Analysis Of URE Characteristics Of Satellitesignal In Space

In recent years,with the rapid development of satellite positioning and navigation technology,Global Navigation Satellite System(GNSS)has been applied more deeply and widely in the field of civil aviation than ever,especially with the initial of regional positioning navigation services of BDS in 2012,researches on monitoring and evaluating navigation performance and methods for evaluating positioning accuracy have became a key research field.This thesis aims at the analysis of a key indicator in the evaluation of satellite navigation performance: User Range Error(URE),the characteristics of GPS and BDS satellites' URE is analyzed,including following contents:1.Data acquisition and pre-processing: Acquire and pre-process the 2017 full-year GPS and BDS precise ephemeris and broadcast ephemeris as data sources for URE calculation,the pre-process includes precise ephemeris' format interpretation,parameter extraction,interpolation,and broadcast ephemeris' format interpretation,parameter extraction,calculation of satellites' position and clock error,antenna offset correction and satellite clock error correction.2.URE calculation and statistical characteristic analysis: Choose appropriate timing system and coordinate system for URE calculation,combined with the pre-processed ephemeris data,URE of 31 GPS satellites and 14 BDS satellites were calculated.Througt the the exploration of the statistical characteristics of GPS and BDS staellites' URE,the asymmetric double S function is used to describe the GPS satellites' probability density,asymmetric double S function and LogNormal function is used to describe the BDS satellites' probability density,which have a better performance than the traditional normal distribution hypothesis.3.URE time domain characteristics analysis and positioning accuracy improvement: Through the time domain characteristic analysis of URE,the hopping modes of GPS's URE are described and the hopping points of GPS and BDS satellites are summerised.According to the URE calculation and analysis result,the positioning weight matrix of GPS and BDS satellites are calculated respectively,which provides a basis for the improvements of the positioning accuracy.