三星无源定位的精度分析及定位算法

 在三颗地球同步卫星加气压高度表的无源定位中，定义了气压高度表水平几何误差因子(HDOP)和伪距位置几何误差因子(PDOP)，并给出了相应的数学表达式和分布图。提出了在卡尔曼滤波算法中增加多普勒频率作为观测量，同时选用衰减记忆法滤波，并给出了相应的算法。仿真结果表明：衰减记忆法滤波可以有效克服因Singer模型不准确引起的卡尔曼滤波发散；对于高中动态用户，增加多普勒频率后的衰减记忆卡尔曼滤波算法的定位精度要高于常规卡尔曼滤波法和迭代最小二乘法的定位精度。

Precision Analysis and Positioning Algorithm for Triple-star Passive Positioning

In the passive positioning of three geostationary satellites plus barometrical altimeter,the barometrical altimeter's horizontal dilution of precision(HDOP) and the pseudo-range's position dilution of precision(PDOP) are both defined,the formulas and distribution figures of such HDOP and PDOP are also given.In Kalman filtering the Doppler frequency is added as a new measurement and the attenuated memory filtering is employed,also,the corresponding algorithm is given.The simulation results are indicate that the attenuated memory filtering can effectively prevent Kalman filtering from divergence caused by the inaccuracy of Singer model.For high and medium dynamic users,by adding Doppler frequency as a new measurement,a higher positioning precision of Kalman filtering can be achieved,and this precision is also higher than that of Iterative Least Square.