相关时延估计误差对测频误差的影响

声学多普勒测速技术采用宽带编码信号进行多普勒频移估计时会产生测频误差，该误差来源主要分为两种：（1）宽带信号频谱不对称；（2）相关时延存在估计误差。文章主要讨论相关时延估计误差对测频误差的影响，分析了其产生的原因以及该误差对测频误差的影响。忽略相关函数简化误差以及滤波后频点不对称，推导得到由相关时延估计误差导致的测频误差的解析式。进行了仿真和湖试数据分析，不同频移下的测频误差与理论测频误差一致，不同填充系数下的实际测速误差与理论测频误差变化趋势相同。该对比结果验证了相关时延估计误差会对测频误差产生影响，证明了由相关时延估计误差导致的测频误差的解析式可信。

The influence of correlation delay estimation error on frequency measurement error

There is error in the acoustic Doppler range rate measurement, where the broadband coded signal is used for Doppler shift estimation, and the error source is mainly due to the asymmetry of broadband signal spectrum and the error in estimating correlation time delay. In this paper, the cause of the error in estimating correlation time delay and the influence of the error on the error of frequency measurement are discussed. By ignoring the error in simplifying correlation function and the frequency point asymmetry after filtering, the formula of frequency measurement error caused by the error of correlation delay estimation is derived. Simulation and lake trial results show that the calculated and tested frequency measurement errors under different frequency shifts are consistent, and the variation trends of the actual speed measurement error and the calculated frequency measurement error under different filling coefficients are the same. The comparison results prove that there is an error in estimating correlation delay, which leads to the frequency measurement error.