1. GPS Operations CGSIC Brief 15 September 08 Lt Joe Riedesel 2d Space Operations Squadron This briefing is UNCLASSIFIED 1UNCLASSIFIED

2. Overview Navigation and Timing Performance – Navigation Performance – Time Transfer Performance Constellation Status 2UNCLASSIFIED

3. 3

4. UTC TIME TRANSFER Specification 28ns 4UNCLASSIFIED

5. 5 GPS Space and Control Clock and Reaction Wheel Performance Status Wheel functional watch list dead unused 2341 SVN (PRN) 2341 Clock* Wheel * II/IIA = Rb, Rb, Cs, Cs IIR = Rb, Rb, Rb Diagonal Line = Unhealthy launch date Clock meets spec watch list dead unused in use Watch List 39A (09) 06/93 52M (31) 9/06 1 2 SLOTSLOT 3 4 5 PLANE ACDEF 38A (08) 11/97 56R (16 ) 1/03 33A (03) 03/96 59R (19) 03/04 46R (11) 10/99 51R ( 20) 05/00 40A (10) 07/96 43R (13) 07/97 36A (06) 03/94 41R (14) 11/00 44R (28) 07/00 48M (07) 03/08 35A (05) 08/93 37A (**) 05/93 34A (04) 10/93 54R (18) 01/01 32A (**) 11/92 26A (26) 07/92 45R (21) 03/03 6 47R (22) 12/03 30A (30) 9/96 B 60R (23) 06/04 61R (2) 10/99 53M (17) 09/05 25A (25) 02/92 24A ( 24) 07/91 58M (12) 11/06 23A (32) 11/90 55M (15) 10/07 57M (29) 12/07 27A (27) 09/92

6. 19 (+0) SVs past design life 15 (+0) SVs past pre-launch mean life estimate (MLE) 18 (+0) SVs one component away from nav mission failure 8 (+0) SVs one component away from bus failure Anomaly Summary SVN 25 set unhealthy SVN 35 set unhealthy Constellation Status Summary Changes Since Last Update Total SVs in Category 6UNCLASSIFIED

7. 7 IIA Vehicles On Last Clock SVN 36: has a higher likelihood of failing due to its Rb clock being turned on with over 8 years of on-orbit storage SVN-37: being stored as on-orbit spare in LADO SVN-32: being stored as on-orbit spare in LADO Bottom Line: 11 of 15 IIAs left are on their last clock

8. 8 IIR/IIR(M) Clock Status  No IIR/IIR(M) clock failures to date  SVN 43:  First IIR launch, AFS 3 on for test purposes only  SVN 44:  AFS 1 had a baseplate heater failure  Clock is assessed as viable  Performance could be slightly degraded during eclipse season  SVN 61:  AFS 3 clock failure  Switched to AFS 1

9. 9 ACBEDF 80 100 120 160 180 0 20 40 60 GLAN (deg) A3 38 A1 39 B1 56 B3 44 D4 34 D2 46 E3 40 E4 54 F3 43 F1 41 D3 45 E1 51 E2 47 C3 59 F4 60 D1 61 35 A4 27 36 25 24 GPS Locations C4 53 140 37 B2 30 A2 52 Watch List Block IIA Block IIR Block IIR-M Block IIA reserve 58 B4 23 C2 33 C1 57 F2 55 26 IIR-20(M) 48 32 SVN-27 Rephase Start Nov ’08 to b/u SVN-39 SVN-26 Rephase to F5 t/b Complete Apr ’09

10. Geographic Longitude of Ascending Node (GLAN) 0 100 120A CBED F 60 80 180 140 20 40 160 F3 43 26 51 40 54 46 34 35 30 56 44 39 25 38 27 F2 F1 F4 E1 E3 E4 E2 D2 D4 D1 D3 B4 A1 B2 B1 B3 A2 A4 A3 C1 C2 C3 45 47 60 61 53 C4 NOTE: Chart reflects status of bus & navigation payload only (not NDS payload status). FMC PMC NMC Inactive Maneuver OPSCAP 33 59 52 Block SVNs ( # ) IIA 22-40 (14) IIR/IIR-M 41-61 (18) Current IIR-M’s (48, 52, 53, 55, 57, 58) 58 23 24 41 32 36 57 55 37 48

11. Summary Navigation and Timing Performance – Navigation Performance – Time Transfer Performance Constellation Status Questions… 11UNCLASSIFIED