Analysis of BDS ARAIM user receiver nominal bias

Abstract

Beidou navigation satellite system (BDS) has provided open services for the most part of the Asia-Pacific region and plans to provide global service in 2020. In the future, it is necessary for BDS to support ARAIM. As an important parameter of ARAIM, the maximum nominal bias (B nom ) of BDS need to be determined. This paper aims to estimate the impact of nominal biases on ARAIM user performance of BDS. In particular, we focus on the signal deformation and the satellite group delay of BDS signal.To estimate the nominal bias caused by the signal deformation, it is assumed that the code measurements are affected by the correlation loss. The ICAO has described the fault signal distortions of broadcast signal. But it is not appropriate to BDS. We chose a model modified by the comprehensive consideration of the filter provided by Stanford University and 2OS TMB configuration provided by Beijing Satellite Navigation Center.Ideally, the satellite antenna is supposed as a point source for the signals. But the real antenna has biases with the look angle. To estimate the nominal bias caused by the satellite group delay, we assume that BDS signal group delay is similar to GPS IIR-A.In order to guarantee the rationality of B nom , a simulation of maximum nominal bias for GPS+BDS has been operated in this paper.