Inter system and inter frequency code biases: simultaneous estimation, daily stability and applications in multi GNSS single frequency precise point positioning
Both inter system and inter frequency code biases (ISCB and IFCB) embodied in the multi GNSS single frequency precise point positioning (MSFPPP) exhibit mainly as systematic errors. Comprehensive analysis of the ISCB and IFCB characteristics and proper assimilation of their impact on MSFPPP are very important. We study the simultaneous estimation of all ISCBs for GLONASS, BDS and Galileo relative to GPS and the IFCBs of GLONASS by using our newly formulated estimable ionospheric weighted MSFPPP model. Then, the daily stability of the ISCBs and IFCBs is examined, on which the application strategy is advised to improve the MSFPPP performance. One month multi GNSS single frequency observation at 60 stations with eight types of receivers is carried out. The results indicate that the ISCBs of Galileo are most stable, followed by GLONASS and BDS, and all ISCBs and IFCBs are sufficiently stable on a daily scale. Imposing this stable information on the MSFPPP model can significantly enhance the model strength and improve the positioning performance.
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