click button to start the window as described in Figure 6-2.

Figure 6-2: Select Camera File Window

Click on the Browse button to select the camera file as illustrated in Figure 6-3.

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Figure 6-3: Select Camera File Window

Please note the camera file used here is defined in Australis format. For a detailed description of the Australis camera file, please refer to: http://www.photometrix.com.au/downloads/australis/AustralisGuide.pdf .

After the camera file is select, the camera ID, focal length and principal point offset, radial distortion etc. are displayed in the camera file dialog window as shown in Figure 6-4.

Figure 6-4: Camera File Selected

Click on the Ok button to accept the camera file, a graphics window will display the trajectory of the flight based on IPAS Pro solution file.

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Figure 6-5: New Project Window Without Any Image

Click the Add Images button to launch the dialog window to add the images to the project as shown in Figure 6-6.

Figure 6-6: Select Image Files

Select images by click on the image name, holding on CTRL-key for multiple selections, or hold on SHIFT key to select all the images between two selections. After images are added, the project window will look like Figure 6-7.

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Figure 6-7: Project Window With Images Added

This window is explained in detail below.

The Project Window is divided into two sections: The Image List Window on the left side and the Image Footprint Window and the right side.

Image List Window

When the images are loaded, they are automatically divided into lines according their associated GPS times. All lines are listed by sequential line numbers assigned by IPAS CO+. All images associated with each line are listed under the line number. There is a check box in front of each line and each image. To select a line, just click on the check box in front of the line number; To deselect the line, just uncheck the check box in front of the line. Similarly, to select a image, just click on the check box in front of the image; To deselect the image, just uncheck the check box in front of the image. When some of the images are selected while other are not selected under the same line number, the check box of in front of the line number will be either a square if your desktop theme is setup as Windows XP style or a grayed check mark if your desktop themes is setup as Windows Classic style as shown in Figure 6-8.

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Figure 6-8: Lines With Some Images Selected

NOTE: A total of maximum 80 images can be used for the bundle adjustment, and each line shall have a minimum of 5 images selected for bundle adjustment. If more than 80 images are selected, only first 80 images will be used in the bundle adjustment. These restrictions do not apply to APM.

When right mouse button is clicked within the Image List Window, a menu will popup to allow the user to Collapse Lines and Expand Lines, Select All and Unselect All the images.

Figure 6-9: Menu from Right Mouse Button in File List Window

When Collapse Lines are selected, only the line numbers will be displayed in the Image List Window, the individual images will not be listed. When Expand Lines is selected, then all individual images are listed in the Image List Window. When Select All is selected, then all images are selected. When Unselect All is selected, then all images are unselected.

Image Footprint Window

The Image Footprint Window displays the trajectory of the flight and the footprint of all the images listed under the Image List Window. The footprints are calculated according to the trajectory information provided by the trajectory file and the default digital terrain model (DTM) file provided by IPAS CO+.

By unchecking the Trajectory check box at the left bottom of the window, the trajectory of the flight will not be shown in the footprint window anymore. Also the trajectory of the flight can be displayed as a solid line by selecting the Line button or as a dotted line by selecting Dots button.

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Each image can be displayed as a footprint by selecting the Footprint button or by its perspective center (PC) by selecting the PC button. The image display can be disabled by unchecking the Frames button.

When some lines or images are selected, the selected footprints will be displayed in red square or the selected PC centers will be displayed in red dots as shown in the following two figures.

Figure 6-10: Footprint Window with Some Images Selected (Footprint)

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Figure 6-11: Footprint Window with Some Images Selected (PC)

While the images are displayed in PC mode in the footprint window, the user can select or deselect additional images by dragging the left mouse button over the perspective centers of the images. When the images are added to or removed from the selected list, whether they are selected or unselected will be reflected at the Image List Window synchronously by the check boxes in front of the lines and the images.

Total number of images added to the project and the number of images selected are also displayed at the bottom of the Footprint Window.

Use the mouse Scroll Wheel to zoom in and zoom out Image Footprint Window.

Right click the mouse within the Image Footprint Window will turn to PAN mode. The cursor will become a PAN cursor . Drag the mouse to PAN within the Image Footprint Window. Right click on the mouse again within the Image Frame Window exits the PAN mode.

Once the appropriate images are selected, click on the Action button will bring up an Action Manager window as illustrated in Figure 6-12.

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Figure 6-12: Action Manager Window

This window first displays the camera file and camera ID, then number of lines selected and total number of imageries (frames) selected. Two actions can be taken at one time or separately: Run APM (automatic point matching), or Run AT.

