半无数据调制信号捕获跟踪算法研究

半无数据调制是指在每个节点发送的信号上都调制有同相和正交两路伪码,同相通道上无数据信息,正交通道上调制数据信息,两通道上的伪随机码相互正交。根据半无数据调制的信号样式,采用联合捕获及联合跟踪算法对信号进行基带处理。在捕获阶段,对单通道捕获与相干联合、非相干联合及差分相干联合等捕获算法在捕获概率及捕获时间方面的性能进行对比,在码跟踪、载波跟踪阶段,通过比较单通道跟踪与联合跟踪算法在不同干扰场景下的跟踪误差协方差,选择最佳的捕获及跟踪算法。仿真结果表明,相干联合捕获算法捕获概率最高且平均捕获时间较短,而码环和载波跟踪环的联合跟踪算法具有较高的跟踪精度及可靠性。

Research on Acquisition and Tracking Algorithms for Half Data Modulated Signals

Half data modulation means that the signals sent by each node are modulated with two pseudo codes,which are the in-phase pseudo code and the orthogonal pseudo code.The in-phase channel is void of data information while the orthogonal channel modulates data information.The pseudo random codes in these two channels are mutually orthogonal.According to the signal pattern of half data modulation,this paper proposes the joint acquisition and joint tracking algorithm for baseband processing.In the acquisition phase,this paper compares the performance of acquisition probability and acquisition time between single channel acquisition and other acquisition algorithms such as coherent joint,incoherent joint and differential coherent joint.In the phase of code tracking and carrier tracking,the tracking error covariance of single channel tracking and joint tracking algorithms in different interference scenarios is compared,so as to select the best acquisition and tracking algorithm.Simulation results show that the joint acquisition algorithm has the highest acquisition probability and the shortest average acquisition time.The joint tracking algorithm of code loop and carrier tracking loop has high tracking accuracy and reliability.