频域相关器在低轨小卫星中的应用

针对频域相关器在频域上进行直接序列扩频信号的捕获,可以显著地加快捕获速度,缩短捕获时间,在进行直接FFT补零做法的性能分析后,指出直接补零会带来性能的恶化。然后提出了一种新的算法,即把频域相关长度加倍,证明它可以完美地解决频域相关器的FFT长度不匹配的问题,同时与时域相关器相比,仍然大大地降低了计算量,缩短了捕获时间,并给出了在基于数字信号处理器(DSP)实现时频域相关器和时域相关器的计算量比较结果。

Application of correlator in frequency domain for the LEO satellite-communication

The acquisition of direct-sequence-spread spectrum signal could be done via correlator in frequency domain, which can speed up the acquisition process and shorten the acquisition time greatly. After the performance analysis of direct zero padding to FFT, which could degrade the performance of acquisition, a method of doubling the length of the correlator in frequency domain, which can solve the problem of FFT size mismatching of correlator in frequency domain perfectly, is presented. The comparison of two correlators, namely in time domain and frequency domain respectively, is made according to the specific computation load based on the DSP.