一种基于最大熵法的高分辨率GPS多路径信号延迟估计方法

A Max-entropy-based High-resolution Time Delay Estimation Method for Multi-path Signals of GPS

在对相关延迟估计方法分析的基础上,给出了一种基于最大熵法的高分辨率延迟估计方法,用来对GPS多路径信号延迟进行高分辨估计。首先利用互功率谱计算法把时域的延迟变换到频域的频移,然后把求得的功率谱等效为一个时间序列,再对该时间序列求最大熵功率谱。最大熵功率谱是一种最大限度地保留截断后丢失的＂窗口＂以外信号信息的估计方法,它使估计谱的熵最大,具有高频率分辨率,从而可以实现对延迟时间的高分辨率估计。仿真结果说明：该方法可对2倍采样周期的延迟进行正确估计,比相关延迟估计方法有较大提高。

The correlation time delay estimation method is a basic method. But its resolution is limited by the code frequency. Based on the analysis of this method, a new high-resolution time delay estimation method is presented. It utilizes the high-resolution for frequency of max-entropy power spectrum estimation method. Firstly it changes the time delay to frequency shift by co-correlation power spectrum, then the power spectrum is equalized to a new time sequence. Finally max-entropy power spectrum is utilized to get high-resolution time delay estimation. The max-entropy power spectrum is based on the max-entropy theory, and has high frequency resolution. Simulation result is provided to verify the method＇s validity. It can give the correct estimation of time delay of double sample period. It is superior to the correlation time delay estimation method in resolution.