Low Probability Of Frequency Hopping Radar Code Design And Its Anti-acquisition Performance

Requirements of modern and future warfare with high resolution and strong anti-jamming, anti-seizure, anti-destroy ability of the radar must have a low probability of intercept(LPI). LPI technology is not only one of the ways to improve the survivability and combat capability, but also a effective measures to against electronic jamming and anti-radiation missiles .Therefore, the study to the LPI radar has a important research significance.LPI radar were made as research background in this dissertation, the coding sequence in which FH communication system commonly used were adopted as the hopping pattern of a coded frequency-hopping signal, and this type of radar signal with the confrontation performance were in-depth studied. The main research contents of this dissertation are as follows:First of all, the basic knowledge of LPI radar was introduced, including concept, principle and intercept factorthat measuring the intercepted performance, then according to the intercept factor formula, the effects of various factors LPI performance were also studied. Combining with the reconnaissance technology of modern intercpt receivers, focuseed on a new concept -- low probability of exploitation (LPE), compared it with the LPI of differentiation.Second, studing the designed requirements of the LPE radar wavetype, choose the ideal type of signal. The two coding sequences -- Costas code sequence and RS code sequence in which FH communication systems commonly used were studied, and their sequence properties, such as Hamming correlation properties, equilibrium properties and characteristics of frequency hopping interval were detaily analysed. Lastly, the role of wide intervals hopped on a LPE radar was simply introduced.Finally, two advanced interception processing methods -- dechirping analysis and cyclic spectral density analysis were detaily analysed. Assumed that intercept receiver uses this two intercept method, then analysed the intercept situation of CFH signal by simulating. In order to better explain the against performance of the CFH signal, the intercept processing gains of 6 kinds of LPI signal were simulated, and the LPE performance of each signal were compared by theirs intercept exploiting factors. Simulation results show that the CFH signal is a kind of radar signal, has a good performance to against the interception and has good application prospect in mondern LPI radar sysytem.