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DS/FH(直接序列扩频/跳频扩频)混合扩频信号的快速捕获问题亟待研究。电离层色散效应增加了BPSK(二相相移键控)调制的DS/FH信号捕获的复杂度,并导致不同频点信号载波相位难以保持连续。通过估计电波传播路径上TEC(电子浓度),可以消除电离层色散效应的影响,利于应答机精确测速。提出一种划分子带的信号捕获方法,放宽TEC搜索步进,缩短搜索TEC的时间,从而实现信号的快速捕获。分析了划分子带个数与捕获时间及捕获能量损失的关系,在实现过程中可通过调整子带的个数来控制捕获能量损失,使得捕获模块设计更加灵活。
DS / FH (Direct Sequence Spread Spectrum / Frequency Hopping Spread Spectrum) hybrid spread spectrum signal fast acquisition problem to be studied. The ionospheric dispersion effect increases the complexity of DS / FH signal acquisition modulated by BPSK (Binary Phase Shift Keying), and makes it difficult to maintain the carrier phase of signals at different frequencies. By estimating the TEC (electron density) on the propagation path of the radio wave, the influence of the ionospheric dispersion effect can be eliminated and the accurate speed measurement of the transponder can be facilitated. A sub-band signal acquisition method is proposed to relax the TEC search step and shorten the search time of TEC, so as to realize the fast signal acquisition. The relationship between the number of subbands and the acquisition time and energy loss is analyzed. During the implementation process, the number of subbands can be adjusted to control the energy loss and make the design of the capture module more flexible.