If Run APM is selected, A default APM setting file located in the IPAS CO+ setting directory is specified. The user can use the browse button to specify a different APM setting file. There are three APM setting files which are provided with IPAS CO+, the user shall use the default one to start a project. For a detailed description of the APM setting file, please refer to Appendix C. The user also has an option to re-use the existing APM points by selecting the Re-Use Existing APM Points check box in order to save the processing time. If the check box is not selected, new APM points will be generated. The default selection is not to re-use the existing APM points. When the user is not completely certain about how previous APM points were generated, new points shall be generated to make sure all points are generated using the same settings.

If Run AT is selected, then the directory where the TIFF images are located is specified. The user can use the browse button to point to a different directory.

APM and AT can be done in the same run, or APM can be done first and all the match points are stored, AT can be re-run multiple times, if desired, based on the same set of match points from the previous APM.

Click on the Process button to start the APM and AT. When APM starts, a dialog window displays the progress of the APM. The first step of APM is to generate new points for each frame. 16 points are generated for each frame. User can click on the message expand button to view the expanded message window.

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Figure 6-13: Generating New Points during APM

The second step of the APM is to transfer the generated points to all overlapped images. The progress of this step is shown in Figure 6-14. The progress information includes the frame number currently under processing, the total number of frames, which point of current frame is being processed, total elapsed time, the percentage processed for current frame and the percentage processed for the entire APM computation.

Figure 6-14: Transferring Points during APM

After the APM is completed, AT is started by calling ORIMA triangulation engine. There are progress messages displayed in the message window.

Figure 6-15: AT Computation

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NOTE: IPAS ABS Licensing module is required to run AT.

Once the AT is completed, a window will display the computed omega, phi and kappa (x, y, z) misalignment angles and their corresponding RMS values. In addition, line by line residual values from the computed omega, phi and kappa (x, y, z) misalignment angles will be displayed in a table as illustrated in Figure 6-16 in unit of arcminutes. The Sigma0 value for match points is also displayed in this window in unit of microns.

Figure 6-16: Misalignment Angles calculated from AT

Press the Accept button to accept the AT computed misalignment angles. These angles will be brought back to the main IPAS CO+ window as shown in Figure 6-17. Click on Reject button to reject the calculated misalignment angles and adjust the input to perform the calculation again.

The lever arm values of the camera in the reference frame are required to be entered here as well. If there is any datum shift, it should be entered here as well.

Save these parameters to the project file by selecting menu File->Save.

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Figure 6-17: Computed Misalignment Angles

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Misalignment Calculation with External AT Solution

Manual misalignment calculation using external AT solution is managed in the Compute Camera Misalignment window.

Figure 6-18: Compute Camera Misalignment window

Use the following steps to perform the misalignment angle calculation:

• Click on the IPAS Solution File, Event File and Photo ID File buttons to select the corresponding files. Click on AT Solution File button to select AT file and select the AT file format.

• Input the camera event offset time if there is any.

• Select the camera mounting angle.

• Select the Coordinate System in which the AT file was resolved. If a Projection System was selected, then a popup window will appear to ask the user to select the projection and zone information. If a LSR system is selected, a popup window will appear to ask the user for the anchor point coordinates.

NOTE: Note: If a LSR system is used to compute the AT file, then the same anchor point used during the AT shall be used here to perform the misalignment angle calculation.

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• Select the datum used for the AT file.

• Select the vertical reference used for the AT file.

• Select the horizontal and vertical units used for the AT file.

• Click on Go button and calculation will start. Once the calculation is done, a Camera Misalignment Results window will appear to display the misalignment angles calculated for each individual photo. User can select/deselect whether to use individual photo for the calculation of the misalignment angles by checking and unchecking the corresponding the check box under the Use column.

Figure 6-19: Camera Misalignment Results window

In order for the misalignment angles to be valid, the computed omega, phi and kappa residuals (d-omega, d-phi, d-kappa) would have to be consistent among all the photos. The standard deviations of the computed d-omega, d-phi and d-kappa shall represent the accuracy of roll, pitch and heading from the *.sol file as well as the accuracy of the omega, phi and kappa values supplied from the AT file. If the residuals from one or more photos are significant different from the other photos, then those photos should be de-selected from the list using Check Boxes under the Use column.

Click on Apply button will bring the calculated misalignment angles to the Transform Solution window.

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NOTE: Note: In order to achieve best results, the misalignment angle should be calculated in the LSR frame, which means the AT file shall be provided in the LSR frame as well.

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Transform Solution

The Transform Solution window will perform the transformation from IPAS Pro solution to x, y, z, omega, phi and kappa as required by photogrammetric software.

The following information is required for the transform:

• IPAS Solution file, as described in the IPAS Pro manual;

• Camera event file, as described on Appendix B;

• Photo ID file, as described in Appendix B;

• Verify the misalignment angles calculated either automatically from IPAS CO+ APM and AT or from an calculated manually from an external supplied AT solution;

• Camera lever arms; and

• Datum shift.

