Performance Assessment Of BeiDou Signal-in-Space Accuracy

The assessment of the satellite system performance is not only one of the main basis for defining the scope of application of the system,checking the health of the system and upgrading system,but an important guarantee for the satellite system continuous operation.As the most basic and the most important index in the performance,the performance evaluation of the accuracy is one of the most important tasks in evaluating the service performance of the satellite system.It can not only provide technical support for the application of satellite system,but also has some reference value for other engineering application and scientific research.In this paper,two methods are proposed to evaluate the accuracy of BeiDou Navigation Satellite System signal-in-space,one is "BOTTOM-UP",the other is "UP-DOWN".The former uses ephemeris data and the latter uses pseudo-range observations.The main content of this paper is to use these two methods to evaluate the performance of BDS signal-in-space accuracy:1.According to the definition of signal-in-space User Range Error and the Root Mean Square URE calculation method given in the GPS-SPS-PS,the BDS Instantaneous URE and rmsURE formulas are deduced considering the elevation constrains.Using the satellite orbit error and satellite clock error calculated by broadcast ephemeris and precise ephemeris,the accuracy of BDS evaluated with the "BOTTOM-UP" method,the analysis shows that BDS URE is better than 3.8 m(95% confidence),User Range Rate Error is better than 2.0 mm/s(95% confidence),User Range Acceleration Error is better than 0.025 mm/s2(95%confidence).2.Based on the "BOTTOM-UP" method,the software platform of BDS signal-in-space accuracy performance evaluation based on MATLAB is developed.The software integrates each evaluation index into a modularized process to facilitate the subsequent experimental research.3.In accordance with the "UP-DOWN" method,based on the received pseudo-range observations from NovAtel Flex Pak6 receiver,the BDS URE is evaluated after the ionosphereerror,troposphere error,multipath and receiver noise error is corrected.The analysis shows that BDS URE is better than 2.0 m(95% confidence).In this paper,the "BOTTOM-UP" and "UP-DOWN" are compared and analyzed,the results show that the two methods match well.