Research On Testing Method Of Beidou Navigation Receivers

With the development of China Beidou satellite navigation system(BDS),many new applications are being introduced and terminal performances are attracting people's much more attention.Then GNSS receiver manufacturers increasingly depend on common test procedures to ensure terminal performance requirements.However,the common test document only meets receiver general requirements,not including specific requirements.So,establishing the scientific evaluation for specific requirements has become a key problem in the area of test method.In our paper,establishing the test methods of receiver for city environment and assisted-BDS(A-BDS)receiver is the key study.The research is divided into two parts.1.The paper focusing on the problem that how to improve the navigation terminal performance under city environment because of its wide application and complex signal propagation.Based on received Beidou satellite signal power shadowing under different environments in city application,the paper proposed a statistical Markov model with three states: line-of-sight(LOS)-shadow-block,and using a combination of mixture Gaussian functions to approximate the distribution to describe signal variations to represent environment parameter variations.Channel parameters are evaluated from the experimental data in shanghai and utilized to verify a simulated model.Results presented in the form of signal probability density functions,correlation coefficient of not less than 85% showing close agreement with measurements.This paper proposes a method of calculating characteristic parameters vectors' distance between different environments from statistical model(GM-HMM).The results showed that urban canyons and highway are typical environments,suburban environment does not have the typical distinction.Finally,paper proposed the theoretical positioning accuracy in urban canyons and highway,18.50 and 54.74 m,which can be used as performance reference for common receiver testing.2.With the needs of growing location-based service,a more high-performance satellite positioning technology-assisted global navigation satellite system(A-GNSS)becomes a new hotspot in area of navigation and positioning.Now,3GPP has already provided supports for GPS,Galileo,GLONASS and QZSS,SBAS,so standardization work of introduction BDS into 3GPP organization is very imperative.In this paper,we first analysis the performance of GPS L1 C/A with assistant information,then by taking into account the difference between BDS and GPS,including the unique nature of GEO/NGEO satellites' navigation message data length and format,we design the sensitivity requirements of BDS B1 following A-GPS with-138 dBm in coarse times assistance and-142 dBm for GEO 147 dBm for NGEO in fine time assistance.The results between A-GPS and A-BDS of typical sensitivity test cases are shown in this paper,which show that the suggested sensitivity requirements satisfy the minimum performance requirements under technical specification of 3GPP TS 36.171.