弱信号环境下北斗导航接收机位同步算法研究

Research on Bit Synchronization Algorithm for BD Navigation Receiver in Weak Signal Environment

为了满足在弱信号环境下的使用并提高接收机跟踪灵敏度,在接收机中采用锁频环进行载波跟踪是非常有必要的。由于锁频环并不对相位进行跟踪,造成相关器的能量不集中在同相支路,而是同相/正交支路均包含有信号能量,致使传统接收机的同步算法无法使用。为了解决弱信号环境下的同步问题,提出了2种新同步算法,进行了理论推导和算法描述,在实际接收机中完成了实现,并给出了测试结果。结果表明,2种新同步算法在弱信号环境下均能实现比特同步和帧同步,是一种行之有效的同步算法。

In order to improve the tracking sensitivity of receiver and satisfy the use requirement in weak signal environment, it is necessary to make use of frequency-locked loop to perform the carrier tracking.As the frequency-locked loop doesn＇t track the phase of carrier,the coherent integration power is integrated in both I and Q path instead of only I,so that the bit synchronization technique of traditional receiver is unavailable. In order to solve the problem of synchronization in weak signal environment, this paper proposes theory description of two new methods to achieve bit synchronization and realize in real receiver at last.The test results show that the two new synchronization methods can achieve bit synchronization and frame synchronization in weak signal environment, and they are available.