| With the rapid development of aerospace technology,the safety of spacecraft in orbit is highly valued by military countries.Radio frequency stealth technology can effectively reduce the interception probability of the spacecraft active radiation source,and enhance the strategic advantage in future space attack and defense,which has important research significance.RF stealth technology aims to improve the signal anti-detection,anti-sorting and anti-identification capabilities.With the sensitivity improvement of reconnaissance receivers,it is difficult to achieve signal antidetection based on signal power control.Anti-sorting and anti-recognition have gradually become important technical directions for anti-interception.Starting from the strategy of maximum signal uncertainty and focusing on the cluster sorting function of reconnaissance receivers,this paper proposes a design method of radio frequency stealth communication signals based on a fourdimensional hyperchaotic system and implements algorithms on the FPGA platform.The main research work and innovative achievements of this pater are as follows:(1)Aiming at the insufficient complexity and short-period phenomenon of traditional chaotic systems,this paper proposes a construction method of four-dimensional hyperchaotic systems based on perturbations.This method introduces feedback control and disturbance measures in the Lorenz chaotic system,and ensures that the system is in a hyperchaotic state by optimizing the control parameters.This paper proposes a fast period search algorithm,which realizes the fast period search of four-dimensional hyperchaotic systems.This paper proposes a fast period search algorithm,which realizes the fast period search of four-dimensional hyperchaotic systems.The experimental results show that the complexity of the four-dimensional hyperchaotic system is significantly stronger than that of traditional chaotic systems,and it effectively solves the short-period problem caused by the limited accuracy of the computing platform.(2)Aiming at the frequency-domain scanning model of reconnaissance equipment,this paper proposes a method for designing wide-interval frequency hopping patterns based on particle swarm optimization.In this method,a four-dimensional hyperchaotic system is used to generate hyperchaotic frequency hopping patterns through real-valued quantization and hash mapping.Aiming at minimizing the probability of signal frequency domain alignment,a particle swarm algorithm is introduced to optimize the frequency interval.The experimental results show that the hyperchaotic wide-interval frequency-hopping pattern has good complexity and eliminates the short-period phenomenon,and is significantly superior to traditional design methods in terms of wide-interval characteristics and generation efficiency.(3)Aiming at the cluster sorting function of reconnaissance receivers,this paper presents a design method of radio frequency stealth communication signals based on the joint hopping of frequency hopping frequency and frequency hopping period of hyperchaotic system.The experimental results show that the RF stealth communication signal design method proposed in this paper effectively improves the signal anti-sorting and anti-interception capabilities.(4)The algorithm design of the RF stealth communication signal based on the four-dimensional hyperchaotic system is realized on the FPGA platform,and the feasibility of the RF stealth algorithm is verified. |
