A Fast Acquisition Scheme for Coherent DDS/FFH System

Abstract

For a coherent DDS/FFH system (deeply direct sequence and coherent fast frequency hopping hybrid spread spectrum system), signal has a very large spread spectrum ratio. Signal acquisition process becomes very complex and difficult due to interference and doppler frequency shift in a strong interfering and high dynamical environment. FFT corelation sequence points are very large if traditional frequency-based FFT acquisition scheme is used, FFH requires FFT operation should be completed in a much shorter time (within one hopping duration time), which makes system realization become very complex or even impossible. A partial matched filter combining FFT, coherent accumulation combining incoherent accumulation acquisition scheme is investigated, system realization complexity is reduced.