THE ALMANAC

摘要

1. "SV Number" refers to space vehicle number. "PRN Number" refers to the satellite's unique pseudorandom noise code. 2. Clock: Rb = rubidium; Cs = cesium. 3. "Launched"and"Usable"datesare based on Universal Time. 4. The current active GPS constellation consists of 4 Block HA satellites, 12 Block HRs, 7 Block IIR-Ms, and 8 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 7 reserve satellites, SVNs 27,32,33, 35,36,37, and 38, and one test satellite, 49, near slots A1, F2-F, C4, B1-F, C2, C1, A3, and B1-F, respectively. SVN35 transmitted signals as PRN03 between September 5 and October 20,2014. The satellite was set unhealthy and not included in broadcast almanacs. 5. The Block IIF-1 through IIF-8 satellites have nicknames Polaris, Sirius, Arcturus, Vega, Canopus, Rigel, Capella, and Spica, respectively. 6. SVN35 and 36 carry onboard corner-cube reflectors for satellite laser ranging (SLR). SLR.