Research On Aircraft RF Stealth Performance Evaluation Indexes And Simulation System Implementation

With the development of passive detection technology, the aircraft stealth is no longer confined to the radar stealth, infrared stealth and so on. The passive detection system is characterized by farworking distance, no radio frequency(RF) radiation and good concealment, which make it more and more practical to study the RF stealth technology. How to realize the RF stealth is the key and difficult point in the study of world military powers. Thus, for the evalution of aircraft RF stealth performance and its software implementation, the main research contents and results are as follows:(1)The RF target characteristic parameters and RF stealth performance evaluation parameters of aircraft are presented in detail. For the features of RF target characteristics parameters, the characterization methods of RF target characteristics parameters, such as RF radiation intensity, the uncertainty of inter-pulse and intra-pulse, are specified. The conditional information entropy is employed to measure the uncertainty of inter-pulse. In comparison with the RF uncertain entropy, conditional entropy can evaluate the inter-pulse uncertainty caused by pulse parameters(such as carriers frequency, pulse width, pulse repetition frequency and so on) agility more comprehensively. For the characteristics of RF stealth performance parameters, intercept distance, intercept factor, circular equivalent vulnerable radius(CEVR), spherical equivalent vulnerability radius(SEVR) and probability of intercept are analyzed. What's more, the influence factors of the intercept probability are analyzed from the frequency domain, time domain, the energy domain and the spatial domain. The research lays the foundation for the realization of the RF stealth performance evaluation software system.(2)The characterization methods of RF stealth performance under complex conditions are studied. In the view of the problem of interference and noise in the electronic counter, the influence of the external jamming and noise on the intercept distance and interception factor is analyzed. Simulation shows that how to improve RF stealth performance effectively by interfering with passive detection system. The beam coverage area is studied respectively as an important factor affecting intercept probability under the air-to-ground scenario/air-to-sea scenario. The joint intercept probability is given as the characterization method of intercept probability under air-to-air scenario. The simulation results show that the intercept probability inreases with the increasion of the radiation source's grazing angle or the main lobe width.(3)The evaluation software system of aircraft RF stealth performance is designed and implemented. Firstly, the overall design of the software system and the design of the sub-modules are completed. Newton iterative method and the normalized method are given as the software realization method for the computation complexity of intercept distance and SEVR, which can reduce the calculation time under the premise of meeting the accuracy of calculation and improve the real-time performance of the software system. What's more, many system tests including input and out put tests, integrated display tests and other function tests are carried out. The test results show that the simulation system is reliable and simulation results are correct. The simulation system has good expansibility, which can meet the needs of the semi-physical simulation research in future.(4)Identification capacity is given as the characterization parameter of anti-separation and anti-identification performance of airborne radar. A basic model of identification capacity based on passive detection system is established. Then the effects of signal to noise ratio(SNR) and the dimension of the target's feature on identification capacity are studied. Moreover, the identification capacities of two cases, with and without pulse omission, are respectively analyzed. And the effectiveness of identification capacity of the airborne radar is verified by comparing with the correct recognition probability under the minimum error probability criteria. The research shows that the greater the identification capacity of airborne radar, the worse the anti-identification performance of radar. Based on identification capacity, the design method of frequency hopping signal parameters is put forward. The correctness and validity of the method are verified by numerical analysis.