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GPS CONSTELLATION STATUS 2004 CGSIC. Captain John Butler 2 SOPS March 2004. Constellation Summary Since Sep 03 CGSIC. 29 operational on-orbit satellites 1 satellite launched (SVN 47: 20 Dec 03) 0 satellite disposed Component changes since Aug 2003
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GPS CONSTELLATION STATUS 2004 CGSIC Captain John Butler 2 SOPS March 2004
Constellation SummarySince Sep 03 CGSIC • 29 operational on-orbit satellites • 1 satellite launched (SVN 47: 20 Dec 03) • 0 satellite disposed • Component changes since Aug 2003 • SVN 23 (No Slot) Switched to Rubidium #2 (Last Clock) • SVN 25 Reaction Wheel #4 shutdown • SVN 36 switched to Cesium #3 • Constellation changes since Aug 2003 • SVN 23 (No Slot) Auto-Track began 5 Feb • SVN 23 (No Slot) Out of Service on 18 Feb
Subsystem Status Bottom Line 18 (1) vehicles are “yellow” (i.e. single string) 8 (1) vehicles are yellow due to bus failures 13 (1) vehicles are yellow due to nav failures
Clocks Bottom Line SVNs 17, 23, 24, 31, and 32 on last clock
Out of Service/Disposal Timeline Proposed IIR-12 Launch 25 May SVN 23 Out of Service Begins 12 Feb Out of Service Decision Point 21 Jun 04 Auto-Track 29 Jan IIR-11 Launch 8 Mar SVN 23 Disposal Window 27 Apr - 20 May Aug 04 Feb 04 Mar 04 Apr 04 May 04 Jun 04 Jul 04 6-Week Removal Process (23)
Constellation Performance All Errors Based on Dual Frequency, Signal in Space Only. Information Presented Reflects Data Collected During the Period from January 1, 2003 to December 31,2003. Thresholds Provided Reflect Average Location Requirements from SPS Signal Specification Dated October, 2001. • PDOP Availability: • Requirement - PDOP of 6 or Less, 98% of the Time or Better • Actual - 99.98385% • Horizontal Service Availability • Requirement - 95% Threshold of 36 meters, 99% of the Time or Better • Actual – 3.66 meters • Vertical Service Availability • Requirement - 95% Threshold of 77 meters, 99% of the Time or Better • Actual – 5.25 meters • User Range Error • Requirement - 6 meters or Less, Constellation Average • Actual - 1.23 meters
Navigation Uploads per Day GPS daily Uploads Count - Calendar Year 2003/2004 60 One Day All Counts One Day Healthy Counts 50 40 # Uploads per Day 30 20 Data Gaps: Jan 11 2003 04:45z - Jan 12 2003 00:00z 10 Feb 22 2003 04:15z - Feb 23 2003 22:45z Data from Boeing Apr 11 2003 17:30z - Apr 12 2003 01:30z SPMA Archives Jun 04 2003 18:00z - Jun 05 2003 00:00z 0 1 31 61 91 121 151 181 211 241 271 301 331 361 26 Day of Year 2003/2004
Current Issues Recent Anomalies • SVN35: Loadshed • SVN56: Unsuccessful SPU swap due to vehicle in Backup Ephemeris mode • SVN23(2): • SVN26: Default nav data due to overwrite of active page • SVN31: Baseband upset • Launch Schedule (based on NLF) • FY03: 2 IIR Accomplished • FY04: 4 IIR, 1 IIR Modified • FY05: 4 IIR Modified • FY06: 2 IIR Modified, 1 IIF Launch Schedule supports continued robust GPS constellation
Summary • Current constellation provides healthy navigation signals • Launches are scheduled to sustain constellation health 2 SOPS continues to ensure GPS performance supports user requirements
Vehicle AgeLaunch through MMD Today 17 (0) Past Design Life 9 (+2) Past Updated MMD
GPS Space and ControlClock and Reaction Wheel Performance Status(as of 1 January 2004) Watch List Clock meets spec watch list dead unused in use Wheel functional watch list dead launch date SVN (PRN) Clock* Wheel 1 2 3 4 1 2 3 4 * II/IIA = Rb, Rb, Cs, Cs IIR = Rb, Rb, Rb Diagonal Line = Unhealthy PLANE A B C D E F 39A(09) 06/93 56R(16) 1/03 41R (14) 11/00 24A (24) 07/91 36A (06) 03/94 51R (20) 05/00 1 SLOT 46R (11)10/99 30A(30) 9/96 33A (03) 03/96 26A (26)07/92 25A (25)02/92 47R(22)12/03 2 40A (10) 07/96 43R(13) 07/97 38A (08) 11/97 44R(28) 07/00 45R (21) 03/03 31A (31) 03/93 3 34A (04) 10/93 35A (05) 08/93 54R (18) 01/01 27A (27) 09/92 32A (01) 11/92 37A (07) 05/93 4 23A (23) 11/90 29A (29) 12/92 13 (02) 06/89 15 (15) 10/90 5 17 (17)12/89 6