| There is the distance and velocity coupling problem of the traditional continuous active sonar signal LFMCW,which cannot effectively use the signal bandwidth in the continuous process.The LFM-COSTAS signal is able to use more bandwidth by using circular COSTAS sequence but there is still a problem of velocity ambiguous.In order to seek continuous active sonar signal with better detection performance,this paper proposes a novel coded multi-modulation signal(M-COSTAS)based on M sequence and circular COSTAS sequence.The ambiguous function and anti-reverberation performance of non-recurrent continuous active sonar signal are analyzed.Detailed simulations for target detecting performance are conducted,and some useful results are gotten.The main research results and innovations of this paper are as follows:1)The performance of anti-reverberation non-recurrent continuous active sonar signal is analyzed using Q function.The results show that the M-COSTAS signal which is proposed in this paper is the best anti-reverberation signal when detecting the relative low speed target.2)The parameters of PeCAN sequence and M-COSTAS signal of are studied.The results show that the shorter coded width of each PeCAN sequence is,the higher range resolution of the PeCAN sequence phase coded signal is.The length of M sequence and the hopping space of circular COSTAS sequence have closely influences on the ranging performance of M-COSTAS,the longer length of M sequence,the lower sidelobe in ranging and the higher range resolution;the longer hopping space of circular COSTAS sequence,the higher range resolution3)The detection performances of different non-recurrent continuous active sonar signal are studied.Compared with LFM-COSTAS of the same time-bandwidth,M-COSTAS gets a lower sidelobe in ranging and can solve the problem of velocity ambiguous;compared with M sequence coding signal of the same phase coding width and time width,M-COSTAS get a higher range/velocity resolution. |
PDF Full Text Request