Research On Identifying Techniques To Pulse-Doppler Radar System

The Pulse-Doppler radar is a new type of radar system. Its signal is very complex and the platform of PD radar has a high threat. Early identification techniques based on classical parameters such as: radio frequency, pulse width, pulse repetition interval (PRI). It cannot satisfy the demand of both real-time and high precision in EW application.The thesis start from operation principle of PD radar and its signal features, for instance, coherence, intrapulse modulation character, staggering of PRI. Parameter extract methods are discussed. The autocorrelation detection is analyzed for coherence, simulation results are provided. Using time frequency analysis and image processing the modulation of linear frequency-modulated (LFM) signal is analyzed and using relatively non-ambiguity phase revaluation technique, the modulation identification of phase-coded signal is also studied.Parameters' confidence factors are fused with D-S evidence theory for ascertaining the confidence factor belonging to PD radar in fuzzy condition. In order to avoid detecting wrongly different modes of single PD radar to different emitters, the hypothesis matching structure in Seaview system was used to identify many modes of PD radar. It can detect effectively different working modes of PD radar to single radar.As radar signal environment being more complex and emitter parameters being more incredible, existed emitter identification systems are ambiguous partly. Therefore, the concept of specific emitter identification (SEI) is discussed, which can identify specific emitters or platforms. A new method is brought forward for SEI by using rising and falling edge to cluster dynamically and deinterleave pulse chains. Finally, a SEI system based on precise PRI analysis is introduced.