Figure 6-20: Transform Solution window

Use the following steps to perform the transform:

IPAS CO+

IPAS Pro90

• Click on the IPAS Solution File, Event File and Point ID File buttons to select the corresponding files.

• Input camera event time offset if there is any, otherwise set the value to 0.0.

• Select camera mounting angle,

• Confirm the misalignment angles' values and units are right,

• Set the lever arm values

• Set Datum shift if there is any, otherwise set to 0.0 for all x, y, z datum shifts,

• Set output directory and file name,

• Set camera orientation convention. The following convention can be selected from the drop down list:

- ASCII output- default format

- PATB format

- LPS format

- TerraPhoto

Please refer to Appendix B for detail description of the formats.

• Select reference frame information for the output file including:

- Coordinate system - if a projection system is selected, then a popup window will appear to ask for projection and zone information. If a LSR system is selected, a popup window will appear to ask the user for the anchor point coordinates,

- Select Datum for the output file,

- Select vertical reference, either ellipsoidal or MSL. Currently Australian 1998 Geoid model, Canada CGVD28, EGM96 geoid model, Japanese Geoid Model 2000, Latvia LV98 and NAVD88 are supported.

- Select horizontal and vertical coordinate units required for the output file

• Click on Go button will start the calculation.

• The output file is described in Appendix B.

Point File Transform

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Point File Transform

The Point File Transform window will transform a point file from one coordinate system to another.

Click on Compute Center of Gravity button will compute the anchor point based on the points included the point file.

Figure 6-21: Point Transform window

IPAS CO+

IPAS Pro92

Open and Save Camera parameters and file paths can be saved into a IPAS CO project file. The project file can be opened for reuse.

To save a project, select File menu, then Save, select the file name used to save the camera parameters. The camera file is written with the extension .ptu. The following parameters are saved:

• File paths for IPAS solution file, event file, photo ID file and AT solution file

• Camera mounting direction

• Event time offset

• Misalignment angles

• Lever arms

• Datum shift

• Image names used in APM and AT

To open the IPAS CO project file, click on File, then select Open and browse to the .ptu file. The saved file paths and camera parameters will be brought into the corresponding fields of the Transform Solution window.

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Appendix A

GNSS Input FormatIPAS Pro requires an ASCII post-processed GPS solution file. The file format is defined as following:

• GPSTime - GPS Time (Seconds of the week)

• Latitude - Latitude (Decimal Degrees)

• Longitude - Longitude (Decimal Degrees)

• H-Ell - Ellipsoidal Height (meters)

• Q - Quality Number, an integer number

• SDNorth - Latitude Standard Deviation (meters)

• SDEast - Longitude Standard Deviation (meters)

• SDHeight - Height Standard Deviation (meters)

• VNorth - North Velocity (meters/second)

• VEast - East Velocity (meters/second)

• VUp - Up Velocity (meters/second)

• SD-VN - North Velocity Standard Deviation (meters/second)

• SD-VE - East Velocity Standard Deviation (meters/second)

• SD-VH - Height Velocity Standard Deviation (meters/second)

• NS - Number of Satellites

• PDOP - PDOP

Any header or comments can exist in the file, but first character of that line must be a semicolon (;).

The following is an example of a section of an acceptable GPS solution file:

IPAS Pro94

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Appendix B

IPAS CO+ File Format DescriptionsCamera Event File Camera event file is an ASCII file. Each line contains the following information:

• Event GPS Time (week seconds)

• Event number

If a row is only for comment purpose, a ’;’ shall be the first character of the row.

Photo ID File Photo ID file is an ASCII file. Each record contains the following information:

• Event GPS Time (week seconds)

• Photo ID

If a row is only for comment purpose, a ’;’ shall be the first character of the row.

Photo ID file in *.csv format can be read directly by IPAS CO now. Each record for this file has a structure of:

GPSTime (week secconds), ImageName

Only first two fields are used by IPAS CO. Therefore if the record has additional fields, they do not affect IPAS CO.

AT Files Two type of AT files are supported, one is called IXYZOPK and the other one is called ORMA PATB format.

IXYZOPK Format AT File

The IXYZOPK format file is a ASCII file. Each record (line) consists of:

• Photo ID

• X

• Y

• Z

• Omega

• Phi

IPAS Pro96

• Kappa

Again if a row is only for comment purpose, a ’;’ shall be the first character of the row.

