CMMB定位接收机频率捕获方法

Frequency acquisition method for CMMB positioning receiver

CMMB(中国移动多媒体广播)电视广播信号采用的是正交频分复用(OFDM)调制技术,利用其进行导航定位需要首先解决频率捕获的问题。在CMMB信号帧头中存在两个完全相同的同步序列,利用其在时域上的相关性进行频偏估计,并在加性高斯白噪声和多径信道下进行了仿真。仿真结果表明,该方法达到了捕获测距信号所需精度,可以作为CMMB定位接收机频率捕获方法。

It is necessary to deal with the issue of the acquisition of the carrier frequency in the navigation/positioning via the signal of the CMMB(China Mobile Multimedia Broadcasting), in which the orthogonal frequency division multiplexing(OFDM) modulation technique is adopted. Since there are two identical sequences on the beginning of each frame, the correlation of them was used to estimate the frequency offset. The algorithms were simulated for the AWGN and multipath channel, and the results show that this method can achieve the required accuracy for capturing the ranging signal, and can be applied to the positioning receiver.