NASA/CR‐2005‐213693 GPS Lessons Learned from the International Space Station, Space Shuttle and X‐38 John L. Goodman United Space Alliance Houston, Texas November 2005 The NASA Scientific and Technical Information Program Office ... in Profile Since its founding, NASA has been dedicated to the • CONFERENCE PUBLICATION. Collected advancement of aeronautics and space science. The papers from scientific and technical NASA Scientific and Technical Information (STI) conferences, symposia, seminars, or other Program Office plays a key part in helping NASA meetings sponsored or co-sponsored by maintain this important role. NASA. • SPECIAL PUBLICATION. Scientific, The NASA STI Program Office is operated by technical, or historical information from Langley Research Center, the lead center for NASA’s NASA programs, projects, and missions, scientific and technical information. 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Goodman United Space Alliance Houston, Texas National Aeronautics and Space Administration Johnson Space Center Houston, Texas 77058 November 2005 Available from: NASA Center for AeroSpace Information National Technical Information Service 7121 Standard Drive 5285 Port Royal Road Hanover, MD 21076‐1320 Springfield, VA 22161 This report is also available in electronic form at http://ston.jsc.nasa.gov/collections/TRS Table of Contents 1. Acronyms 9 2. Preface 13 3. Introduction 15 4. The Software Nature of Satellite Navigation 17 Threats to Integrity 17 Software Quality and GNSS Integrity 17 Computer Integration Versus Plug and Play 19 5. GPS Lessons Learned 21 Mission Impacts of GPS Problems 22 Define Realistic Schedule, Budget, and Requirements 23 Off-The-Shelf Versus Development 24 Working With Off-The-Shelf Items 26 Take Advantage Of Lessons Learned 28 Do Not Take Shortcuts With Process 28 Lab and Flight Testing 30 Provide the Vendor With As Much Data As Possible 34 Integrated Teams 35 The Challenge Of Being A New User 38 Documentation 39 Design Insight 40 Independent Verification and Validation 42 Orbit Determination Accuracy 43 COTS Box Outputs May Not Be Designed With Redundancy Management In Mind 45 Do Not Totally Rely On The Vendor For Navigation Expertise 45 Vulnerability to Space Radiation 46 The Challenge of Autonomous, On-Board Navigation 46 Navigation Conferences 47 6. International Space Station 49 ISS Space Integrated GPS/INS 49 Ground Testing and Shuttle Flight Tests of ISS SIGI 51 SIGI Flight Experience on the ISS 51 ISS Spacecraft Position Optimal Tracking (SPOT) Filter 53 SIGI Software and ISS Telemetry Changes 54 Other GPS Receivers on the ISS 55 5 of 118 Table of Contents Continued 7. The Space Shuttle and GPS 57 Overview of Space Shuttle Navigation System 58 Integrating GPS In A Loosely Coupled Architecture 59 The Tightly Coupled Option 60 State Replacement Chosen 61 Receiver Selection 63 GPS Antennas 64 Initial Flight Tests and Receiver Missionization 64 “Single String” TACAN Replacement Flight Tests 66 Status of Shuttle TACAN Replacement 72 Mission Control and On-Board, Operational Use of GPS By Flight Phase 73 Differential GPS and the Space Shuttle 85 8. Other GPS Receivers On The Space Shuttle 87 Relative GPS Demonstrations 87 Scientific Payload Support 88 Preparation for Future Autonomy Demonstration 88 9. Shuttle Space Integrated GPS/INS 89 Tightly Coupled Integration 89 Shuttle Space Integrated GPS/INS 89 Shuttle SIGI Ground and Flight Test Results 90 10. X-38/Crew Return Vehicle 93 V-201 Flight Test 93 X-38 Design 93 CRV GPS Unit 94 CRV SIGI Ground and Flight Testing 95 Resolving the SIGI Attitude Initialization Issue 96 V-201 SIGI Operations Concept 97 11. Rationale Behind a Notional Shuttle GPS Receiver Upgrade 99 Receiver Recovery 100 