Research On The Technology Of Single Airborn Station Passive Location

On the modern high tech battlefield, the ability of concealable reconnaissance and attack of electronic countermeasure warfare equipments will improve their battlefield viability efficiently. The possibility to locate radar emitters avoiding transmission is crucial in a variety of military applications, in particular when a flying platform(aircraft or helicopter) is entering in an unknown(and potentially hostile) area. Thus passive location techniques which use the passive mode have always been considered an important topic in the field of electronic reconnaissance and have always received great attention by countries all over the world. Due to its flexibility, covert operation and broad applicability to locate scene, single airborne station passive location technique has become an important development direction of passive location. Therefore, this thesis will focus on the research of airborne single station for fixed or varying ground target passive location problem. The main contents are as following.Firstly, the present studies on single station passive location are reviewed. Several current classical kinds of single-station passive location systems are introduced. At the same time, comparative analysis between several typical single station passive location methods is made.Secondly, the related technology principles of single station passive location are introduced. First of all, with the help of several typical location methods the technology principles of single station passive location are analyzed. Then, the influences of station flight attitude and trajectory on single station passive location are summarized.Thirdly, a location method for phase difference rate of change with single airborne station in narrowband scene is studied, its observability and key influencing factors of location accuracy are analyzed. The methods of key parameters extraction are given. Based on WVD algorithm the method for phase difference rate of change is improved. The analysis on the principle of the extraction of the instantaneous phase information and phase difference rate of change using time-frequency ridges is made. Based on time-frequency interferometer, a location method for phase difference rate of change with single airborne station is studied.Fourthly, traditional single station passive location methods inevitably involve a number of parameters estimation problems. For different signal types and platform attitude changes, multimodal positioning parameter extraction steps should be applied. However, the parameters extraction accuracy directly determine the final performance of the positioning methods. To overcome the above deficiencies, a direct single airborne station passive location method based on subspace data fusion is studied. Across the step of parameters estimation in time or frequency domain of the traditional methods, the position of multical far field narrowband radiation sources is completed directly by solving the builted objective function which mainly been constructed by observational data in distance form.Fifthly, the application of the above mentioned method is extended to broadband scene. In the fractional fourier transform dorm the energy of the LFM signal can be focused well. Without the adverse effects of the cross terms, target resolution and parameter detection can been completed perfectly. The characters can be used to apply the mentioned subspace algorithm to solve the direct location of LFM radiation sources. Some simulation are performed.