GNSS Networks and Reference Stations...Innovative Solutions from Leica Geosystems VADASE - Real-time motion estimation on-board a stand-alone GNSS receiver GNSS Networks and Reference

Innovative Solutions from Leica Geosystems

VADASE - Real-time motion estimation on-board

a stand-alone GNSS receiver

GNSS Networks and Reference Stations

The best answers combine the smartest solutions

When you are interested in high rate and real time cm-level fast motion

detection of an autonomous station, or be independent of any external

reference, the VADASE provides the solution – when it has to be right.

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VADASE – Velocity & Displacement Engine

Outline

Motivation & Background

Application examples

University of Rome

Leica external pre-evaluation

Integrated Solution:

RefWorx

SpiderQC

Leica internal application testing

Use Cases

Conclusion

Innovative solution for real-time motion estimation

on-board a stand-alone GNSS receiver

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Using GPS for Seismology ...

Historically mainly to study long-term deformation, daily solutions

(plate tectonics, crustal deformation, post-glacial rebound, subsidence)

More recently research using kinematic post-processed using

Instantaneous differential positioning

Precise Point Positioning

Both methods not fully autonomous and not fully available in real time

Aim to determine seismic displacements in real-time ...

1 cm accuracy / Global reference frame / within minutes after Event

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University of Rome “Sapienza” - Geodesy and Geomatics division :

Realised growing importance of GNSS in seismic application

Goal:

Real-time site displacement from a single stand-alone GNSS receiver

Idea: VADASE

Variometric Approach for Displacements Analysis Stand-Alone Engine


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Technology applied:

Velocity Estimation

Epoch-by-Epoch LSQ estimation of site velocity using high-rate (i.e. 1 Hz or

more) carrier phases observations and broadcast orbits

Waveform or Displacement determination

Integration of estimated velocities lead to high-rate site motion waveform and

displacement information

No correction signal needed!

Patent applied by University of Rome


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Application Examples

University of Rome

Japan: Tohoku-oki earthquake (post processed)

Leica external pre-evaluation

Geospatial Information Authority of Japan (GSI)

UNAVCO testing facilites – Waveform simulation

Leica internal application testing

Kinematic „Train“ test

Motion Test Plaform (video)

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Studies performed by University of Rome - Earthquakes:

Comparison of VADASE approach performed by post-processed

data from various seismic events

Example from Tohoku-oki earthquake / Mw 9.0, 11.03.2011 / 1 Hz

data

Application Examples: Earthquake

NRS Webinar - VADASE with RefWorx V3.20 - June 2015

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Tohoku-oki earthquake / Mw 9.0, 11.03.2011

Estimated velocities

IGS Site “MIZU”

140 km from

epicenter


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Integrated velocities Displacement



2.4 m Total horiz.

displacement

2.2 m – DE

2.9 m – MAX DE

1.0 m – DN

1.8 m – MAX DN

0.1 m – DH

0.3 m – MAX DH

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Comparison with TRACK and APP



Correlation coeff. higher

than 0.90

RMSE within 5 cm (plane)

TRACK = Diff. Pos.

APP = PPP solution

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Geospatial Information Authority of Japan (GSI)

March 2014 GSI made evaluation using GR10 with prototype on-board

integration of original “Rome-VADASE” application

Tests under static & various dynamic conditions and obstructed area

Comparison made to RTK-Lib with double difference processing

Application Examples: GSI Evaluation

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Japan GSI – Test Results: Motion 4 cm/s


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Japan: GSI – Test Results: Static


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USA: UNAVCO Waveform Simulation (November 2014)

Preliminary testing on pneumatic controlled test stage.

Test stage still under development to obtain better

ground truth reference data about movement.

Reference data at up to 200 samples per sec. [sps]

Allows sinusodial movement in approx.

