航天扩频测控系统中伪码捕获方法研究

 针对航天扩频测控系统的捕获需求,提出一种能够降低谱峰衰减且具有较高频率估计精度的FFT伪码捕获方法.在部分匹配滤波过程中采用汉宁窗对数据加权后再累加,以减小谱峰衰减.采用插值FFT估计多普勒频率,以提高频率估计精度,根据不同测控环境下伪码捕获的特点,分析比较了抛物线插值法和改进的Rife法两种插值算法.理论分析和仿真结果表明,改进方法能够减小FFT输出的峰值衰减,提高多普勒频率估计精度.

Research on Pseudo Code Acquisition Method in Aerospace Spread Spectrum TT&C System

In order to meet the acquisition requirement of aerospace spread spectrum TT&;C system,a FFT-based code acquisition method was proposed which could reduce the spectrum peak degradation and get high frequency estimation accuracy.It integrated the data weighted by hanning window in the partial matched filter to reduce the spectrum peak degradation.Interpolated FFT was adopted to estimate the Doppler frequency in order to enhance the frequency estimation accuracy.According to the acquisition characteristics in different TT&;C conditions,two interpolation methods such as parabolic interpolation and improved Rife were analyzed.Both analysis and simulation demonstrate that the proposed method can reduce the spectrum peak degradation and improve the Doppler frequency estimation accuracy.