研究无源北斗定位技术的目的，在于解决目前北斗定位体制下，存在用户数量受限、用 户机需发射信号、定位数据更新率慢等缺点。利用现有的2颗北斗地球同步卫星、1颗备份卫星的 星历信息以及测量获得的时差信息，可以推导出实现无源定位的数学模型。该方法通过试验数据 获得了50 m范围的定位结果，从而验证了该项技术的正确性-The purpose of the passive Beidou, is to solve the current Beidou system, there is the number of users limited user machine needs to transmit signals, slow update rate of positioning data shortcomings. Use of the existing two Beidou geostationary satellites and a backup satellite ephemeris information and measuring the time difference information can be deduced from the mathematical model of the passive location. The test data to obtain the positioning results of the 50 m range, which verifies the correctness of the technology