The Wide-Lane(WL)and Narrow-Lane(NL)Uncalibrated Phase Delays(UPDs)are the prerequisites in the traditional Precise Point Positioning(PPP)Ambiguity Resolution(AR).As the generation mechanism of various biases becomes ...The Wide-Lane(WL)and Narrow-Lane(NL)Uncalibrated Phase Delays(UPDs)are the prerequisites in the traditional Precise Point Positioning(PPP)Ambiguity Resolution(AR).As the generation mechanism of various biases becomes more complex,we systematically studied the impact factors of four satellite systems WL and NL UPDs from the perspective of parameter estimation.Approximately 100 stations in a global network are used to generate the UPDs.The results of different satellite systems show that the estimation method,update frequency,and solution mode need to be treated differently.Two regional networks with different receiver types,JAVAD,and Trimble,are also adopted.The results indicate that the receiver-dependent bias has an influence on UPD estimation.Also,the hardware delays can inhibit the satellite-side UPDs if these receiver-specific errors are not fully deployed or even misused.Furthermore,the temporal stability and residual distribution of NL UPDs are significantly enhanced by utilizing a regional network,with the improvements by over 68%and 40%,respectively.It demonstrates that different network scales exhibit the different implication of unmodeled errors,and the unmodeled errors cannot be ignored and must be handled in UPD estimation.展开更多
The Haiyang-2D altimetry mission of China is one of the first Low Earth Orbit(LEO)satellites that can receive new B1C/B2a signals from the BeiDou-3 Navigation Satellite System(BDS-3)for Precise Orbit Determination(POD...The Haiyang-2D altimetry mission of China is one of the first Low Earth Orbit(LEO)satellites that can receive new B1C/B2a signals from the BeiDou-3 Navigation Satellite System(BDS-3)for Precise Orbit Determination(POD).In this work,the achievable accuracy of the single-receiver ambiguity resolution for onboard LEO satellites is studied based on the real measurements of new BDS-3 frequencies.Under normal conditions,six BDS-3 satellites on average are visible.However,the multipath of the B1C/B2a code observations presents some patchy patterns that cause near-field variations with an amplitude of approximately 40 cm and deteriorate the ambiguity-fixed rate.By modeling those errors,for the B2a code,a remarkable reduction of 53%in the Root Mean Square(RMS)is achieved at high elevations,along with an increase of 8%in the ambiguity-fixed rates.Additionally,an analysis of the onboard antenna’s phase center offsets reveals that when compared to the solutions with float ambiguities,the estimated values in the antenna’s Z direction in the solutions with fixed ambiguities are notably smaller.The independent validation of the resulting POD using satellite laser ranging at 16 selected high-performance stations shows that the residuals are reduced by a minimum of 15.4%for ambiguity-fixed solutions with an RMS consistency of approximately 2.2 cm.Furthermore,when compared to the DORIS-derived orbits,a 4.3 cm 3D RMS consistency is achieved for the BDS-3-derived orbits,and the along-track bias is reduced from 2.9 to 0.4 cm using ambiguity fixing.展开更多
基金This study is sponsored by the National Natural Science Foundation of China(U20B2056,42004014,41974001)the Natural Science Foundation of Jiangsu Province(BK20200530).
文摘The Wide-Lane(WL)and Narrow-Lane(NL)Uncalibrated Phase Delays(UPDs)are the prerequisites in the traditional Precise Point Positioning(PPP)Ambiguity Resolution(AR).As the generation mechanism of various biases becomes more complex,we systematically studied the impact factors of four satellite systems WL and NL UPDs from the perspective of parameter estimation.Approximately 100 stations in a global network are used to generate the UPDs.The results of different satellite systems show that the estimation method,update frequency,and solution mode need to be treated differently.Two regional networks with different receiver types,JAVAD,and Trimble,are also adopted.The results indicate that the receiver-dependent bias has an influence on UPD estimation.Also,the hardware delays can inhibit the satellite-side UPDs if these receiver-specific errors are not fully deployed or even misused.Furthermore,the temporal stability and residual distribution of NL UPDs are significantly enhanced by utilizing a regional network,with the improvements by over 68%and 40%,respectively.It demonstrates that different network scales exhibit the different implication of unmodeled errors,and the unmodeled errors cannot be ignored and must be handled in UPD estimation.
基金This work is partly sponsored by China Postdoctoral Science Foundation(Grant Nos.2021M702507)the National Natural Science Foundation of China(Grant Nos.42204020,42004020,42074032,41931075 and 42030109)the Key Research and Development Plan Project of Hubei Province(Grant Nos.2020BIB006).
文摘The Haiyang-2D altimetry mission of China is one of the first Low Earth Orbit(LEO)satellites that can receive new B1C/B2a signals from the BeiDou-3 Navigation Satellite System(BDS-3)for Precise Orbit Determination(POD).In this work,the achievable accuracy of the single-receiver ambiguity resolution for onboard LEO satellites is studied based on the real measurements of new BDS-3 frequencies.Under normal conditions,six BDS-3 satellites on average are visible.However,the multipath of the B1C/B2a code observations presents some patchy patterns that cause near-field variations with an amplitude of approximately 40 cm and deteriorate the ambiguity-fixed rate.By modeling those errors,for the B2a code,a remarkable reduction of 53%in the Root Mean Square(RMS)is achieved at high elevations,along with an increase of 8%in the ambiguity-fixed rates.Additionally,an analysis of the onboard antenna’s phase center offsets reveals that when compared to the solutions with float ambiguities,the estimated values in the antenna’s Z direction in the solutions with fixed ambiguities are notably smaller.The independent validation of the resulting POD using satellite laser ranging at 16 selected high-performance stations shows that the residuals are reduced by a minimum of 15.4%for ambiguity-fixed solutions with an RMS consistency of approximately 2.2 cm.Furthermore,when compared to the DORIS-derived orbits,a 4.3 cm 3D RMS consistency is achieved for the BDS-3-derived orbits,and the along-track bias is reduced from 2.9 to 0.4 cm using ambiguity fixing.