Validation Of GNSS/LEO Satellites Precise Orbits Based On SLR Data

Satellite Laser Ranging(SLR),which can directly obtain the sub-centimetre level of range measurement,is the unique space geodetic technology without ambiguity.It is the most reliable means to validate the orbit precision of GNSS,LEO and other geodetic satellite.In this paper,the precise orbit of GPS36,GLONASS,and GRACE are validated by using SLR normal points data,and the distribution of the observed values and residuals are analyzed in time and space.The specific work of this paper are as follows:The 12-year GPS 36 satellite and GLONASS satellites presice orbits for the full year of 2015 are validated by SLR normal points data.And the 12 years GPS36 satellite SLR validation results show that GPS36 satellite orbit accuracy overall is better than 4cm and SLR laser observation accuracy for GPS36 satellite is about 1cm,but a clear systematic error and periodic disturbance are found in these results.The GLONASS satellites’ SLR validation results show that GLONASS satellites orbit accuracy is better than 3.3cm,the accuracy of SLR observation is better than 1.2cm overall.Except some systermatic errors,the results still show that the quality of validated residuals is related to the satellite servise life.The 8-year of reduced-dynamic orbit and 12-year of zero-difference kinematic orbit for GRACE satellites are validated by using SLR.The accuracy of the GRACE satellite reduced-dynamics orbit at 7090 and 7810 stations was better than 1.3 cm and 1.7 cm respectively.The zero-difference kinematic orbits’ accuracy is better than 2.5cm for GRACE-A and 2.7cm for GRACE-B.The both types of orbits have hardly systematic error,and The GRACE kinematic orbits’ residuals of each site obey normal distribution.The number of SLR data is inversely proportional to the observed elevation angle,and the geometric distribution of spatial observation points has a periodicity of π at different azimuth angles.The SLR observation data provided by EDC is better than CDDIS in integrity and continuity,and the RMS scatter distribution of residual values are basically the same.The results show that the two agencies have good consistency with the SLR observation data.EDC has more effective observations than CDDIS significantly,it shows that the SLR observations provided by EDC is more abundant than CDDIS.Using GLONASS satellite SLR data as an example,the residual analysis is carry out about the three coordinate components in the station coordinate system,the earth fixed coordinate system and the satellite RTN coordinate system.The results show that,the systematic error of the residuals is not obvious in the three components of each coordinate system.In addition,this paper also studied the satellite orbit affected in the eclipse period and verified all day long daily observations number of different period observation quality analysis by SLR.The results show that,residual scatters distribution are obviously spare during the eclipse period and before or after the eclipse period,and the validated residuals become larger.The results show that,the satellite orbit precision becomes worse during the eclipse period,and the SLR data can be used to validate the influence of the eclipse period on satellite orbit effectively.