Satellite clock offset estimation and analysis based on arc-wise observation files

In order to meet the demand of GPS real/near real time (RT/NRT) application, it is proposed that a clock estimation algorithm with high reliability and adequate accuracy, which is based on arc-wise observation data gained by merging hourly files or 15-min files offered by IGS. It is analyzed emphatically that the critical influence factors of the algorithm, and account the efficacy of the algorithm. Test indicates that lengths of the observation arc, precision of the obit, ERP and station number are all the important influence factors of the novel algorithm. When the observation arc is set as 24h, 12h, 6h, 3h, 1h, 0.5h and the station number is 120, STD of the clock offset is 0.05ns, 0.11ns, 0.19ns, 0.22ns, 0.27ns, 0.29ns, while the STD of the clock offset decreases by 100%, 73%, 47%, 48%, 52%, 58% when the station number is reduced by half, what's more the STD of the clocks decreases by 120%, 27%, 5%, 4%, 4%, 7% as the precision of orbit decreases.

I. Introduction (Heading 1)

The development of GPS real/near real time (R T /NR T) application puts forward higher requirement in terms of reliability and timeliness on GPS products. Some certain geodetic missions, such as real time precise point positioning (RTPPP), GPS meteorology and atmospheric sounding, may require real/near real time GPS orbit and clock products within the desired time frame and with adequate accuracy.