ORIMA PATB AT File ORIMA PATB AT file consists of exterior orientation parameters for each image. Each parameter has a block of 4 lines. The structure of the block is:

• Image ID Camera ID

• Flags: Disregard [0,1] Rotation sequence [0,1,2]

• Coordinates of projection center X Y Z

• Orientation angles Omega Phi Kappa [gon]

Interpretation of flags:

• Disregard = 0 => Image is used

• Disregard = 1 => Image is disregarded

Rotation from object to image system:

• Rotation sequence = 0 => X-axis, Y-axis, Z-axis

• Rotation sequence = 1 => Y-axis, X-axis, Z-axis

• Rotation sequence = 2 => X-axis 100[gon] fixed, Y-axis, X-axis, Z-axis

The file is free formatted. Each parameter must be separated by at least one space character. Below is an example of the file.

**** Start of Data ****

1_1012 dss_hkk

0 0 1 0 0.00000

1378.33746158 224.767091959 975.481531886

-1.16284250374 -0.461422760170 75.8838647773

1_1011 dss_hkk

0 0 1 0 0.00000

1154.91811588 282.323029356 970.386572587

0.489754072088 -0.776188263824 76.4722729664

Output Files There are four types of output formats supported in the IPAS CO when transforming an IPAS Pro solution file to an output file. And they are Standard ASCII, PATB, LPS and TerraPhoto. These formats are described in the following section in detail.

Standard ASCII

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This format will output all of the transformed values for each event into columns on a single row. The output file is pre-pended with a header line which reflects the units chosen in the transformation. The Easting and Northing are in the user selected projection system. The Height is in the user selected vertical reference.

ID Event# GPS Time(s) Easting(metres) Northing(metres) Ell Ht(metres) Omega(deg) Phi(deg) Kap(deg) Lat(deg) Lon(deg)

174230360 11 451419.683656 549050.336 4321967.926 514.179 -0.28624 0.78102 -16.58954 39.04540362 117.56681555174230390 12 451422.612737 548879.648 4322031.276 516.141 1.39473 0.54696 -16.67999 39.04598402 117.56484775174230410 13 451425.551820 548708.738 4322092.943 517.672 1.06902 0.46450 -15.63299 39.04654925 117.56287723174230440 14 451428.496101 548537.467 4322152.554 517.863 1.60459 -0.29796 -14.92201 39.04709593 117.56090237174230470 15 451431.377483 548368.899 4322208.980 516.794 1.22220 -0.45445 -15.35683 39.04761372 117.55895848

PATB

This is the PATB format as supported in the program ORIMA. Each event is printed out over 4 rows in the output file. The structure of the file is:

Row 1:Image ID Camera IDRow 2:Flags: Disregard [0] Rotation sequence [0] Unused [0] Unused [0] GPS Time [s]Row 3:Coordinates of projection center X Y Z (in user selected projection)Row 4:Orientation angles Omega Phi Kappa [deg]

174230360 CAMERA_ID 0 0 0 0 451419.68366 549050.33593057 4321967.92587762 514.17897075 -0.28624186211 0.78101538229 -16.58953533066 174230390 CAMERA_ID 0 0 0 0 451422.61274 548879.64756693 4322031.27574019 516.14121403 1.39472630373 0.54696225104 -16.67999209078 174230410 CAMERA_ID 0 0 0 0 451425.55182 548708.73772100 4322092.94329618 517.67153322 1.06901786731 0.46450072602 -15.63298505995

LPS

This option creates 3 files which help to facilitate data entry into Leica LPS and ORIMA. The user will specify the name of the first file, and two other files will be created with a (.gps) and a (.imu) extension. The units and projection of the output data will be user-specified.

The record content for the first file is:

IPAS Pro98

PhotoID EventID X Y Z Omega Phi Kappa

Note: To use this file as exterior orientation input in LPS, the user must manually edit the second column (EventID), and replace the values with the full image names (without file path) associated with the PhotoIDs.

File 1:174230360 11 549050.336 4321967.926 514.179 -0.28624 0.78102 -16.58954174230390 12 548879.648 4322031.276 516.141 1.39473 0.54696 -16.67999174230410 13 548708.738 4322092.943 517.672 1.06902 0.46450 -15.63299174230440 14 548537.467 4322152.554 517.863 1.60459 -0.29796 -14.92201174230470 15 548368.899 4322208.980 516.794 1.22220 -0.45445 -15.35683174230500 16 548192.656 4322265.429 515.585 -2.29184 0.62298 -15.57313

The (.gps) file is used as GPS antenna entry in ORIMA. The structure of this file is:

PhotoIDX Y ZtimeSig-XSig-YSig-ZOff-XOff-YOff-ZProfileID

Note: In IPAS CO output, the values for Sig-X, Sig-Y, Sig-Z, Off-X, Off-Y and Off-Z will always be 0. The ProfileID will always be 1.

