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Briefing for AIAA SOSTC Workshop April 2011 Tobias Nassif, Director SDA

Briefing for AIAA SOSTC Workshop April 2011 Tobias Nassif, Director SDA. What is the Space Data Association?.

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Briefing for AIAA SOSTC Workshop April 2011 Tobias Nassif, Director SDA

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  1. Briefing for AIAA SOSTC Workshop April 2011 Tobias Nassif, Director SDA

  2. What is the Space Data Association? A formal association of satellite operators, established in the Isle of Man which will support the controlled, reliable and efficient sharing of data critical to the safety and integrity of satellite operations Legal framework to protect the sharing of data Physical systems to make data sharing efficient, secure and reliable reducing operators workload and mitigating risks Technical support to ensure operations integrity Shared costs and ‘not-for-profit’ ethos to reduce individual costs

  3. SDA Charter • Seek and facilitate improvements in the safety and integrity of satellite operations through wider and improved coordination between satellite operators • Seek and facilitate improved management of the shared resources of the Space Environment and the RF Spectrum

  4. Why was the SDA created? To improve the accuracy of collision avoidance predictions Expand satellite operator participation Adopt best practices across industry Provide necessary framework for full operations (legal, technical) Address operational issues with current cross-industry conjunction coordination To take advantage of opportunities for other data sharing RFI mitigation, including data for RFI geolocation Company contacts General operations data sharing

  5. Growth of Objects in Space

  6. Who can join the SDA? • The SDA will be run by and for the benefit of satellite operators and the integrity of their operations • Members should be the owners or responsible for the control and orbit operations of in-orbit satellites • Membership is open to all satellite operators in all orbital regimes

  7. Why Join the SDA? • Members will receive secure, reliable and immediate access to accurate information that can help improve their operations • Conjunction assessments • Data for RF Interference analysis and geolocation • Contact information • Ensure the following of best practices and mitigating operational risks • Reduce workload • Automated data conversions for conjunction • Information readily available • Focus on real issues identified by reliable systems • Ensure the use of shared data is controlled and legally protected • Minimize the cost for these critical operations SDA membership will improve the integrity of its members’ satellite operations and that of all satellite operators

  8. SDC – Three Key Mission Areas Initial Operating Capability (IOC) commenced 27 July 2010 • Collision Avoidance (CA) monitoring, maneuver planning & Flight Safety • Radio Frequency Interference mitigation & geolocation support • Authoritative contact information (operations center & POCs) for SDA Member satellites Final Operational Capability (FOC) expected Q1 2011 SDC currently performing Collision Avoidance monitoring for 197 satellites from 13 GEO operators and 114 satellites from 7 LEO operators

  9. Mitigating RF Interference • RFI Increasing; Sources: • Human error (95%) • ASI • Cross-pol / Pwr issues • Terrestrial Rx Issues (1%) • Equipment fault (4%) • Deliberate (tiny %) • Operator actions such as: • Signal analysis • Carrier record checks • Customer checks • Alerts to other operators • Predictive RFI analyses (GEO drifters, LEO) • Geolocation (if available) SDA RFI Service and Alerts • Services such as: • Socrates-GEO • Non-Cooperative Tracking agencies (NCTs) • Commercial collision avoidance services Mitigating Collision Risk • Space is increasingly congested • ITU doesn’t regulate physical space • No integrated CA screening with all best-available data SDA Conjunction Assessment Service SDA’s Role in Industry Issues SDA’s role in Addressing Ops Challenges Typical Mitigation Approach Operational Challenges Causes

  10. SDC Planned CA Process Flow SDC Members contribute and dynamically maintain proprietary satellite maneuver plans, dimensions, status Rectified data and STK analysis scenarios facilitate maneuver avoidance planning & optimization Data stored in common format Members define vehicle-specific conjunction and Neighborhood Watch criteria Conjunctions Analyzed Satellite ephemerides are automatically updated by all SDA members Optional information accumulated for collision threat trending and long-term threat mitigation Conjunctions Alerts Sent SDA Member-unique ephemeris converter created & tested Independent SDC vector comparison & OD verification Data provided on upcoming conjunctions, and contact information to conduct collision threat mitigation Neighborhood Watch Results Sent Non-Cooperative Radar and Optical Tracker-based orbit vectors and/or ephemeris Close Approach Alert notification sent to Members System allows faster investigation of CA events, enabling responsive and accurate threat mitigation

