基于相关函数包络峰细化的高精度超声测距法

建立了超声测距时延估计模型,由于窄带超声回波参考信号与接收信号的相关函数在极值点附近具有慢衰减高频振荡特性,所以有必要将搜索直接相关函数的极值点转化为搜索相关函数包络的极值点.针对相关峰常规插值方法在多倍插值的情况下存在计算复杂、时延估计精度不高等缺点,结合超声回波信号的窄带带通特性和相关峰细化(Fine Interpolation of Correlation Peak)原理,提出了直接提取相关函数包络及包络峰细化方法,并分析了其计算复杂度.仿真与实验研究表明,该方法能大大提高相关函数包络峰值分辨率,适用于类超声回波信号的带通信号精细时延估计问题.

Method of High Precision Ultrasonic Distance Measurement Based on Fine Interpolation of Correlation Envelope Peak

Firstly,the time-delay estimation model in ultrasonic distance measurement is established.It is necessary to search the correlation envelope peak instead of the direct correlation because the correlation of narrow-band ultrasonic echo reference signal and the receiving signal is oscillatory with similar amplitudes and high frequency around the peak.Because the common correlation peak interpolation method has some deficiencies when it is used for multiple interpolations,the method of extracting directly the correlation envelope and fine interpolation of envelope peak is presented combining with the band-pass specialty of ultrasonic echo and FICP(Fine Interpolation of Correlation Peak) principle.It is proved by experiment and simulation that the method can improve greatly the resolution of correlation envelope peak and can be appropriate for the fine TDE(Time Delay Estimation) of band-pass signal like ultrasonic echo.