File 2: (.gps)174230360 549050.336 4321967.926 514.179 451419.683656 0.000 0.000 0.000 0.0 0.0 0.0 1174230390 548879.648 4322031.276 516.141 451422.612737 0.000 0.000 0.000 0.0 0.0 0.0 1174230410 548708.738 4322092.943 517.672 451425.551820 0.000 0.000 0.000 0.0 0.0 0.0 1174230440 548537.467 4322152.554 517.863 451428.496101 0.000 0.000 0.000 0.0 0.0 0.0 1174230470 548368.899 4322208.980 516.794 451431.377483 0.000 0.000 0.000 0.0 0.0 0.0 1174230500 548192.656 4322265.429 515.585 451434.366047 0.000 0.000 0.000 0.0 0.0 0.0 1

The (.imu) file is used as IMU angle entry in ORIMA. The structure of this file is:

PhotoIDOmega Phi Kappa SigmaOmega SigmaPhi SigmaKappa

Note: In IPAS CO, the values for SimgaOmega, SimgaPhi and SigmaKappa will always be 0.

File 3: (.imu)174230360 -0.28624 0.78102 -16.58954 0.00000 0.00000 0.00000174230390 1.39473 0.54696 -16.67999 0.00000 0.00000 0.00000174230410 1.06902 0.46450 -15.63299 0.00000 0.00000 0.00000174230440 1.60459 -0.29796 -14.92201 0.00000 0.00000 0.00000174230470 1.22220 -0.45445 -15.35683 0.00000 0.00000 0.00000174230500 -2.29184 0.62298 -15.57313 0.00000 0.00000 0.00000

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TerraPhoto

When this option is selected, IPAS CO will create a exterior orientation file inTerraPhoto format. The file format is:

[TerraPhoto image list v2]

GPSTime (week seconds) East (m) North (m) Height (m) Heading (degrees) Roll (degrees) Pitch (degrees) HistogramInformation CameraIndex ImageName

A example of the file is shown in the following:[TerraPhoto image list v2]328756.563910 270470.685 4716243.056 2442.205 -9.95328 -5.61941 2.87508 N 0 17150110100088G3.tif328763.834040 270470.028 4716774.495 2440.281 -8.72901 2.17106 3.04531 N 0 17150110100089G3.tif328771.060280 270484.358 4717304.788 2442.555 -8.05026 -0.67541 4.20221 N 0 17150110100090G3.tif328778.359350 270496.282 4717834.399 2449.091 -9.36022 -2.06351 3.79396 N 0 17150110100091G3.tif328785.749270 270501.756 4718367.581 2448.515 -8.73227 -0.11616 2.81796 N 0 17150110100092G3.tif

IPAS Pro100

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Appendix C

APM setting file DescriptionThis Section contains a description of the setting file that is used during Automated Point Matching (APM). At times, it may be necessary for you to edit the Tie Point Pattern file to achieve the best ties between your images.

Please note changes to the file are made by hand editing the contents to suit the needs of the project. Care must be taken not to introduce errors into the file that might cause problems in reading the file.

Table 6-1: APM Settings File

Keyword Value Type Unit Ran

ge Default Description

PATTERN_SAMP_START Double Percent 0-100 15 Across line start position of the first point to find.

PATTERN_SAMP_REPEAT Double Percent 0-100 35 Across line repeat positions for each row of lines to find.

PATTERN_SAMP_USER Multi-Double

Percent 0-100 Across line positions for each row of lines to find, specified by the user (in percent), e.g. PATTERN_SAMP_USER 10.0 35.0 55.0 90.0When this field is present, the PATTERN_SAMP_START and PATTERN_SAMP_REPEAT will be ignored.

PATTERN_LINE_START Integer Pixels >0 500 Along line start position of the first pixel to find.

PATTERN_LINE_REPEAT Integer Pixels >0 1500 Along line repeat distance to search for points until the end of the line. APM will automatically adjust this value internally if the value given is too large and thus not provide the required amount of points to form a strong photogrammetric solution. The strongest geometry for points is to have three columns of points between projection centers, if the value given here does not meet this criteria, the software will adjust this automatically.

IPAS Pro102

PATTERN_LINE_USER Multi-double

Percent 0 - 100 Along line positions for each set of sample patterns to find, specified by the user (in per-cent of total line length), e.g. PATTERN_LINE_USER 10.0 35.0 55.0 90.0

When this field is present, the PATTERN_LINE_START and PATTERN_LINE_REPEAT will be ignored.

INLINE_INIT_MASTER_SEARCH_SIZE

Integer Pixels >0 100 This is the width and height of the initial search area around the seed point on the master image to locate an interest point.

INLINE_TARG_TEMPLATE_SIZE

Integer Pixels >0 15 This is the size of the image template given in pixels.

INLINE_L1_ELEV Double Proj Dist Unit

1000 If the ELEV_MODE from above is set to MANUAL then this is the L1 rectification elevation used within the ADS APM to rectify the master and target patches.

