时变多普勒频移直扩信号的检测方法

针对时变多普勒频移影响直接序列扩频信号相关性,导致常规检测方法失效的问题,分析了时变多普勒频移对相关峰值的影响,仿真了多普勒频移变化率与相关峰值间的关系。利用短时间内多普勒频移变化很小的特点,设计了利用后一时段载波将前一时段信号下变频,从而克服多普勒频移对相关峰值影响的方案,并利用高阶累积量提取信号周期特征完成了信号检测。仿真了新方法在时变多普勒频移情况下不同信噪比时的检测概率。理论分析和仿真表明该方法计算量小、检测概率高、适应范围广。

Modified Detect Method of DSSS Signal with Time-varying Doppler Frequency Shift

The time-varying Doppler frequency shift reduces the correlative peak value of DSSS signal, because the conventionalmethods can not detect the signal. In order to solve this problem, the influence of time-varying Doppler frequency shift on correlativepeak value is analyzed.The relationship of Doppler frequency shift and correlative peak value is quantitatively simulated.A new methodis proposed, which utilizes high order statistics to extract periodical characteristics and detect DSSS signal and can eliminate theinfluence of doppler frequency shift.The relation between detect probability and Doppler frequency change rate under various SNR issimulated.The theoretical analysis and computer simulation results show that new method has lower computational complexity, higherdetect probability, wider range of application.