Study On Passive Radar Imaging Methods Using WiMAX Signals

Passive radar doesn’t transmit signal itself, but relies on illumination sources of opportunity torealize target detection or imaging. The modern communication provides more available illuminatorsof opportunity for passive radar, such as Global System for Mobile communication (GSM) signals,Global Positioning System (GPS) signals, Wireless Fidelity (WiFi) signals, etc. WorldwideInteroperability for Microwave Access (WiMAX) is a new broadband wireless access technology ofmetropolitan area network (MAN) based on IEEE802.16standard. As a possible illuminator ofpassive radar, it can provide higher range resolution and larger detection range as compared toexisting illuminators of opportunity.In this paper, the feasibility of WiMAX signal as a passive radar illuminator is analysed, and thepassive radar imaging methods using WiMAX signal are researched. Cotemporaneously, simulationsare performed to demonstrate the effectiveness of the imaging methods.Chapter1is the preface. The researching background is introduced, including the developmentof passive radar technology, the brief introduction of WiMAX technology, the overseas and domesticresearch status, and so on. At last, the purpose and significance of research are put forward, and thenthe main contents of this paper are summarized.In chapter2, the monostatic and bistatic ambiguity function of WiMAX signal is analyzed basedon the ambiguity function theory, and the range and velocity resolution properties which WiMAXsignal can provide are researched theoretically. Waveform analysis demonstrates the feasibility ofWiMAX signal as the illuminator of passive radar.Chapter3presents a passive synthetic aperture radar (SAR) imaging formation method based onrange-Doppler algorithm using WiMAX signal as illumination source of opportunity. Firstly amatched filter for WiMAX signal is derived to get the one-dimensional range profile, and then thetwo-dimensional WiMAX-SAR imaging is achieved with small rotation angle.Chapter4discusses another passive SAR imaging method based on Filtered Back-Projection(FBP) algorithm. Applying FBP to the returned signals received in different aperture locations, thescene reflectivity is reconstructed, with which the two-dimensional WiMAX-SAR imaging is formedfinally. This method is free from the restriction of radar aperture and is applicable to arbitrary flighttrajectories of receiver.In chapter5, WiMAX signal is used in passive radar system using distributed apertures, and the moving targets imaging is realized. This imaging method is based on Generalized Likelihood RatioTest (GLRT) theory. Then the spatial-and velocity-resolved test-statistic is determined based onsignal to noise ratio (SNR) maximization criteria. Finally, the images of target with correct positionand velocity are obtained. On the other hand, the influence of the clutter on imaging performance isanalyzed.Chapter6is the conclusion of this paper, which summarizes the research results and lists thefuture work to be researched and solved.