INLINE_MIN_ELEV Double Proj Dist Unit

900 If the ELEV_MODE from above is set to MANUAL then this is minimum elevation used for the epipolar search.

INLINE_MAX_ELEV Double Proj Dist Unit

1100 If the ELEV_MODE from above is set to MANUAL then this is maximum elevation used for the epipolar search.

INLINE_RMS_CUTOFF_PER_PIXEL

Double Unitless >0 1.5 Represents gray value differences between the master and target templates.

INLINE_CORRELATION_CUTOFF

Double Unitless 0-1.0 0.7 Cross-correlation threshold for inline matches.

INLINE_PARALLAX_CUTOFF

Double Pixels 0 4.0 Parallax threshold used for discarding points while finding points in the same strip.

INLINE_EXPECTED_PARALLAX

Integer Pixels >0 6 The a priori parallax error. This affects the search width and minification logic for the target area. Increasing this value will increase the number of pixels searched (at the price of speed). Increase this value (and the cutoff value) when large initial parallaxes are observed.

TRANSFER_TEMPLATE_SIZE

Integer Pixels >0 15 Size of the image template used for transfer operation.

TRANSFER_CORRELATION_CUTOFF

Double Unitless 0-1.0 0.7 Threshold correlation value to accept points during transfer.

Table 6-1: APM Settings File

Keyword Value Type Unit Ran

ge Default Description

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TRANSFER_PARALLAX_CUTOFF

Double Pixels >0 9.0 Parallax threshold used for discarding points during a transfer operation.

TRANSFER_INLINE Integer Boolean 0 or 1 0 This option is used when adding bands to a strip and transferring points to these new bands without having to re-run the point finding operation on the entire strip. Setting value to 1 will allow the existing points to be transferred to newly added band in the same strip.

SUBPIXEL_SEARCH Integer Boolean 0 or 1 1 Sets whether subpixel matching estimation will be used. Subpixel matching should improve the matching accuracy. This should be reflected in a smaller a-posteriori sigma0 in the AT. This function will increase matching time.

RECTIFY_SUBBLOCK_SIZE Integer Pixels >0 4 The L1 subpatch to be rectified. A larger value will increase speed but possible decrease rectification accuracy (depending on flight dynamics). A smaller value will decrease speed but increase rectification accuracy.

ALLOC_MAXSIZE Integer Bytes >0 4000000 The largest allowable buffer memory allocation size to be created for reading image buffers.

INTEREST_WINDOW_SIZE Integer Pixels >0 11 Interest operator window size (value should be an odd number).

INTEREST_CIRCLE_CUTOFF

Double Unitless 0-1.0 0.75 Interest operator "roundness" cutoff for determine best interest point.

APM_MODE String FULL, INLINE_ONLY, TRANSFER_ONLY

FULL This tells the APM operation to find and transfer points. Allows for transfer of points only, find new points within ADS Lines only, or perform both operations.

Table 6-1: APM Settings File

Keyword Value Type Unit Ran

ge Default Description

IPAS Pro104

ELEV_MODE String DEM, MANUAL

DEM This elevation mode is used to select the method which APM will use to set the terrain height seed point for finding points. Valid entries are DEM or MANUAL. The DEM setting will force APM to use the DEM specified by the user in the XPro initialization file or alternatively with the DEM_NAME. IPAS CO+ installation supplies a global JPTF DEM with grid spacing of 30 arc seconds (derived from USGS GTOPO30 dems). Accuracy varies by location but is typically better than 100m.( MANUAL will force the APM to use elevations defined within this settings file.

DEM_NAME String When the elevation mode is set to DEM, this value can identify the full path of the JPTF dem file. APM will use the default DEM specified in the XPro initialization file.

DEM_ACCURACY Double Proj Dist Unit

>0 50 This is a scalable value that allows you to set the perceived accuracy of the DEM. Since the JPTF DEM is roughly 1 km spacing, not all regions on the surface of the earth can be represented very well. For instance, mountainous regions with many valleys and fast changing terrain will not be described very well with a coarse JPTF DEM. This value allows the APM to expand the search along the epi-polar line for points. A larger DEM_ACCURACY value will open a longer search space along the epi-polar line to search for points. A larger value will also generate more samples for the APM to test, thus slowing down the overall APM process. For flat terrain this value can be set lower, but for mountainous regions, this might be set higher to aid in finding more points.

