Research On Spread Spectrum Signal Sensing Methods Under Non-cooperative Conditions

With the rapid development of science and technology,communication technology has been widely used in various fields around the world,especially in the field of military communications.Electronic information warfare has become one of the indispensable forms of warfare for modern warfare.Spread spectrum communication is widely used in the field of military communications because of its anti-interference ability and strong anti-interception ability.In the military electronic communication confrontation,due to the complicated environment,low signal-to-noise ratio and lack of prior data,it brings difficulties to the detection and identification of spread spectrum signals,and it is an important hot spot of current research.This paper mainly studies the detection of spread spectrum signals,the identification of direct sequence spread spectrum signals and frequency hopping signals,the estimation of direct sequence spread spectrum signal parameters,and the estimation of frequency hopping signal parameters.Firstly,based on the introduction of spectrum sensing theory,the detection algorithm suitable for non-cooperative signals is selected,and the energy detection algorithm is used to simulate under different false alarm probability and different signal to noise ratio.Secondly,the algorithm of feature detection of spread spectrum signal based on time-frequency analysis is introduced.The time-frequency map is optimized by image processing.Then,the direct sequence spread spectrum signal and frequency hopping signal are characterized,and the image-based processing is proposed.Time-frequency analysis of the overall recognition algorithm for spread spectrum signals.Finally,the algorithm of modulation mode recognition based on feature parameters is introduced,and the classification tree is reorganized and the simulation verification of 8 different modulation signals is completed.The parameters of the time-frequency diagram extraction are used to estimate the parameters such as the hopping period,the take-off time,the frequency hopping frequency and the symbol rate of the frequency hopping signal,and the simulation is completed.Aiming at the direct spread spectrum and frequency hopping detection and parameter estimation methods studied in this paper,a sensing strategy is established and simulation verification is completed,The simulation results show that the perceptual strategy system can complete the detection and parameter estimation of DSSS signals and frequency hopping signals at lower SNR.