风云四号地球静止轨道卫星测距系统误差标校及其定轨影响分析

Analysis of the ranging systematic error of the FY-4 geostationary satellite and its influence on orbit determination

测距系统误差是影响地球静止轨道(GEO)卫星定轨精度的主要误差因素,GEO卫星的静地特性使得测距数据系统误差特别是测站系统差和卫星轨道存在较强相关性,必须通过其他独立手段解决。首先利用仿真数据分析了地面系统误差和星上系统误差对轨道的影响特性,随后以风云四号B星(FY-4B)测距系统为例分析了测距实测数据,分析结果表明风云四号B星测距系统中存在异常的系统误差,为确定该系统误差的来源,设计了一系列试验方案进行分析,通过试验排除地面设备系统误差,确定了风云四号B星测距系统误差来自于研制厂家提供的错误星上转发器时延值,利用定轨估计解算星上系统误差对其进行标校,以及利用标校后的观测数据重新定轨,各站残差由15 m降至2 m,定轨精度由800 m提高到20 m,分析表明,通过定轨估计解算对星上系统误差进行标校的方法是切实有效的。

The ranging systematic error is the main factor that affects the orbit determination accuracy of geostationary earth orbit(GEO)satellites.The geostationary characteristics of GEO satellites make the ranging data systematic error.Especially for the station systematic error,it has a strong correlation with the satellite orbit.Therefore,the independent means must be used to solve.The simulation data are firstly used to analyze the impact characteristics of ground systematic error and on-board systematic error on the orbit.The FY-4 B satellite ranging system is taken as an example to analyze the measured range data.The analysis results show that there is an abnormal systematic error in the FY-4 B ranging system.To determine the source of this system error,a series of schemes are designed.Through experiments,the systematic error is not from the ground or the satellite.And it is determined that the systematic error of the FY-4 B comes from the satellite.The orbit determination estimation is utilized to calculate the on-board systematic error to calibrate it.The calibrated observation data are used to achieve orbit determination,and the residual error of each station is reduced from 15 m to 2 m.The orbit determination accuracy is improved from 800 m to 20 m.The analysis results show that the method of calibrating the systematic error on the satellite through the orbit determination estimation is practical and effective.