基于光学测角与信号时差的同步卫星无源测轨

精确测量和确定同步卫星轨道是实现高精度导航、定位等应用的基础,光学测角定轨和卫星通信信号测时差定轨是两种最重要的无源测轨方法,各有优缺点。本文提出将光学测角与无线电通信信号测时差相结合,可实现对卫星的单次测量定位,多次测量提高定轨精度。推导得到卫星到光学站的距离表达式,实现对卫星位置的解析求解。通过GDOP方法,分析了光学站与无线电站的不同布站方式对定位精度的影响,据此提出了优化布站方式。通过计算机Monte-Carlo仿真,比较分析了联合测轨方法与单一光学测轨方法的测轨精度。仿真结果表明:若无系统误差时,24小时观测数据统计定轨位置误差为25m,预报1周位置误差为200m,约为单一光学方法的2/3;当存在系统误差时,需采用自校准方法估计系统误差,基于24小时观测数据的单一光学方法未能实现自校准定轨,而联合测轨方法定轨精度可达到约6m,归一化系统误差估计精度优于0.1,预报1周的位置误差约为140m。

Passive Orbit Measurement of Geosynchronous Satellite Joint Angles from Optical Measurement and Time Difference of Arrival from Signals PENG

Precision orbit measurement and determination of geosynchronous satellite is the foundation for satellite navigation, positioning, and so on. Both methods based on optical measurement and based on Time Difference of Arrival (TDOA) with satellite’s communication signal have advantages and disadvantages. A new orbit measurement method is proposed joint the optical measurement and TDOA measurement, which can solve satellites position with only one time measurement of angles from one optical station and one TDOA from two radio stations, and improve the orbit precision. The analytic expression of range from satellite to optical station is derived, thus the position can be solved, too. By GDOP analysis method, the position precision is analyzed with different stations’ layout, and a layout suggestion is proposed. The orbit precision’ improvement from joint measurement is improved by Monte-Carlo statistical orbit determination, which has been compared with purely optical measurement. The simulation result shows that, if there is system error, after orbit determination with 24h’s measurement data, the position error is about 25 m from orbit determination and 200 mfrom 7days prediction, which is only 2/3 to purely optical measurement. If there is system error, the self-calibration method is used for orbit determination, and the position error is 6 m from orbit determination and 140 m from 7days prediction, the estimated system error is 0.1 after normalization, while purely optical method has failed with self-calibration method.