A Research On Target Aircraft Detection Methods Based On Forward Scattering Wave Of Beidou Navigation Satellite

Modern warfare has evolved from the battle of physical weapons to the competition of high-tech forces.In high-tech warfare,radar plays an increasingly important role.Nowadays,most of the commonly used radars are active monostatic radars.Active radar is easily detected by the enemy because of its high power when transmitting signals and monostatic radar has limited capability of detecting stealth aircraft,bringing great challenges in the application of radar.In order to improve the accuracy of radar target detection and strengthen the safety of radar itself,it is of great significance to put the focus on bistatic radar of passive radar in the study of radar transmitter.The thesis is based on the detection method of forward scattering wave vehicle of Beidou navigation satellite.This method uses signal of Beidou navigation satellite as signal source of radar transmitter and applies bis tatic radar system which receives and transmitts radar signals on specialized machines respectively.The application of using of artificial satellites as radiation sources that people knows is only from a small number of reports on the use of GPS satellite signals as radiation sources.From the experiment,it could be seen many advantages of bistatic radar which uses artificial satellite as radiation source.The advantages of bistatic radar include flexible erection position,large effective detection range,strong survivability and high reliability of document of target profile and so on.Based on the detection method of forward scattering wave vehicle of Beidou navigation satellite,the thesis mainly studies three aspects,namely the study on traditional bistatic radar system,on space-earth bistatic radar system based on satellite radiation source and on recognition and classification of target aircraft based on machine learning.The thesis first introduces the background,significance and current situation at home and abroad of the research.Then it introduces the working principle of traditional bistatic radar,the form of target holographic signal and the modified form of holographic signal after reduction and simplification,the relation between target doppler frequency image and target profile and the correspondence relation between improved holographic signal and the difference in phase and height in target profile.The above research is conducive for radar to realize the detection,recognition and trac king of target when the target aircraft passes through the baseline of bistatic radar.Then,the thesis studies the advantages of applying broadcast signal of four global satellite navigation systems as radiation source of bistatic radar and it establishes the model of Beidou satellite signal and the judgment method of testing signal source as radar emitter.Then,the thesis establishes the scheme of bistatic radar system based on radiation source of Beidou navigation satellite and simulates the implementation of this system.Finally,the thesis extracts the feature of the holographic signal elements of the target aircraft and classifies the target aircraft by using the method of machine learning.