Abstract:This paper analyzes the LEO constellation’s enhancement effect on GNSS’s precise point positioning(PPP), adopting mathematical simulation technology and taking the GPS system and the Iridium system as examples. Based on the emulational observation data of the GPS and Iridium, taking BJFS station as an example, pseudo- kinematic precise point positioning experiment is performed. The test results show that, compared with the GPS single system, the number of visible satellites of the GPS+Iridium dual system increases by an average of 1.5. The GDOP value and the PDOP value decrease by about 0.25. With Iridium enhanced GPS, the condition number of PPP filtration matrix reduces rapidly and the stability of PPP filtration is promoted; the positioning accuracy of the zenith U-direction, along with the three-dimensional positioning accuracy; the PPP convergence time is shortened by 30% or more and single-difference MW method is adopted to fix the PPP ambiguity. With Ratio =1.5, 3, 5 as an index of ambiguity fixed successfully, and compared with the emulational value of ambiguity, the time required for the first successful fixing of PPP ambiguity is shortened by 40% or more.
ZHAO Xinglong,ZHONG Shiming,OU Jikun et al. Precise Point Positioning Primary Analysis of GNSS Enhanced with LEO Constellation[J]. jgg, 2020, 40(6): 624-628.