利用部分相关法扩展多普勒容限的方法

由于发射机和接收机的相对运动,在扩频通信系统中会产生多普勒频移,影响伪码和载波的捕获。传统的叉—点积法进行频率估计时,其鉴频范围仅为数据速率的1/4,多普勒容限较小。当多普勒频移超过数据率的1/4时,传统方法估计的频率将发生符号反转,从而输出错误的频率估计。为了提高叉—点积法的鉴频范围,提出了一种利用部分相关法提高多普勒容限的方法,即将相关累加时间变为数据周期的一半,从而将数据解调支路多普勒容限扩大1倍。

Method of Doppler tolerance extension using partial correlation method

Due to the relative motion of the transmitter and the receiver,the spread spectrum communication system will produce Doppler frequency shift,effecting the acquisition PN code and carrier.When we use the traditional cross product auto frequency tracking （CPAFC） to estimation frequency,its discriminate range is 1/4 data rate and Doppler tolerance is small.If the Doppler shift exceeds 1/4 data rate,the estimated frequency sign with the traditional method is inversed,which outputs an error frequency estimation.In order to expand the discriminate range of the traditional CPAFC,the partial correlation method is proposed to improve the Doppler tolerance,namely halved the time of coherent integration and double the the Doppler tolerance of data demodulation branch.