Pseudo-random Code Phase Modulation Research Articles

Research on a Wind Lidar Without Blind Zone Based on the Technologies of Pseudo Random Code Phase Modulation and Heterodyne Detection

In this measurement method, a wind lidar system with no blind zone based on the technologies of heterodyne detection and pseudorandom code phase modulation is proposed. The simulation results show the feasibility of the method. 15m range resolution and 7.75cm/s line of sight (LOS) wind velocity resolution can be achieved from 0 m to 300m, when the laser transmitted power is 2mW, the transmitted pulse length is 100us, the receiving telescope aperture is 2cm, and an accumulation times of 10. The simulation results also show the positive effect of the transmitted pulse length.

Optimization of Orthogonal MSK Waveforms for Active Sonar Using Genetic Algorithm

In order to solve the high peak to average power ratio (PAPR) problem of pseudo random code phase modulation (PRCPM) signals, minimum shift keying (MSK) modulation waveforms with constant envelope were introduced into underwater detection. Genetic algorithm (GA) was proposed to optimize pseudo random binary codes used for MSK waveforms, in order to design sonar waveforms with various performances. After MSK complex envelope signal was obtained by theoretical analysis, the optimizing objective functions for a single waveform and a group of waveforms were presented. The optimized single waveform with low autocorrelation sidelobe values can reduce false alarm number and the difficulty of target decision. When multiple sonar systems work as a team, the optimized group of orthogonal waveforms with low autocorrelation sidelobe values and cross-correlation values can alleviate interferences between each other. In the simulation, the correlation performances of a single waveform and a group of orthogonal waveforms were presented, and ambiguity function showed that the designed waveforms had good velocity and distance resolution, which means that the optimized MSK waveforms are suitable for underwater detection.

基于伪随机码相位调制和相干探测的激光测距技术研究

基于伪随机码相位调制和相干探测的激光测距技术研究

Research on Multi-Fuze Co-Channel Interference Suppression Based on Pseudorandom Code Phase Modulation

This paper introduces the working principle of the pseudorandom code phase modulation pulse, analyzes the theoretical foundation of multi-fuze co-channel interference suppression achieved by phase modulation of the signals through pseudorandom coding, and through the calculation and analysis of simulation, verifies the feasibility of the multi-fuze co-channel interference suppression based on pseudorandom code phase modulation.

Anti-Jamming Performance Simulation of PN-LFM Combined Ranging System

The pseudo-random binary-phase code phase modulation and linear frequency modulation (PN-LFM) combined ranging system is a new detection system, which has proven to be powerful capacity in range resolution, velocity resolution and maximum range measurable without ambiguity. In this paper, we study the anti-jamming performance of the new ranging system, especially in the fractal stochastic noise environments. We analyze the impact mechanism of fractal noise on the PN-LFM detection system, and simulate the output of correlating detection. The cross correlation function, power spectrum function and average power of pseudo random signal and fractal noise are deduced, compared with the impact of white noise on the pseudo code detection system. Simulation shows that PN-LFM combined ranging system possess powerful anti-jamming capacity, and performs better in the fractal noise environment than Pseudo random code phase modulation system.

Performance Analysis Concerning Anti-noise for Pseudo-random Code Phase Modulation and Pulse Amplitude Modulation Combined Fuze Based on Doppler Effect

Performance Analysis Concerning Anti-noise for Pseudo-random Code Phase Modulation and Pulse Amplitude Modulation Combined Fuze Based on Doppler Effect