Satellite Orbit and Ephemeris Determination using Inter Satellite Links

Inter Satellite Links6.2.2 IGSO WALKER CONSTELLATION...................................................................................... 1146.2.2.1 Ground Tracking......................................................................................................... 1146.2.2.2 Ground and Inter Satellite Tracking............................................................................ 1156.2.2.3 Ground and Inter Satellite Tracking with Reduced Network...................................... 1156.2.3 IGSO ON THREE LOOPS..................................................................................................... 1176.2.3.1 Ground Tracking......................................................................................................... 1176.2.3.2 Ground and Intersatellite Tracking ............................................................................. 1186.2.4 GEO / IGSO ...................................................................................................................... 1196.2.4.1 Ground Tracking......................................................................................................... 1196.2.4.2 Ground and Intersatellite Tracking ............................................................................. 1216.2.4.3 Ground and Intersatellite Tracking (Regional Network) ............................................ 1236.2.5 PURE LEO CONSTELLATION ............................................................................................. 1256.2.5.1 Ground Tracking with Full Network........................................................................... 1256.2.5.2 Ground Tracking with Reduced Network................................................................... 1266.2.5.3 Ground and Intersatellite Tracking (Reduced Network)............................................. 1276.2.6 GEO / LEO........................................................................................................................ 1286.2.6.1 Ground Tracking (Full Network)................................................................................ 1286.2.6.2 Ground Tracking (Reduced Network) ........................................................................ 1286.2.6.3 Ground and Intersatellite Tracking (Reduced Network)............................................. 1286.2.7 GALILEO 1 (PURE MEO) ................................................................................................... 1306.2.7.1 Ground Tracking......................................................................................................... 1306.2.7.2 Ground and Intersatellite Tracking ............................................................................. 1316.2.8 GALILEO 2 (GEO/MEO).................................................................................................... 1326.2.8.1 Ground Tracking......................................................................................................... 1326.2.8.2 Ground and Intersatellite Tracking (Full Network) .................................................... 1346.3 ACCURACY OF BROADCAST EPHEMERIS (USER EPHEMERIS) ............................................ 1366.3.1 MODEL FITTING ERROR..................................................................................................... 1366.3.2 ORBIT DETERMINATION AND PROPAGATION ERROR ........................................................ 1386.3.3 EPHEMERIS ACCURACY OF SCENARIOS............................................................................ 1486.3.3.1 Optimized GPS ........................................................................................................... 1496.3.3.2 IGSO Walker Constellation ........................................................................................ 1496.3.3.3 IGSO on Three Loops................................................................................................. 1496.3.3.4 GEO / IGSO Constellation.......................................................................................... 1496.3.3.5 Pure LEO Walker Constellation.................................................................................. 1506.3.3.6 GEO / LEO Constellation ........................................................................................... 1506.3.3.7 Galileo Option 1 (Pure MEO)..................................................................................... 1506.3.3.8 Galileo Option 2 (GEO / MEO).................................................................................. 1517 AUTONOMOUS ONBOARD PROCESSING.......................................................................... 1527.1 WHY ONBOARD PROCESSING?.............................................................................................. 1527.2 IMPLEMENTATION ASPECTS OF ONBOARD PROCESSING.................................................... 1547.2.1 COMPLEXITY OF ORBIT PREDICTION AND ESTIMATION ALGORITHMS............................. 1557.2.2 ONBOARD PROCESSING USING ISLS.................................................................................. 1567.3 APPLICATION EXAMPLE: AVAILABILITY DURING ORBIT MANOEUVRES .......................... 1587.3.1 CONTINUED SERVICE DURING MANOEUVRES................................................................... 1607.3.2 FREQUENTLY UPDATED EPHEMERIS CORRECTIONS ......................................................... 1637.4 APPLICATION EXAMPLE: AUTONOMOUS ONBOARD INTEGRITY MONITORING................ 1637.4.1 USER POSITION ERROR DUE TO NORMAL ORBIT AND CLOCK DEGRADATION ................. 1687.4.2 USER POSITION DEGRADATION DUE TO UNFORESEEN ORBIT MANOEUVRE .................... 172R. 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