INLINE_MATCHMODE Integer Integer 1,4 1 This is the algorithm used to match points. 1 = Conventional epi-polar constrained cross-correlation; 4 = Hierarchical search cross-correlation

TRANSFER_MATCHMODE Integer 1,4 1 This is the algorithm used to match points. 1 = Conventional epi-polar constrained cross-correlation; 4 = Hierarchical search cross-correlation

USE_MULTITHREADING Integer Boolean 0 or 1 0 Whether to use multi-threaded approach

Table 6-1: APM Settings File

Keyword Value Type Unit Ran

ge Default Description

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APM_MODE FULL

This is will always be set to FULL for running APM from within XPro. This tells the APM operation to find and transfer points.

ELEV_MODE DEM

This elevation mode is used to select the method which APM will use to set the terrain height seed point for finding points. Valid entries are DEM, or MANUAL.

The DEM setting will force APM to use a USGS GTOPO30 DEM. The USGS GTOPO30 DEM is coarse, 30 arc second, grid of points with global coverage. These are freely downloadable and usable from: http://edc.usgs.gov/products/elevation/gtopo30/gtopo30.html

MANUAL will force the APM to use elevations defined within this settings file.

NUM_THREADS Integer >=1 By default, the number of threads created will be equal to the number of processors de-fined in the environment variable (NUMBER_OF_PROCESSORS). The user can set this to any value they choose.

TP_FILE_FORMAT String IPT, IPF, BOTH

IPT IPF is the old SOCET SET image point format (which can be imported directly into Orima). IPT is the new format in XPro.

PRESMOOTH_IMAGES Integer Boolean 0 or 1 1 Smooth the imagery before matching. This is useful with SH40 data where there is a mix of PAN and GRN lines. The GRN lines tend to be noisier than the pan, so smoothing improves matching performance. Not needed for normal SH52 data.

POINT_CLUSTER Integer Boolean 0 or 1 0 Option to try to match a single point at the pre-calculated line/sample position, or a clus-ter of 5 points at the line/sample position. The cluster will have 5 points equally distrib-uted with an area with the width of INLINE_INIT_MASTER_SEARCH_SIZE. Final matched points will likely move from their pre-calculated positions in order to find an appropriate interest point - or no match may result due to poor imagery.

Table 6-1: APM Settings File

Keyword Value Type Unit Ran

ge Default Description

IPAS Pro106

DEM_NAME

Leica XPro intallation supplies a global JPTF DEM. gtopoDem_ell.jptf unifies all GTOPO30 dems into 1 file giving the global coverage. APM will use the default DEM specified in the XPro initialization file. Still, this value can be used to override and identify the full path of the JPTF dem file.

DEM_ACCURACY 100

This is a scalable value that allows you to set the perceived accuracy of the DEM. Since the GTOPO30 DEM is roughly 1 km spacing, not all regions on the surface of the earth can be represented very well. For instance, mountainous regions with many valleys and fast changing terrain will not be described very well with a coarse GTOPO30 DEM. This value allows the APM to expand the search along the epi-polar line for points. A larger DEM_ACCURACY value will open a longer search space along the epi-polar line to search for points. A larger value will also generate more samples for the APM to test, thus slowing down the overall APM process. For flat terrain this value can be set lower, but for mountainous regions, this might be set higher to aid in finding more points.

PATTERN_SAMP_START 5

Across line start position of the first point to find, this value is given in percentage.

PATTERN_SAMP_REPEAT 20

Across line repeat positions for each row of lines to find, this value is given in percentage.

PATTERN_LINE_START 500

Along line start position of the first pixel to find, this value is given in pixels.

PATTERN_LINE_REPEAT 500

Along line repeat distance to search for points until the end of the line. APM will automatically adjust this value internally if the value given is too large and thus not provide the required amount of points to form a strong photogrammetric solution. The strongest geometry for points is to have three columns of points between projection centers, if the value given here does not meet this criteria, the software will adjust this automatically.

INLINE_INIT_MASTER_SEARCH_SIZE 100

This is the size of search area at the seed point around the epi-polar line, given in pixels.

INLINE_TARG_TEMPLATE_SIZE 15

This is the seed size of the target template given in pixels.

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INLINE_L1_ELEV 1000

If the ELEV_MODE from above is set to MANUAL then this is the L1 rectification elevation used within the ADS APM to rectify the master and target patches. This value is given in meters.

INLINE_MIN_ELEV 300

If the ELEV_MODE from above is set to MANUAL then this is minimum elevation used for the epi-polar search. This value is given in meters.

INLINE_MAX_ELEV 1200

If the ELEV_MODE from above is set to MANUAL then this is maximum elevation used for the epi-polar search. This value is given in meters.

INLINE_RMS_CUTOFF_PER_PIXEL 1.5

Represents gray value differences between template and slave on a pixel ratio. This value is unitless.

INLINE_CORRELATION_CUTOFF 0.7

Cross-correlation threshold for inline matches. Values are unitless (0-1).

INLINE_EXPECTED_PARALLAX 3

The a priori parallax error. This affects the search width and minification logic for the target area. Values are given in pixels.

