s=vt(pseudorange) 3. Space Segment S: range v:light velocity seudorange receiver 3.1 Constellation t: time o GPS Nearly circular orbits s=t Ea(i)b(i)cos( o)(carrier phase) Altitude of about 20200 km s: range 24-hour worldwide coverage phase of electronic magnetic wave Time -21+3 satellites in six orbital planes (A to Et Carrie ase receiver Four satellites per plane. Furthermore, four active spare Frequencies: L1,L2 Coordinate This constellation provides global coverage with four to eight simultaneously observable satellites above 15 Single frequencies receiver System elevation at any time of day ency receive Receiver -I0, occasionally up to 10 satellites visible; 3.2 GPS Satellites -5. occasionally 12 satellites visible. 1. General Remarks he GPs satellites. essentially provide a platform for radio transceivers. atomic clocks. commuters, and various ancillary The auxiliary equipment of each satellite I Solar panels for power supply 2. A propulsion system for orbit adjustments and stability control The satellites have various systems of aunch ☆BcCK Assigned pseudorandom noise(PRN)code Orbital position number NASA catalogue number, and International designation. Satellite Categories GPS Satellites Block ll Cont. Block IIR, IIF Total: 8 GPS Satellites Block I Orbital 10Jun8912J89 1617Aug8 Sep 89 151921ot8914Nov89 26 Apr 0 16 May 80 10 Dec 90 Wheel 126.8 31Aug90 BBAD ep 84 3 Oct 84 18 Nov 95 Clock Oct90 20 act90 9 Oct 85 30 Oct 85 27 Fcb 94 Signal 99.92 GPS Satellite GPS Receiver Time System Coordinate System s= v t (pseudorange) s: range v: light velocity t: time s= t Σa(i) b(i) cos(ϕ) (carrier phase) s: range ϕ : phase of electronic magnetic wave t: time Frequencies: L1, L2 Single frequencies receiver Dule frequency receive Carrier Phase receiver Pseudorange receiver 3. Space Segment – Nearly circular orbits – Altitude of about 20200 km – 24-hour worldwide coverage. – 21 + 3 satellites in six orbital planes (A to F) – An inclination of 55° – Four satellites per plane. Furthermore, four active spare satellites for replenishment will be operational. This constellation provides global coverage with four to eight simultaneously observable satellites above 15° elevation at any time of day. 3.1 Constellation –10°, occasionally up to 10 satellites visible; –5°, occasionally 12 satellites visible. 1. General Remarks The GPS satellites, essentially, provide a platform for radio transceivers, atomic clocks, computers, and various ancillary equipment used to operate the system. The auxiliary equipment of each satellite 1. Solar panels for power supply 2. A propulsion system for orbit adjustments and stability control. 3.2 GPS Satellites The satellites have various systems of identification: – Launch sequence number, – Assigned pseudorandom noise (PRN) code, – Orbital position number, – NASA catalogue number, and – International designation. Satellite Categories Cont. – Block I – Block II, IIA – Block IIR, IIF GPS Satellites Block I Total: 10 11 03 9 Oct 85 30 Oct 85 27 Feb 94 Signal 99.9 10 12 8 Sep 84 3 Oct 84 18 Nov 95 Clock 133.5 9 13 13 Jun 84 19 Jul 84 25 Feb 94 Power 115.2 8 11 14 Jul 83 10 Aug 83 4 May 93 Power 116.8 7 --- 18 Dec 81 ---- Booster --- 6 09 26 Apr 80 16 May 80 10 Dec 90 Wheels 126.8 5 05 9 Feb 80 27 Feb 80 28 Nov 83 Wheels 45.0 4 08 11 Dec 78 8 Jan 79 27 Oct 86 Clock 93.6 3 06 6 Oct 78 9 Nov 78 19 Apr 92 Clock 161.3 2 07 13 May 78 14 Jul 78 30 Aug 80 Clock 25.5 Operation (Months) Reason of loss Loss of navigation Available since Launch date Flight PRN No. No. GPS Satellites Block II Cont. Total: 8 20 15 1 Oct 90 20 act 90 D2 19 21 2 Aug 90 31 Aug 90 E2 18 20 25 Mar 90 19 Apr 90 B2 17 18 24 Jan 90 14 Feb 90 F3 16 17 11 Dec 89 11 Jan 90 D3 15 19 21 Oct 89 14 Nov 89 A4 14 16 17 Aug 89 13 Sep 89 E3 13 02 10 Jun 89 12 Jul 89 B3 Orbital position Available since Launch date Flight PRN No. No