DORIS实时定轨中的频偏估计方法研究

Estimate of Frequency Bias Method in DORIS Real-time Orbit Determination

针对DORIS测站和卫星USO频率偏差引起的测量数据不准确的问题,提出了一种频偏估计方法,消除了测量数据中的最大误差项。在摄动加速度模型仅考虑40×40阶重力场、固体潮和日月三体引力的条件下,利用该方法处理了SPOT-5卫星10d的测量数据。结果表明,实时轨道的径向精度优于30cm,与SPOT-5卫星的实时轨道精度相当;3D精度优于80cm,达到了SPOT-5卫星的设计精度。

DIODE is a real-time on-board orbit determination software, embedded in the DORIS receiver since 1998. Frequency biases between beacons and satellites USO are the max errors in DORIS measurement data. The purpose of this paper is to find a method to es- timate the frequency biases. To start with, we describe the state and measurement equations about DORIS real-time orbit determination. Then, we present a method to estimate the fre- quency biases. Using our method and considering the 40 x40 Earth gravitational fields, solid tide, moon and sun attractions, we analyze ten days~ measurements data of SPOT-5. The results show that the radial component RMS is better than 30 cm, which correspond to the SPOT-5 real time orbit accuracy, and the 3D RMS is better than 80 cm, which achieves the specifications of SPOT-5.