Loss of Service 100 New GPS Signals 100 Receiver Autonomous Integrity Monitoring and Satellite Based Augmentation 101 Shuttle Autoland Using Ground Based GPS Augmentation 102 Weather Minimums For Landings 103 Simplification of Shuttle Navigation Procedures 103 Precision Orbit Determination 104 Rendezvous and Proximity Operations 104 6 of 118 Table of Contents Concluded Attitude Determination 105 GPS Metric Tracking For Range Safety 105 12. Summary 107 13. References 109 Figures 1. ISS GPS Antenna 49 2. ISS Antenna Array Location 50 3. Shuttle and TACAN Ground Station 57 4. Shuttle Single and Three String Architectures 62 5. Shuttle Receiver Selection Timeline 63 6. Location of Single String Antennas 65 7. Location of Three String Antennas 65 8. STS-88 GPS Velocity Noise 68 9. Geographic Distribution of Ionospheric Scintillation 69 10. Receiver Data From STS-110 Entry (April 2002) 70 11. GPS States Compared With Best Estimate of Trajectory During Entry 71 12. Use of Mission Control GPS Filter 76 13. Day of Rendezvous Profile 79 14. Entry Navigation Sensors 81 15. Mission Control Use of Single String GPS 83 16. Martin Marietta X-24A 93 17. X-38 V-132 Drop Test 94 18. X-38 GPS Antenna and Camera Locations 94 19. X-38 Drop Test at Edwards Air Force Base 95 20. SIGI Testing at Dryden Flight Research Center 96 21. Advantages of a Modern GPS Receiver 99 22. Upcoming Enhancements to Global Navigation Satellite Systems 101 Tables 1. GPS Flights on the Shuttle and Shuttle Payloads 21 2. Lessons From Other Programs 29 3. Shuttle and Progress Missions Related to ISS SIGI 51 4. Operational Impacts of SIGI Induced ISS Computer Crash 52 5. Planned TACAN Phase-Out From Federal Radionavigation Plan 57 6. Legacy Space Shuttle Navigation Sensors 59 7. X-38 SIGI Flight Test Program on the Shuttle 95 7 of 118 This page intentionally left blank. 8 of 118 1. Acronyms EGNOS ‐ European Geostationary Navigation AERCam ‐ Autonomous Extravehicular Overlay Service Robotic Camera FDIR –Fault Detection Identification and ATLAS ‐ Atmospheric Laboratory for Reconfiguration Applications and Science FOM –Figure Of Merit ATV –Automated Transfer Vehicle GANE –GPS Attitude and Navigation BET –Best Estimate of Trajectory Experiment BFS –Back‐up Flight System GDOP –Geometric Dilution of Precision BIT –Built In Test GEM –GPS Embedded Module BITE –Built In Test Equipment GFE – Government Furnished Equipment CANDOS ‐ Communications And Navigation GLONASS ‐ Global Navigation Satellite Demonstration On Shuttle System CHAMP ‐ CHAllenging Minisatellite Payload GNC –Guidance, Navigation and Control COAS – Crew Optical Alignment Sight GNSS –Global Navigation Satellite Systems COTS –Commercial Off The Shelf GPC – General Purpose Computer CRISTA‐SPAS – CRyogenic Infrared GPS –Global Positioning System Spectrometers and Telescopes for Atmospheric – Shuttle PAllet Satellite GRACE ‐ Gravity Recovery And Climate Experiment CRV – Crew Return Vehicle HAINS –High Accuracy Inertial Navigation DART – Demonstration of Autonomous System Rendezvous Technology HHL –Hand Held Laser DPS –Descent Propulsion System HTV ‐ H‐II Transfer Vehicle DTO – Detailed Test Objective HUD –Heads Up Display EGI –Embedded GPS/INS ICD – Interface Control Document 9 of 118 IMU – Inertial Measurement Unit PASS –Primary Avionics Software Subsystem INS – Inertial Navigation System PRN ‐ Pseudorandom Noise Code ISS – International Space Station QA –Quality Assurance IV&V – Independent Verification and RAIM –Receiver Autonomous Integrity Validation Monitoring JSC –Johnson Space Center RLG –Ring Laser Gyro JPALS ‐ Joint Precision Approach and Landing RM –Redundancy Management System SA, S/A –Selective Availability KSC – Kennedy Space Center SEM‐E ‐ Standard Electronic