GPS World, August 2013

Orbit Data and Resources on Active GNSS Satellites ALMANAC THE GPS Constellation SV PRN CLOCK LAUNCHED USABLE PLANE SLOT NOTES TYPE Block IIA 23 32 Rb 11 26 90 2 26 08 E5 26 26 Rb 7 7 92 7 23 92 F2 F 39 09 Cs 6 26 93 7 20 93 A5 A 35 30 8 30 93 B 34 04 Rb 10 26 93 11 22 93 D4 36 06 Rb 3 10 94 3 28 94 C6 C 33 03 Cs 3 28 96 4 9 96 C5 D 40 10 Cs 7 16 96 8 15 96 E6 38 08 Cs 11 6 97 12 18 97 A3 TYPE Block IIR 43 13 Rb 7 23 97 1 31 98 F3 46 11 Rb 10 7 99 1 3 00 D2 F 51 20 Rb 5 11 00 6 1 00 E1 44 28 Rb 7 16 00 8 17 00 B3 41 14 Rb 11 10 00 12 10 00 F1 54 18 Rb 1 30 01 2 15 01 E4 56 16 Rb 1 29 03 2 18 03 B1 A SV PRN CLOCK LAUNCHED USABLE PLANE SLOT NOTES 45 21 Rb 3 31 03 4 12 03 D3 47 22 Rb 12 21 03 12 1 04 E2 59 19 Rb 3 20 04 4 5 04 C3 60 23 Rb 6 23 04 7 9 04 F4 61 02 Rb 11 6 04 11 22 04 D1 TYPE Block IIR M 53 17 Rb 9 26 05 12 16 05 C4 52 31 Rb 9 25 06 10 12 06 A2 58 12 Rb 11 17 06 12 13 06 B4 55 15 Rb 10 17 07 10 31 07 F2 A 57 29 Rb 12 20 07 1 2 08 C1 48 07 Rb 3 15 08 3 24 08 A4 50 05 Rb 8 17 09 8 27 09 E3 TYPE Block IIF 62 25 Rb 5 28 10 8 27 10 B2 63 01 Rb 7 16 11 10 14 11 D2 A 65 24 Cs 10 4 12 11 14 12 A1 E 66 27 Rb 5 15 13 6 21 13 C2 F General Notes Performance Notes 1 SV Number refers to space vehicle number PRN Number refers to the satellites unique pseudorandom noise code 2 Clock Rb rubidium Cs cesium 3 Launched and Usable dates are based on Universal Time 4 The current active GPS constellation consists of 8 Block IIA satellites 112 Block IIRs 7 Block IIR Ms and 4 Block IIFs for a total of 31 satellites and is under FOC Full Operational Capability The constellation is in the 24 3 or Expandable 24 configuration with satellites occupying the fore and aft bifuracted slots in the B D and F planes There are currently five reserve satellites SVNs 27 32 35 37 and 49 near slots A1 F2 F B1 F C1 and B1 F respectively SVN49 transmitted signals as PRN27 between October 18 2012 and March 13 2013 and again as PRN27 between March 28 and May 9 2013 It started transmitting signals as PRN30 on May 9 2013 It continued to be set unhealthy and is not incuded in broadcast almanacs 5 The Block IIF 1 2 3 and 4 satellites have nicknames Polaris Sirius Arcturus and Vega respectively 6 SVN35 and 36 carry onboard corner cube reflectors for satellite laser ranging SLR SLR tracking of the satellites permits analysts to differentiate between onboard clock errors and satellite ephemeris errors in GPS tracking 7 Selective availability SA was set to zero on all satellites by presidential order on May 2 2000 at approximately 4 00 UT Previous Almanacs provide a history of SA status 8 Antispoofing AS was activated on January 31 1994 on all Block IIs AS is occasionally off for testing and other purposes Previous Almanacs provide a history of AS status 9 The design life and mean mission duration goals of the Block IIA IIR and IIF satellites are 75 and 6 years 10 and 75 years and 12 and 99 years respectively 10 GPS World believes this information to be correct as of press time However because of the satellite constellations evolving nature readers should contact GPS information services listed on these pages for more current data 11 Dr Richard Langley of the University of New Brunswick provided the GPS satellite status information and compiled the notes A SVN39 PRN09 is being moved from orbit slot A1 to A5 B SVN35 PRN30 was set unusable on March 28 2013 and decommissioned from active service on May 1 2013 C SVN36 PRN06 orbit slot designation switched from C5 to C6 D SVN33 PRN03 orbit slot designation switched from C2 to C5 E SVN65 PRN24 active clock set to Cs3 before being set healthy Orbit slot designated as A1 F SVN66 PRN27 launched on May 15 2013 at 21 38 UTC GPS Satellite System Information National Executive Committee for Space Based Positioning Navigation Timing www gps gov governance excom The EXCOM advises senior national government leadership and coordinates with federal agencies about policy matters concerning GPS its augmentations and related systems The deputy secretaries of Defense and Transportation jointly chair the EXCOM The National Space Based PNT Advisory Board operates in an independent advisory capacity for the EXCOM as directed by the National PNT Policy and in accordance with the Federal Advisory Committee Act For information contact National Coordination Office for Space Based PNT Herbert C Hoover Building Rm 2518 1401 Constitution Ave NW Washington D C 20230 phone 202 482 5809 fax 202 482 4429 e mail pnt office@ gps gov DoD GPS Operations Center and 2SOPS Constellation Status https gps afspc af mil gpsoc https gps afspc af mil gps The U S Department of Defense DoD GPS Operations Center and the 2nd Space Operations Squadron 2SOPS U S Air Force maintain Internet sites for military and DoD users The GPS Operations Center provides DOP predictions performance assessments anomaly impact analysis FAQs and other services for GPS users in the field 2SOPS operates a GPS Constellation Status site with scheduled outages user advisories almanac data electronic mail and downloadable files For more information Military Contact GPS Operations Center at DSN 560 2541 U S Coast Guard Navigation Center Navigation Information Service NIS www navcen uscg gov This site offers GPS constellation status scheduled outage updates user advisories and almanac data as well as Differential GPS and Coast Guard Local Notice to Mariners information Voice recording for GPS constellation status 703 313 5907 For more information Contact the NIS Watchstander 24 hours a day at phone 703 313 5900 fax 703 313 5920 or e mail tis pf nisws@ uscg mil THE GPS III satellite www gpsworld com August 2013 GPS World 47