PMF-FFT算法中码多普勒频率影响的分析及补偿

Analysis and Compensation for the Effect of Code Doppler Frequency in PMF-FFT Algorithm

  • 摘要: 针对高动态长时间积累下,码多普勒频率会导致PMF-FFT算法出现码相位走动问题,不利于直扩信号的捕获的问题,推导了码相位走动与积累损失和参数估计偏差的定量关系. 在PMF-FFT算法的基础上,提出利用Keystone变换校正码相位走动,从而补偿码多普勒频率. 仿真结果表明,新算法能有效补偿码多普勒频率,在37 dB/Hz载噪比、10 ms相干积累时间和10-6虚警概率的条件下,单次检测概率达到98%.

     

    Abstract: In high dynamic and long-term integration condition, the code Doppler frequency will lead to code phase migration in PMF-FFT algorithm, which is not conducive to the DSSS signal acquisition. After in-depth study on this issue, the quantitative relationship among the code phase migration, integration losses and parameters estimated bias were derived and simulated. Based on PMF-FFT algorithm, a compensation method for code Doppler frequency was proposed, which used Keystone transform to correct code phase migration, so as to compensate the code Doppler frequency. Simulation results show that, on the condition of 37 dB/Hz CNR, 10 ms coherent integration interval and a fixed false alarm possibility of 10-6, the new algorithm can effectively eliminate the code Doppler frequency and has a single detection possibility of 98%.

     

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