Research On Broadband DBF Technique For Electronic Reconnaissance

Electronic reconnaissance, which is the premise of Electronic Warfare (EW) tactics, is an important means of access to military intelligence. With the rapid development of radar technology, the increasingly density of radar signal and the increasingly complexity of signal form present radar EW a sever challenge. Therefore, the introduction of digital technology into radar reconnaissance receiver is an inevitable trend of EW.In this thesis, broadband DBF (digital beam forming) technique,a digital direction -finding technique, is applied to radar reconnaissance direction-finding system. Parameters'measurement of intercepted radar signals can be achieved by the application of broadband DBF and digital channelization technique. Firstly, the basic principle and algorithms of digital channelization are discussed, as well as the principle of the digital channelization based on STFT (Short-time Fourier Transform) is deeply studied. Then it is verified by the computer simulation that the STFT method has the capability to measure the time and frequency domain parameters of simultaneously arrived signals with accuracy. And then, a more efficient algorithm called multiphase FFT algorithm is presented, which can better satisfy the EW reconnaissance receiver's requirements of real-time processing over instantaneous broadband signals and high-precision measurement. Secondly, the methods that commonly used to measure the signal's angle of arrival (AOA) in radar reconnaissance receivers and the principle of DBF direction-finding technology are discussed. Thirdly, the thesis key research has analyzed the principle of broadband DBF direction-finding based on spatial domain FFT and its implement methods. The simulation results in different antenna arrays are given, which shows that the method has the ability of distinguish the AOA of simultaneously arrived signals.