  11. SDC Planned RFI Process Flow SDC Members contribute and dynamically maintain proprietary RF data: Freq plan; polarization; translation freqs; antenna patterns, Rx & Tx chars, beam coverage Data stored in common format Geolocation solution sets generated and sent to Member in format for geolocation system Frequency bands and beam coverages searched for suitable adjacent satellites for geolocation measurements Members contribute data on Reference Emitters/Calibrators Optional information provided to third parties for geolocation or other services Satellite ephemerides are automatically updated by all SDA members Database queried for most likely region, satellite(s), and contact information to investigate potential interference source Members detect an RFI event and report the details to the SDC RFI Alert notification sent to Members System allows faster investigation of RFI events, improving service quality and creating more efficient operations

  12. SDA and Geolocation • Without SDA • Multiple phone calls required • Hours/days required to locate viable solution set and data • Data formats = anyone’s guess • With SDA • Solution sets immediately available • All necessary data centralized and in consistent format • Better data = more accurate results • Geolocation error reduced two orders of magnitude using SDA-on-SDA quality ephemeris • SDA enables faster, more accurate • geolocation results

  13. RFI Geolocation Sample Case 10° Longitude Separation TLE-vs-TLE TLE-vs-SDA SDA-vs-SDA

  14. Potential Future SDA RFI Capabilities • Collect, process, store & disseminate interference details, analyses & solution sets from all sources to enable appropriate investigation, notification and enforcement • both within SDA and with approved external entities • Coordinate data with and for SDA RF experts to identify, analyze, locate, attribute and mitigate interference sources • Develop & maintain RFI mitigation capabilities, procedures and techniques to ensure continuity of operations

  15. Space Population Perigee-vs-Apogee Distribution LEO: GEO:

  16. Space Population and Risk • Spatial density of space objects at GEO higher than at LEO • “Constrained” GEO inclination = contributing factor • Statistics less of interest than actual collision threats!

  17. Why Non-Cooperative Tracking (NCT) is not enough… • Radar & optical tracking good for debris data but may have errors for active satellites • NCTs fit orbit across maneuver(s) • Low thrust, long duration burns common at GEO • Degrades OD sol’n accuracy regardless of orbit theory • “Cross-tagging” • Observations associated with wrong satellite • i.e., multiple satellites in sensor field of view • “Cross-tagging most likely when you need most accuracy” • Caused / compounded by maneuvers during tracking • NCT obs. association independent of OD/theory

  18. Cross-tagging and System Errors • Galaxy-15 anomaly caused westward drift with no maneuvers from April – December 2010 • G15 WAAS intact; orbital position well understood by operator but not in public catalog • Great opportunity to study public data-derived performance • Large cross-tag discontinuity observed 13 Aug • Readily identified as G15/G18 conjunction • Many other such discontinuities observed • Collision risk was never an issue because SDA Members were sharing ephemerides with the SDC

  19. Semi-Major Axis Reveals NCT Discontinuities…

  20. “TLE Detective” Identifies Cross-tags For G15 case, using 2.5σ filter with recursive excision, found that 52 out of 348 (15%) of NCT-derived positional products contain cross-tag or equivalent accuracy degradations

  21. Discontinuities Match Conjunctions…

  22. The Next Steps The SDC has commenced initial operations Final Operational Capability scheduled Q1 2011 The SDA is promoting its services and encouraging all satellite operators to become Members Members can become involved with future requirements, development and testing of the CA and RFI functionality The SDC is expected to evolve and become a major operational system for satellite operators, for safety of flight, and RFI mitigation

  23. IS-6B IS-11 IS-3R 43.00° W 43.25° W 42.75° W IS-6B IS-3R IS-11 Spacing = 184 km Additional NCT Cross-tagging 2008 Comparison Owner ephemeridesPublic Data

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