GPS World, August 2015

THE ALMANAC Orbit Data and Resources on Active GNSS Satellites GPS Constellation SVN PRN CLOCK LAUNCHED USABLE PLANE SLOT NOTES 23 32 Rb 11 26 90 2 26 08 E5 26 26 7 7 92 A 34 04 Rb 10 26 93 11 22 93 D6 B 40 10 7 16 96 C 38 08 11 6 97 D 43 13 Rb 7 23 97 1 31 98 F2 F E 46 11 Rb 10 7 99 1 3 00 D2 F 51 20 Rb 5 11 00 6 1 00 E7 F 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 45 21 Rb 3 31 03 4 12 03 D3 47 22 Rb 12 21 03 1 12 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 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 66 27 Rb 5 15 13 6 21 13 C2 64 30 Rb 2 21 14 5 30 14 A3 G 67 06 Rb 5 17 14 6 10 14 D4 G 68 09 Rb 8 2 14 9 17 14 F3 G 69 03 Rb 10 29 14 12 12 14 E1 71 26 Rb 3 25 15 4 20 15 B1 F 72 08 Cs 7 15 15 C3 H LAUNCH OF GPS IIF 10 on July 17 Photo ULA GPS Satellite System Information See details on page 49 National Executive Committee for Space Based Positioning Navigation Timing www gps gov governance excom DoD GPS Operations Center and 2SOPS Constellation Status https gps afspc af mil gpsoc https gps afspc af mil gps U S Coast Guard Navigation Center Navigation Information Service NIS www navcen uscg gov General Notes TYPE Block IIA TYPE Block IIR 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 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 3 Block IIA satellites 12 Block IIRs 7 Block IIR Ms and 9 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 6 reserve satellites SVNs 27 32 35 36 37 and 38 and one test satellite 49 near slots A1 F2 F B1 F C2 C1 A2 and B1 F respectively SVN27 transmitted signals as PRN26 Feb 27 March 13 2015 SVN32 transmitted signals as PRN26 Feb 5 24 2015 SVN38 continued to transmit signals as PRN08 until April 14 2015 SVN49 transmitted signals as PRN08 April 30 July 1 2015 The satellites were not set healthy and with the exception of SVN38 were not included in the broadcast almanacs SVN38 was transitioned into the broadcast almanacs on Jan 7 2015 5 The Block IIF 1 through IIF 9 satellites have nicknames Polaris Sirius Arcturus Vega Canopus Rigel Capella Spica and Deneb respectively 6 SVN35 and 36 carry onboard corner cube reflectors for satellite laser ranging SLR SLR tracking of the satellites permitted 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 Jan 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 Performance Notes A SVN26 PRN26 was set unusable on Jan 5 2015 beginning at 17 50 UTC and removed from the constellation on Jan 6 2015 It was placed into a graveyard orbit around Feb 25 2015 B SVN34 PRN04 slot number has been redisignated as D6 C SVN40 PRN10 was removed from the active GPS constellation on July 16 2015 D SVN38 PRN08 was removed from the active GPS constellation on Oct 30 2014 Although set unhealthy it continued to transmit L band signals as PRN08 On Jan 7 2015 it was transitioned into the broadcast almanacs but remained set unhealthy SVN38 was removed from the constellation on March 26 2015 and stopped transmitting L band signals on April 14 2015 It remains a reserve satellite now located near slot A2 E SVN43 PRN13 was re phased to slot F2 F between about Sept 21 2014 and Jan 12 2015 F SVN51 PRN20 was re phased to slot E7 between E3 and E4 between Dec 17 2014 and June 28 2015 Due to limitations in official GPS orbit nomenclature slot E7 is currently also referred to as slot B6 G The slot numbers of SVN64 PRN30 SVN67 PRN06 and SVN68 PRN09 have been redesignated as A3 D4 and F3 respectively H SVN72 will operate as PRN08 from slot C3 replacing SVN59 PRN19 which will reportedly become a reserve satellite GPS World August 2015 www gpsworld com 46