Broadband Signal And Frequency-hopping Signal Direction Finding Technology

The characteristics of the modern electronic war are the wide frequency band, varying types and the unknown form of the signals, which are restricted to improve the intercepting efficiency of the signals. A series of studies on the broadband signals and the frequency hopping signals with the low probability interception will be carried out in this thesis. An effective algorithm method based on a large number of simulation experiments and theoretical analyses will be proposed in the following chapter.The thesis will combine the characteristics of the low probability interception signals with the specific projects to conduct the research, and the organization of this thesis is as follows:1. The introduction to the features of the processing methods of the array signals and the low probability interception signals, several traditional methods of the array signal process, especially the MUSIC algorithm and ESPRIT algorithm.2. The introduction to the effects of the broadband signal on the array signal processing, the TCT will be taken as an example to illustrate the transitional processing method. It is proposed that the virtual aperture method could transfer the traditional narrow band width to the airspace of the virtual aperture expansion requiring no matrix transformation and less array elements, which is verified by a large number of the simulation and experiments3. The research on the characteristics and the networking method of the frequency-hopping spread spectrum communication will be conducted in the thesis. Moreover, the frequency-hopping signal processing, especially, characteristics and the impact of the final frequency-hopping signals for array signal processing will be further studied to propose the time-domain segmentation method, which uses time window to divide the data. Based on two-dimensional array L-finding array structure, the new method without the azimuth and the joint estimation can compare the estimated results with the pre-estimation results. Thus, we can remove the inter-band data results. The application of the arithmetic mean can improve the algorithm performance. Finally, the simulation results show that the proposed method can accurately estimate the frequency hopping signal and the properties of the direction of arrival, and roughly estimate the transition time.