Research on laser ranging technology based on chaotic pulse position modulation

Abstract

Chaotic pulse position modulation (CPPM) modulates chaotic information in the pulse interval. Since the distortion of pulse shape has little effect on information transmission, it has been widely used in communication field for many years, especially in secure communication. In this paper, a laser ranging system based on chaotic pulse position modulation is proposed. The CPPM signal combines both merits of pulse signal and chaotic signal to improve the anti-crosstalk capability of the system. The experimental scheme is given in this paper, and the CPPM signal based on logistic chaos mapping is realized by digital simulation. Since different parameters selection would affect the autocorrelation of signal sequence, DE (differential evolution) algorithm was used to optimize these parameters in order to make the sequence have better correlation characteristics. In view of the good correlation characteristics of the signal, time-domain matched filtering is adopted to obtain the delay. The chaotic pulse position modulation technique proposed in this paper preserves the strong anti-interference ability of random signals, also controls the maximum and minimum values of the interval between pulses, which reduces the performance requirements for the laser. Finally, the feasibility of the scheme is verified by experiments. Since the signal is obtained by oscilloscope sampling, the signal processing part adopts centroid algorithm to improve the measurement accuracy.