Precise determination of the baseline of the distributed Interferometric Synthetic Aperture Radar (InSAR) satellite system is a prerequisite for completion of scientific missions; however, reliability of the baseline determination is often affected by some unfavorable factors, such as shorter continuous carrier phase tracking arcs of the satellite-borne Global Positioning System (GPS) receiver, few visible GPS satellites from formation flying satellites or low success rate of ambiguity resolution, and frequent orbit maneuvers. In this paper, we try to identify the time when the baseline accuracy is lower by inter-agency comparison, and to improve the accuracy and reliability of the baseline by inter-agency fusion. The GPS observation data of Gravity Recovery and Climate Experiment (GRACE) satellites are processed by the National University of Defense Technology (NDT) and Xi'an Research Institute of Surveying and Mapping (CHS) using different software packages and reduced-dynamic baseline solutions to guarantee independence of the generated baseline products. The results show that inter-agency comparison can be used to identify the time during which the accuracy of the baseline determined by one agency is lower than that of the other. A high consistency is found between results of the NDT and CHS, with Root Mean Square (RMS) being about 0.7, 0.9, 0.7 mm in the radial, along-track, and out-of-plane components, respectively. Around 97.86% of differences between the 3-dimensional GRACE relative position obtained from the NDT and CHS in is less than 2 mm, indicating that there is no obvious systematic deviation between them. Furthermore, it is shown that fusion of the baseline products of the two agencies can reduce the error of random fluctuations, with the precision validated by K/Ka-Band Ranging (KBR) observations of the fused baseline products being improved by 8.97% and 29.21% compared to the NDT and CHS products, respectively.
YI Bin
,
QIN Xianping
,
GU Defeng
,
JU Bing
. Baseline determination for distributed InSAR satellite system using inter-agency comparison and fusion[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2018
, 39(1)
: 321187
-321187
.
DOI: 10.7527/S1000-6893.2017.21187
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