RF Stealth Based Airborne Radar System Simulation And HRRP Target Recognition Research

With the continuous advancement of passive detection systems, the threat to the survival of the aircraft in the battlefield environment is becoming more and more serious. Aircraft radio frequency stealth technology is the stealth technology of the electronic equipment for the passive detection system. So study on RF stealth of airplane has very important theoretical and practical significance. This thesis studies the software simulation of the radar system in the RF stealth software evaluation system. Then the thesis further studies the airborne radar target recognition based on RF stealth technology, including the waveform design of wideband radar and the radar target recognition based on HRRP. The thesis generally consists of four sections, which are detailed in the following:1. For RF stealth radar, this thesis firstly introduces the related theory of RF stealth performance characterization parameters, such as intercept distance, intercept factor, probability of interception, the power of channel intercept and the stationary time. And then analysis the factors that can affect these parameters, including the peak power of radar transmitter, the radar receiver sensitivity and the dwell time of the antenna.2. The RF stealth software evaluation system can simulate the battlefield environment and calculate the RF stealth performance parameters real-time. The radar subsystem is an important part of the system, mainly simulates the function of airborne radar. By analyzing the function of the RF stealth system, the functional requirements and the data interface of the subsystem are obtained, and the software simulation process is given. The simulation system is partitioned into three modules, including transmitter, receiver and antenna module. The function of each module is described. Finally, the modeling and simulation of the whole radar system is completed. Applying it in the RF stealth software evaluation system to simulate the function of the RF stealth performance parameters calculation, and the results of the system is given.3. For wideband radar RF stealth technology and HRRP target recognition, this thesis studies a method of transmitting waveform matching the target impulse response. When the radar transmitter the matching waveform, the waveform changes with the change of target attitude angle, which inevitably leads to the improvement complexity of radar transmitter and has a lower feasibility. In order to reduce the complexity of the radar transmitter, the method of principal component analysis is used to classify the target impulse response. One just need to design a waveform for each cluster, ensure that the radar transmit waveform can be kept unchanged at a time when the target attitude angle is not changed suddenly. The simulation results show that it can improve the radar RF stealth performance and reduce the complexity of the radar transmitter.4. For wideband radar RF stealth technology, this thesis studies the target identification based on target high resolution range profile in the low SNR. The relative distance and magnitude of scattering centers are used as target feature vectors. Applying of machine learning methods to classify, including support vector machine, neural network and deep learning network, the identification performance of the various methods are simulated. The thesis considering the target-aspect sensitivity of HRRPs, applying the fixed angular-sector segmentation way when the identification model is constructed. So the identification model can be selected more accurately when identification by using the target angle information. The simulation results show that the method has high recognition rate in low SNR, which is beneficial to improve the RF stealth performance of aircraft, enable the radar to do the target recognition efficiently under the power control condition.