基于多速率内插和最小二乘法的精确同步方法

Precise synchronization approach based on multi-rate interpolation and least squares method

最小二乘法可以利用PN序列相关曲线的对称性实现对接收端接收到的PN序列的相位精确测量。然而实际应用中无线信道带宽有限,接收端还原出来的PN序列只能在极性上和原来的方波形式保持一致,这样导致了相关曲线的变形,因而限制了最小二乘法的实际测量精度。为了进一步改善最小二乘法的测量精度,引入了多速率处理的方法,在不提高前端AD采样频率的基础上,通过增加鉴相曲线零点附近的鉴相点个数,使所用于拟合直线的点更靠近零点,从而提高系统测量精度。仿真结果表明,经过两倍内插后的方法相比内插前在测量性能上有三倍左右的提高。因此经过多速率处理改进后的方法可以显著提高系统对PN相位的测量性能。

The least squares method utilizing the symmetry of the correlation curve of the PN sequence can achieve accurate measurement of the PN sequence phase.However,in practical applications,the wireless channel bandwidth is limited,so that the restored PN sequence is only consistent with the original wave in the polarity which can led to the deformation of the correlation curve and limiting the actual measurement accuracy of the least squares method.To further improve the measurement accuracy of the least squares method,this paper introduced a multi-rate processing method without increasing the front-end AD sampling frequency by increasing the number of phase detector points near zero,that made the points which were used to fit the straight closer to the zero.The simulation result shows that measuring performance of the twice interpolation method gains about three times improvement compared with the approach without interpolation.So with multi-rate processing,the measurement method of PN phase can significantly improve the performance.