Accuracy Analysis Of Polar Multimode GNSS Precision Point Positioning

Polar regions,located at the north and south poles of the earth,are not only rich in mineral resources and biological resources,but also have a great impact on global climate and environmental changes due to their special geographical location.The emergence of a variety of satellite positioning and navigation systems has opened a new situation for GNSS technology breakthrough,and multi-GNSS fusion positioning has become a research hotspot in the field of GNSS in recent years.The establishment of the Multi-GNSS Experiment(MGEX)has laid a foundation for the research and development of multi-system fusion precise point positioning,and created experimental conditions for the in-depth exploration of multi-mode PPP.In view of the fact that there are few applications of precision point positioning technology in the polar environment,and more is given priority to with single GPS navigation technology,based on the data of MGEX observatory,this paper analyzes the performance of multi-mode GNSS precise point positioning in polar environment,and the main research and conclusions are as follows:(1)This paper mainly analyzes four data quality evaluation indexes of navigation and positioning satellite system:multipath,signal-to-noise ratio(SNR),data utilization ratio and cycle slip.In terms of multi-path,the change of multi-path in one day and the influence of multi-path on the altitude Angle are analyzed.In terms of signal-to-noise ratio,the change of the SNR in one day and the influence of the SNR on the change of altitude Angle were analyzed.In terms of cycle slip by the ratio of the observed value to the cycle slip is evaluated,and the data utilize rate is evaluated by the ratio of the actual received epoch to the effective epoch.(2)Through the analysis of the calculation results of 11 different system combinations of precise point positioning,it is found that the positioning results of the combination of BDS navigation satellite system and Galileo navigation satellite system in polar environment are poor.Compared with the dual-system combination,the three-system combination significantly improves the positioning performance.The convergence time in the three directions of east,north and zenith is shortened by 10.3%,14.1%and 7.3%,respectively,and the positioning accuracy is improved by 9.2%,4.6%and 11.7%,respectively.The convergence time and positioning accuracy in the north direction are obviously better than those in the east direction and zenith direction.(3)Comparing the results of multi-mode PPP in winter and summer in polar environment,it is found that the convergence time and positioning accuracy of multi-mode PPP in summer and winter in polar environment are less different,and the positioning effect of four-system combination is better than that of two-system combination and three-system combination.The PPP positioning results of different system combinations in the polar region and the middle and low latitudes are compared.It is found that the multi-system combination PPP positioning results in polar environment have a large difference in the convergence time and a small difference in the positioning accuracy compared with those in the middle and low latitudes.Compared with the polar region,the positioning effect of the two-system combination in the middle and low latitudes is better than that of the three-system combination and the four-system combination.