NW-direction no height shifts

Comparison done between:

RT-PPP (50Hz) vs. VADASE (5 Hz)

Application Examples: UNAVCO Evaluation

2020

-PPP

PPP



Overview

~ 4 min

„Stage“ = 200 Hz

Reference position

PPP @ 50Hz

VADASE @ 5 Hz


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Zoom –

Start of Experiment


PPP

-PPP

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Zoom –

End of Experiment


PPP

-PPP

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-PPP



Position difference

between

„Stage“ reference

and GPS based

results of

RT-PPP and

VADASE


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Leica Geosystems VADASE on-board GR-Series receiver:

Velocity And Displacement Autonomous Solution Engine

Purpose: Detection of fast relative displacement in real time

Sensitivity: ~ 1cm/sec. horizontal / ~ 2 cm/sec. vertical change

Method: Time-difference GNSS observations & broadcast orbits to

estimate velocity in E/N/U and integration to obtain relative

displacement at 1-20 Hz rate

Non-Purpose: Detection of absolute position or slow movement

Benefits: Fully autonomous & real time

No reference data / corrections required

Integrated Solution

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RefWorx 3.20 will enable users to explore the VADASE feature. With

this FW, users can:

Disable and enable the engine.

Stream and/or log the velocities and displacements.

Receive event log messages when displacement occur.

Configure the sensitivity of displacement detection.

Integrated Solution in RefWorx

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The Velocity & Displacement Engine:

Requires an accurate (≈ 50 cm) receiver reference position for

precise velocity and displacement calculations.

Supports all satellite systems used for position computation

onboard GR and GM receivers

Computes velocities and displacements with the following rates:

1, 2, 5 , 10 and 20 Hz

Integrated Solution in RefWorx 3.20

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Antenna velocities and displacements can be streamed and/or logged using

two Leica proprietary NMEA messages:

LVM – Leica Velocity Measurement. It contains:

East, North and Up velocities, velocities variances and covariances

Number of satellites used to compute the ENU velocities

LDM – Leica Displacement Measurement. It contains:

East, North and Up displacements, displacements variances and covariances

Number of satellites used to compute the ENU displacements

Time and date of the last event the displacement was reset to zero

Flag indicating the reason of the reset.

Epoch-to-epoch and overall data completeness ratio.

NMEA LVM and LDM messages

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Using SpiderQC to display the VADASE results


SpiderQC v5.3 allows:

decoding the LVM- and LDM-NMEA messages

logging the LVM- and LDM-NMEA messages into text files

displaying in real-time the velocities and displacements

displaying offline (or in „post-processing“) the velocities and displacements

report notifications / email sending in case velocities or displacements

thresholds are exceeded

Multiple concurrent connections

(e.g., different sensors, different NMEA streams) are supported

3535


Leica “Train”-Testrail: Dynamic performance – 20 Hz

Goal: Analyse dynamic behaviour

2 runs continuous (max) speed

3rd run varying speed

accellerate / decellerate

Analysis done with

Leica SpiderQC

Application Examples: Leica „Train“-Test

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Leica “Train”-Testrail: Dynamic performance – 20 Hz Velocities

East

UP

North

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Leica “Train”-Testrail: Dynamic performance – 20 Hz Velocities

East

UP

North



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Leica “Test platform”- Dynamic performance – 20 Hz Velocities


Application Examples: Leica „Test Platform“-Test

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Innovative real-time motion detection for various applications

Seismology

co-seismic displacements and waveforms retrieval

Early warning systems

Natural or man-made hazards (volcanic, earth quake / tsunami, fracking, …)

Safety monitoring for infrastructure elements (railways, highways, etc.) close to

potential hazard (landslides, etc.).

Monitoring

Structural and geotechnical engineering monitoring

(buildings, skyscrapers, dams, oil platforms etc.);

Permanent GNSS network reference station “accident” monitoring

Use Cases

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Benefits: Simple - Efficient – Reliable - Robust

Fast, relative displacements at high data rates

Over short intervals of a few minutes, with high accuracy of ~2-4 cm

Fully autonomous - Stand alone receiver – No correction signal needed

Conclusion

Complement to other GNSS solutions for real time displacement detection,

when continuous correction stream cannot be guaranteed

Opens potentially new applications in GNSS structural monitoring

Innovative solution for real-time motion estimation

on-board a stand-alone GNSS receiver

THANK YOU FOR YOUR ATTENTION!

Velocity And Displacement Autonomous Solution Engine

The best answers combine the smartest solutions

When you are interested in high rate and real time cm-level fast motion

detection of an autonomous station, and be independent of any external

reference, the VADASE provides the solution – when it has to be right.

Leica Spider

GNSS Networks and Reference Stations

Smart Solutions from Leica Geosystems

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GNSS Networks and Reference Stations...Innovative Solutions from Leica Geosystems VADASE - Real-time motion estimation on-board a stand-alone GNSS receiver GNSS Networks and Reference