On Chaotic Synchronization Control Methods Of A Class Of Secure Communication Systems

Chaos is a kind of special complicated nonlinear systems, which is ubiquitous in nature. And it has been intensively applied in various fields such as biology, physics, chemistry, engineering and information. Because of its certain features such as high randomicity and hyper sensitivity to initial conditions, the application of chaos can be especially found in secure communications, signal progressing and image progressing etc. Since1990s, chaos synchronization has rapidly developed as the key technique in secure communications also be developed, and there are lots of remarkable results in this field. This paper based on the method of state feedback, to design the synchronization controller for the chaotic system. And based on the secure communication simulation, proposed a method which can be applied to the satellite communications.The main contributions are listed as follows:Firstly, for unified chaotic systems, a synchronization controller by using active control method is designed to synchronize two different structure chaotic systems based on Lyapunov stability theory. And the lag synchronization controller is designed for the chaos system with signal transmission delays, which is with simple structure and good control effect. Furthermore, based on chaotic masking scheme, the communication system with two synchronized systems of different structures is set up. And the simulation results show that, the useful signal can be recovered from the receiver effectively.Secondly, the synchronization control problem of chaotic systems with different state delays is investigated. The feedback controller is designed to synchronize the master system and slave system with state delays. Considering the influence of parameter uncertainty and disturbance, the stability theorems are given and the parameters of the controller are solved based on the LMI method. Then, this synchronization control method is applied to the chaos secure communication system.Then, for the chaos system with propagation delays, parameter uncertainty and disturbance, a synchronization controller is designed based on the LMI technique. A stability theorem is given to synchronize the two chaos systems. Based on the synchronization platform, the communication signals can be masked completely by the chaos signal.Finally, the conclusion is given and some open problems are also discussed.