INLINE_PARALLAX_CUTOFF 5

Parallax threshold used for discarding points while finding points in the same strip. Values are in pixels.

TRANSFER_CORRELATION_CUTOFF 0.7

Threshold correlation value to accept points during transfer. Values are unitless (0-1).

TRANSFER_PARALLAX_CUTOFF 5

Parallax threshold used for discarding points during a transfer operation. Values are given in pixels.

TRANSFER_TEMPLATE_SIZE 15

Size of the template used for transfer operation. Values are given in pixels.

IPAS Pro108

TRANSFER_INLINE 0

This option is used when adding bands to a strip and transferring points to these new bands without having to re-run the point finding operation on the entire strip. Setting value to 1 will allow the existing points to be transferred to newly added band in the same strip. Value of 0 is default and for the normal workflow.

RECTIFY_SUBBLOCK_SIZE 8

The L1 subpatch to be rectified, unit is pixels.

ALLOC_MAXSIZE 4000000

The largest allowable buffer memory allocation size to be created for reading image buffers, values is in bytes.

INTEREST_WINDOW_SIZE 7

Interest operator window size, the value is in pixels.

INTEREST_CIRCLE_CUTOFF 0.75

Interest operator "roundness" cutoff

APM Settings File Example

APM Setting file example:

APM_SETTINGS

;; apm settings file April 2007

APM_MODE FULL

ELEV_MODE DEM

DEM_ACCURACY 50

PATTERN_SAMP_START 15

PATTERN_SAMP_REPEAT 35

;; PATTERN_SAMP_USER will override PATTERN_SAMP_START and PATTERN_SAMP_REPEAT

PATTERN_SAMP_USER 10.0 35.0 55.0 90.0

PATTERN_LINE_START 500

PATTERN_LINE_REPEAT 1500

;; PATTERN_LINE_USER will override PATTER_LINE_START and PATTERN_LINE_REPEAT

PATTERN_LINE_USER 10.0 35.0 55.0 90.0

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INLINE_INIT_MASTER_SEARCH_SIZE 100

INLINE_TARG_TEMPLATE_SIZE 15

INLINE_L1_ELEV 1000

INLINE_MIN_ELEV 900

INLINE_MAX_ELEV 1100

INLINE_RMS_CUTOFF_PER_PIXEL 1.5

INLINE_CORRELATION_CUTOFF 0.7

INLINE_EXPECTED_PARALLAX 4

INLINE_PARALLAX_CUTOFF 6

TRANSFER_CORRELATION_CUTOFF 0.7

TRANSFER_PARALLAX_CUTOFF 7

TRANSFER_TEMPLATE_SIZE 15

TRANSFER_INLINE 0

SUBPIXEL_SEARCH 1

RECTIFY_SUBBLOCK_SIZE 4

ALLOC_MAXSIZE 4000000

INTEREST_WINDOW_SIZE 11

INTEREST_CIRCLE_CUTOFF 0.75

TP_FILE_FORMAT IPF

IPAS Pro110

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IndexSymbols*.GMB 22*.GPS 22*.IMU 22*.TM 22

AAnalyzing Data 35APM file descriptions 101

Bboresight angle 28

CCompare files 47configuration

processor 25Configuration Options 11Create A New Project 15

Ddifference file 47Differences 47

Eextract directory 19Extracted file types 21extracted files 19extraction log 21

FFile Converter 26

GGimbal data plots 41Gimbal Raw data 41GPS antenna 27GPS data plot 40GPS Input Format 93, 95GPS solution plot 42GrafNav 24

IImport button 24

IMU Data Extraction 18IMU extraction log window 18IMU File 22IMU lever arm 28IMU Raw data 38Installation 3, 73Introduction to IPAS CO 73IPAS 51IPAS CO camera file 92IPAS CO+ 73IPAS PPP Data Preparation 54IPAS PPP Export ASCII solution 70IPAS PPP Installation 53IPAS PPP Processing 54IPAS PPP Quality Check 63IPAS Pro 17IPAS10 1IPAS20 1

LLatitude 93Launching IPAS Pro 13lever arm 27License Configuration 73log window 21Longitude 93

MMake Differences 47Misalignment Angle Calculation 74

Nnew project 15

OOpen Project 13Output File 96

PPlots 35Point File Transform 91Processed Data Plots 35Processing

Main Page 17Processing Configuration 25Processing Options 17

112

Index

progress meter 20

RRaw Data 18, 37raw data

file location 19file types 20

Raw Data Plots 37Real-time Solution 42Real-time Solution Plots 42Result File button 36

Ssolution file

compare 47Start Processing 31Step 70System Requirements 3

Ttrajectory 36trajectory plot 40Transform Solution 89

UUser time file 20