Acquisition of Binary Offset Carrier Modulation Signals in a Highly Dynamic Environment

‍ ‍Aiming at the problem of low acquisition accuracy and large computation of the modulation signal of BOC （Binary Offset Carrier） with first-order Doppler rate， In this paper， a Partially Matched Filter combined with Fractional Fourier Transform （PMF-FRFT） algorithm is proposed， which used Fractional power spectrum accumulation combined with Fractional FRFT. In this algorithm， PMF was used to segment the signal， and the fast correlation between the received signal and the local pseudo-code was realized. Then combined with the energy aggregation characteristics of Linear Frequency modulation signal （LFM） in different FRFT domains， the fractional FRFT combined with fractional power spectrum accumulation was used to accurately determine the optimal order. Finally， FRFT was combined with fractional power spectrum accumulation in the corresponding optimal order to accurately capture the signal with the first order Doppler rate of change. Simulation results show that the algorithm can reduce the amount of computation and shorten the acquisition time. Moreover， when the power spectrum is accumulated 20 times， the accurate capture can still be achieved when the pseudo-random code length is 1023 and the SNR is about -22 dB.