Quality Control Methodology For BDS Precise Point Positioning In Polar Regions

In recent years,our country gradually takes understanding and participating in the polar polar affairs as an important national strategy.In Polar Regions,high precision location information is required when conducting small area construction,monitoring and drilling.However,China is still lack of a romote navigation methodology and cannot provide effective position service for the polar expedition,transportation and military activities.With no need to establish overseas stations,the precise point positioning(PPP)technology with Beidou Navigation Satellite System(BDS)can alleviate the navigation and positioning needs in the Polar Regions to a certain extent.However,it is still limited by the number of visible satellites and data quality affected by the special geographical environment in Polar Regions.China will launch upgraded satellites and expand its regional Beidou Navigation Satellite System(BDS)to global coverage,which is expected to provide real-time,stable,and high-precision time-space benchmarks in the Polar Regions.And there is a lack of clear understanding of the quality control and positioning performance estimation of BDS precise point positioning.This paper aims to apply the theory and method of precise point positioning quality control and evaluation to,according to the characteristics of the polar BDS precise point positioning,improve the positioning solution,such as improving the data pretreatment effect and the understanding of the characteristics,optimizing the polar GNSS positioning error detection and correction method and refining precision Stochastic model.Finally,BDS PPP Service Performance is evaluated.The main research work and contributions are as follows:1.The theory and methods of precise point positioning technology and the quality control is summarized firstly.Then,the quality control methodology of polar BDS PPP is proposed.Foucsing on the quality control of data preprocessing,the correction of the main error source,the estimation of the observation variance and the positioning performance evaluation,the technical discussion and experimental demonstration are carried out.2.The statistical properties of the polar BDS pseudorange error is analyzed,also the detection sequence of GF combined cycle slip detection method.The method and standard of the cycle slip judgment are improved by using the ionosphere delay variation rate.Experiments show that the error detection method based on pseudo range combination works well in polar area.Also,GF combined cycle slip detection method with ionospheric delay change factor is helpful to improve the accuracy of the polar BDS cycle slip detection,convergence speed and reliability of polar BDS precise point positioning.3.Comparative analysis of the periodicity of the BDS multipath time series and multipath changing discipline with the elevation is conducted.The correction methods and effects of multipath errors for polar GEO and non-GEO satellites are discussed.4.A refinement method of BDS observational random model based on pseudorange random noise characteristics is proposed.Combined the pseudo random noise estimated with a moving window and the observation posterior variance of three kinds of BDS satellites,the variance matrix of BDS observations is obtained.The method can reasonably estimate the stochastic characteristics of the observations,the positioning accuracy and convergence were improved to a certain extent.The prior information is more reasonable and realistic,which can reflect the contribution of accuracy difference of observations to precise point positioning.5.The performance of BDS PPP in Polar Regions is evaluated.The data quality evaluation threshold was given through experiments.Moreover,the convergence accuracy and positioning accuracy of polar BDS PPP were summarized after processing and analyzing the BDS observations of all polar IGS station.6.The difference of BDS PPP performance in different Polar Regions is discussed under current observation conditions.The usability evaluation of polar BDS PPP service is proposed and its result is briefly discussed based on the measured data.Combined with the simulation results of BDS coverage in Polar Regions,the performance of BDS PPP service in Antarctic and Arctic is evaluated.