深空测控高精度频率估计技术研究

Research on Frequency Estimation Technique in Deep Space TT&C

深空测控信号具有信噪比低、频率变化率大等特点,采用传统的锁相环闭环方式进行高精度频率测量存在低信噪比与高动态之间的矛盾。提出一种基于相位模型的开环频率估计方案,综合利用二维FFT分析、卡尔曼滤波及最小二乘拟合算法,通过事后处理实现深空测控信号的高精度频率测量。仿真结果表明,在考虑噪声和动态条件下,频率估计精度可达0.01Hz。在此基础上通过对实测数据的处理验证了该方案的可行性,为后续的工程实现提供了一种可借鉴的技术方法。

The deep space TT&C signal has the properties of low SNR and high dynamic.A conflict between the low SNR and high dynamic exists for the traditional phase-locked method.This paper puts forward an open-loop frequency estimation method based on the phase model.It combines the two-dimensional FFT analysis,Kalman filter and least square fit to accomplish the high-accuracy frequency estimation after task.The method is validated by simulations.The estimation accuracy is about 0.01Hz when the effects of random noise and frequency changes are taken into consideration.The proposed algorithm is verified through the processing of measured data and provides a technical approach for the future project.