Abstract:

Aimming at the problems of poor antijamming performance and easily being influenced by Doppler effect of the underwater acoustic (UWA) communication system, the UWA communication system scheme based on the fractional Fourier transformpulse position modulation(FRFT-PPM) and the Doppler compensation method in fractional domain are proposed. The FRFT-PPM system employs the linear frequency modulation (LFM) signal as carrier signals and translates information modulated by peak position in fractional domain based on PPM principle, which has the advantages of an adjustable communication rate (the maximum rate is up to 1.6 kbit/s) and a good anti-noise disturbance performance. According to large Doppler tolerance of LFM signals and the scale transmission property of FRFT, the peak position compensation in fractional domain is presented to suppress Doppler effect caused by the relative motion of platform. The feasibility and robustness of this system are verified by a large number of computer simulation and lake experiments.