基于误差修正的卫星在轨质心高精度预估与验证

High-precision estimation and verification for the centroid of satellite based on error correction

在星载精密定轨中,通常需要对观测数据进行接收天线质心偏移修正,将测量数据参考点修正到卫星质心,不同方向的质心偏移误差对定轨结果影响差异显著。由于大型平面可展开天线和太阳电池阵的重量和尺寸较大,同时由于地面测试设备、测试方法、环境因素等原因导致地面状态下难以直接测得在大型平面可展开天线和太阳电池阵均展开下的卫星质心,此外,星上其他展开部件等均能在不同程度上影响卫星的质心,这些因素都直接增大了准确预估卫星在轨质心的难度。针对卫星质心误差对分布式SAR卫星基线测量精度的影响,本文从提高卫星质心预估精度的角度,在现有质心测量技术的基础上,提出了一种卫星质心在轨预估技术。利用足够多的实际可测的零部件质量和质心信息,将质心计算与实测数据相结合,基于误差修正理论,实现了以二阶精度计算卫星质心的方法,在工程上有较广的适用范围。采用该方法对某卫星在轨质心误差进行了分析,并经在轨试验标校后,取得了预期的效果,证明了该方法合理可行。

The centroid deviation of the receiving antenna is usually necessary to be modified during satellite precise orbit determination, and to correct the measurement data of the reference point to the centroid of the satellite. The deviation of the centroid in different directions has significant influence on orbit determination. Due to the large flat deployable antenna and the weight of the solar cell array as well as the ground test equipment, test methods, and the environmental factors, the centroid of the satellite under the state of on-orbit is difficult to be directly measured on the ground. At the same time, the centroid of satellite can be affected by other deployable components of satellite. All these factors directly increase the difficulties for predicting the centroid of the satellite. Aiming at the influence of the satellite centroid error on the baseline measuring accuracy of distributed SAR satellite, a satellite centroid prediction technology based on the existing centroid measurement technology to improve the estimation accuracy of satellite centroid is proposed in this paper. Based on the theory of error correction, the method of calculating the centroid of a satellite with second-order precision is realized by combining the calculation of the centroid with the measured data based on enough mass and centroid information of measurable parts. The errors of the centroid a on-orbit satellite are analyzed by this method, and the results show that the method achieves the expected results after the on-orbit test calibration.