RTCA协议下北斗完好性降效参数算法设计及检验

The algorithm and validation of BeiDou system(BDS) integrity degradation parameters with RTCA protocol

目前我国北斗导航增强系统的完好性参数设计缺少针对差分信息有效性的降效参数设计,不满足航空无线电委员会(RTCA)提出的接口协议,无法同国际其他GNSS星基增强系统相兼容。根据RTCA接口协议,针对我国卫星导航系统的完好性降效参数处理算法进行了研究,利用北斗实测数据分析了完好性降效参数对用户增强服务的影响,验证了算法的有效性。结果表明,正常情况下,北斗导航系统增强服务三维定位精度可达到1.13m。当用户丢失部分差分改正信息时,定位精度约1.44m,精度下降约27.4%,利用完好性降效参数对过期差分信息进行降效处理,优化定位权阵,可将定位精度提高至1.17m,达到正常增强服务水平。

Currently, the design of integrity parameters for the satellite based augmentation system of BDS is lack of degradation parameters for the differential information＇s availability, and can＇t satisfy the RTCA protocol. So the satellite based augmentation system of BDS is not compatible to the other international satellite based augmentation system of GNSS. The integrity degradation parameters of BDS were designed according to the RTCA protocol, and the effect on the user positioning was analyzed by using the BDS measured data. Based on these, the effectiveness of this algorithm was demonstrated. The results show that, the location precision of the augmentation system for BDS reaches 1.13m. However, if the user failed to receive some differential correction, the positioning precision reaches 1.44 m, decreases by 27.4% approximately. In this situation, by optimizing position matrix with the integrity parameters to the past differential message, the positioning precision will increase to 1.17m, so the authorized service will recover.