Signal Sorting Methods For Unknown Radar Emitters In Complex Environments

Radar emitter signal sorting is one of the key procedure of signal processing in modern high-technology war and future-generation information war. It is a key technology to perception in network center warfare. It's the chief technology to the passive radar guidedmissile with target homing in electronic countermeasures. And it's also the difficulty technology of signal processing in current electronic intelligence system (ELINT) and electronic warfare support measures (ESM). With the development of low-probability of intercept (LPI), intrapulse wave transform and multi-parameter agility technology and so on, various work systems and anti-interference instruments in extreme complex radar signal environments presented a serious challenge to radar signal sorting.Aiming at the key issue to solve urgently in signal processing of electronic warfare, system model and algorithms for signal sorting of unknown radar emitter in complex environments are studied systematically and exploringly in this dissertation. Theoretical fruits are as follows.1 A new model structure for signal sorting of unknown advanced radar emitter is proposed which broke through the traditional sequential sorting mode based on five parameters (BOA, RF, PRI, PW, TOA). And consequently a fire-new thinking is introduced to solve the difficult problem of unknown radar emitter signal sorting in complex environments. This paper presented an idea of multiparameters combination signal sorting and a conception of feature extracting for signal sorting. And the recognition and estimate processing are to be invoted in the signal sorting system, which increased the sorting step based on pulse amplitude modulation information. The algorithms for implementing the proposed model structure and testing experiments validate that the new model structure is more effective than the current model structure.2 The tolerance problem of radar signal sorting is to be analyzed. The traditional radar signal sorting method is seted on the base of tolerance so that partition of optimal boundary has been a difficulty to current radar signal sorting region. From different views, different multiple-parameters clustering sorting methods are used. Several methods including sorting method based on delaminating coupling and SVC, sorting method based on cascade coupling and SVC, and sorting method based on SVC&K-Means clustering, which resolved tolerance problem of radar signal sorting.3 The type-entropy and density-entropy are to be presented, which discribs quantitily complex degree and dense degree of emitter pulses signal environment. And recognition technology of type-entropy and density-entropy is introduced into signal sorting system, which estimate availability of the clustering sorting result, so that a novel radar sequence signal sorting system is to be presented.4 Aiming at change characteristic of radar emitter instantaneous pulse parameters, using fractal geometry theory and Hilbert-Huang transform theory, a new feature extraction method for radar pulse sequences is presented based on structure function and empirical mode decomposition. It can extract efficiently the periodical changefeature - G feature that hides in the complex pulses environment and find out a new feature for the signal sorting of interleaved radar pulse-sequences. The experimental result shows that the feature extracting method is effective.5 A surf-algorithm of signal sorting is presented, using amplitude modulation information of radar pulses. This dissertation summarizes the model and processing flow of the surf-algorithm, with the test result.