Design of underwater orthogonal waveforms set based on Lorenz chaos frequency modulation

A method based on Lorenz chaos frequency modulation is proposed to design orthogonal waveform sets for the joint detection of the network underwater vehicles where the interferences may exist between echo signals. First, the CFM (chaos frequency modulation) signal model based on Lorenz sequence is established, and its correlation properties and orthogonal performance are analyzed, including the effects of the number and the length of waveforms on the orthogonal performance. The optimization method of the CFM orthogonal waveforms by adding window function to the chaotic sequence is proposed. And then, the echo signal model based on the network group of underwater vehicle that transmits linear frequency modulation signal and CFM signal is structured, and the processing results of the echo signals by using matched filter are compared and analyzed. The simulation results indicate that the method is simple, flexible and efficient, producing a set of orthogonal waveforms with good performances, which has obvious advantage in underwater information detection.