Upload
mohan-matli
View
137
Download
5
Embed Size (px)
Citation preview
Slide 1
Simulation, Test and Verification of SHEFEX-2 Hybrid Navigation System
Dr. Stephan Theil (DLR Institute of Space Systems, Bremen, Germany)Dr. Andreas Himmler (dSPACE GmbH Paderborn, Germany)Stephen Steffes, Malak Samaan and Michael Conradt(DLR Institute of Space Systems, Bremen)
Slide 2
SHEFEX2
Slide 3
HNS Motivation
Some passenger experiments require attitude accuracy of 0.17° at entryOnboard navigation system
Equipped with decoupled GPS and IMUIMU (ISI DMARS-R) can achieve 0.3° alignment accuracyHigh vibrations cause the INS to drift 3° before entry
Hybrid navigation system is developed to meet the needs of the passenger experiments by fusing GPS, IMU and Star Tracker measurements
Slide 4
Flight Profile
Slide 5
Sensors
Inertial Measurement Unit (IMU)iIMU-FCAI-MDS3 fiber optical gyros and 3 servo-accelerometersGyro: 1°/hr bias, 0.03°/√hrAccel: 2mg bias, 50μg/√Hz
GPS ReceiverPhoenix-HD receiverPVT Accuracy: 2-50m, 0.05m/s
Star Tracker (STR)Developed by DLR Bremen3-axis attitude accuracy: 0.1°
Slide 6
Slide 7
Hybrid Navigation System Concept
STR
GPS
IMUState
Integration
KF Update
KF Propagate
Internal Clock
Acquisition Aiding
Attitude @2Hz
Trigger @2Hz
Trigger @500Hz
PPS
ΔV, Δθ @500Hz
Pos, Vel, Time @1Hz
Pos, Vel @1Hz
Δt @500HzGPS, STR Times
Error estimates
Nav solution
Δt, ΔV, Δθ
Pos, Vel, Att
Navigation Filter
Navigation Computer
Slide 8
Software Simulation
Purpose: test functionality, measure system performance, stress the system, debugMATLAB®/Simulink® is an excellent simulation tool and provides good visibility of models and flight code
Simulation SetupUsing nominal flight dynamics from rocket developerContains high fidelity models of IMU, GPS and Star Tracker
Generic models of IMU and Star Tracker with instrument specific parametersGPS model specifically designed to model Phoenix-HD
Flight software embedded with s-function
Slide 9
Hardware-In-the-Loop Testing
Purpose: test interfaces, test unmodeled instrument details, use real time, debugdSPACE allows model development using Simulink, provides hardware API, range of hardware interfacesControlDesk provides visibility of dSPACE simulation
Hardware-In-the-Loop SetupSpirent GSS7700 simulates analog GPS antenna input3-axis rotation table simulates flight rotations for IMUJenoptik Optical Sky Stimulator provides images for star tracker camera
Hardware testing is done in 4 phasesProgressively swapping software model for flight hardware
Slide 10
dSPACE
HNS hardware-in-the-loop setup:Main processor board (DS1006)
Controls mission and instrument simulationsSynchronizes to external trigger
Digital interface board (DS2202)Interface to external TTL signals
Serial interface board (DS4201)Serial interface for all sensor models
Ethernet interface board (DS4504)Remote trajectory to Spirent GPS simulator
Scramnet interface board (DS4503)Rotation table control
Slide 11
Slide 12
Slide 13
Slide 14
Slide 15
Benefits of Using dSPACE
Modular system for all sizes of hardware-in-the-loop systemsProduct range: from component test systems up to turn-key integration test systemsBased on full range of product-level componentsAny customer-specific solutions, if requiredEasy to configure, upgrade and adaptWorldwide support by local engineers in major countries
Slide 16
Working with dSPACEReal-Time Interface – RTI
Automatic implementation of MATLAB®/Simulink®/Stateflow®
models on dSPACE hardwareGraphical configuration of all I/O interfaces in the Simulink® block diagramAutomatic real-time code generation from the block diagram and download to the dSPACE prototyping hardwareEasy and safe to use due to automatic consistency checks
Slide 17
Working with dSPACE: ControlDeskManaging and Instrumenting Experiments
Creation of virtual instrument panels by drag & dropReal-time data capture and online parameter tuningGraphical experiment and hardware managementEasy access to all model variables
Slide 18
Software Simulation Results
Quick simulation development due to Matlab/Simulink heritageModels were kept modular to easily reuse in dSPACE simulationNavigation flight code wrapped in s-function and seamlessly integrated
On-going development and testing
Initial software performance results:
Slide 19
Slide 20
Slide 21
Slide 22
Hardware-In-the-Loop Development
Quick dSPACE simulation development due to model reuseMinor problems synchronizing dSPACE with SpirentCustom software needed for Optical Sky Simulator to remotely control image in real timeRotation table control not yet implemented
HNS hardware interface software still under development
Slide 23
Conclusions & Outlook
Status:On-going H/W integration and testingH/W delivery in June 2010Launch expected in winter 2011
Expected results:Confirmation of predicted performanceRecorded flight data for further development
Goal:Develop autonomous Hybrid Navigation System for sounding rockets, hypersonic flight and space transportation systems