【摘要】 提出一种改进的全比特算法。新算法将去载波后的信号进行块累加,将20ms的相干积分缩短至1ms,并采用FFT并行捕获,在不影响捕获灵敏度的前提下,大大降低了算法的运算量。利用归一化后最大相关值和次大相关值之差对捕获结果进行判决,提高了判决方法的适用性。最后,利用Matlab仿真的信号对算法进行验证,结果表明:利用20ms的相干积分和5次非相干累加,能够捕获信噪比为-38dB的微弱信号,执行时间缩短了近2/3.更多还原

【Abstract】 An improved full-bit algorithm is proposed.The new algorithm uses block addition upon the carrier-removed signal and shortens the 20 ms coherent integration to 1ms.After that,the signal is captured in a parallel way-FFT.The improved algorithm reduces the computing amount greatly with acquisition sensitivity unreduced.Acquisition results are judged by the difference between the normalized maximum value and second maximum value of autocorrelation.This method improves the applicability of acquisition judgment.At last,the improved algorithm is verified with simulated GPS signal in Matlab.Simulation results indicate that weak GPS signals with SNR of-38 dB can be captured through 20 ms coherent integration and 5times of non-coherent integration,and the executing time is reduced by about 2/3compared with the former algorithm.更多还原