Research On Key Technologies Of Cooperative ECM In Multi-syndrome Jammers For Countering Radar Net

With the rapid development of digital signal process and netted technology, the radar net has been proved to be an important technique for countering ECM, stealth airplane, low altitude attack, and anti-radiation missile. Compared with the independent radar, the detectability and accuracy of the radar net has improved greatly, because netted radar is a system with the outstanding characteristic of the muti-structure, omnibearing, and high precision. With regard to ECM aspect, the netted radars have strengthened the data exchange during each other, exploited the advantages of cooperative ECCM to the full, so that the ECM of the single jammer is valid.In order to improve the ability of ECM for countering radar net, several jammers have been allied together, unified allocation of resources for cooperative interference. The formation composed of all attendant jammers is a typical method to implement cooperative interference. This method utilizes many small jammers which are distributed in front of the attack flight to organize into formation for interfering the radar net cooperatively. It is obviously better to resist single radar by more jammers when sufficiency jamming resources can be obtained.This dissertation studies on the key technologies of cooperative interference for countering the radar net. The main contents are summarized as follows:1. The basic principle and modulation types of suppression jamming and deception jamming are first introduced. In order to improve the stability of the suppress effect of concentrated false targets for LFM pulsed radar with mean level(ML) CFAR detector, ordered and concentrated false targets are designed to reduce the detection probability of the radar. Simulation results show that false targets can reduce the detection probability of radar to limit value. After that three cooperative suppress jamming methods united random noise; smart noise; and suppress false targets, implemented by multi-jammers, are proposed to enhance the suppress effect. Meanwhile a three-dimensional cooperative deception jamming carried out by three coherent jammers against to the radar is proposed. Then the jamming effect of cooperative interference is discussed thoroughly. The theoretical and emulational effects of the cooperative patterns are analysed thoroughly.2. Based on the organization method and the pivotal signal procedures of radar net, detection probability, GDOP, and tracking precision are proposed as the indexs for evaluating the performance of single radar and netted radar. Then according to the descend degree of radar performance in electronic counter measure environment, the evaluation function of jamming effect is established. Then four effective factors such as time, space, frequency, and processing are drawn into calculating the assessed value of single jammer against to single radar. For the scene of cooperative penetration formation counter against radar net, “weighted integral of the assessed value” is brought forward as the evaluation function of jamming effectiveness, on the basis of taking the route information of the flight formation into consideration.3. With regard to the ECM environment of syndrome jammer formation infer against radar net, jamming resource allocation model has been established according to the detection probability, GDOP, and tracking precision of multi-radar fusion center,which includes the submodel of allocating interference object and the submodel of selecting the jamming signal. After taking full advantage of flight parameters, “weighted integral of decreasing threat generated by radar net for flight formation in different penetrating process” has been brought forward as target function. Then the optimum JRA model for optimize jamming effect is also established. Based on the dual-string encodings, genetic algorithm(GA), standard particle swarm optimization(PSO), and quantum-behaved PSO(QPSO) are proposed for optimizing JRA. Lastly, the algorithms are compared with each other in terms of the solution quality, robustness, convergence rate,and reliability by a general Monte Carlo simulation.4. Route planning is researched for minimizing the detection performance of radar net for unmanned air vehicle(UAV) formation which has ECCM capability as they ingress to a selected target through a netted radar threat environment. This research demonstrates how to plan optimum flight-path route that makes maximum utilization of UAV blanket jamming capability and flight terrain-masking opportunities to significantly reduce radar detection. With Digital Terrain Elevation Data, the solid terrain can be represented as the group of quadratic mesh grids points with known coordinates in a three-dimensional(3-D) rough terrain environment. Then the survivability look-up tables composed by the detection probability of the radar net describe the probabilities that the UAV formation is in certain state at each grid point, e.g., safe, detected, tracked, or hit. The survivability model is also used to calculate an expected cost for the arbitrary mission route. Thus the route planning in a large geographical area is formulated as a typical large-scale optimization problem with the particularly aerodynamic constrains, such as maximum turning angle, maximum diving/climbing angle, minimum route leg length, and minimum flight height. An evolutionary algorithm based framework, a hybrid particle swarm optimization and self-adjustable genetic algorithm(HPSOSAGA) and sparse A* search(SAS) algorithm are then proposed to design an offline/online path planner for UAV formation autonomous navigation respectively. The proposed planners have been tested under homogeneous and ECM environments respectively and the series of experimental results show that the proposed algorithms can find safe-optimal curved routes quickly and efficiently in raising the surviving probability of the assault formation under complicated environments.