Research On Direction Finding Technique Of Wide-band Array Signals

Array signal processing is an important method for spatial signal processing. It has been used widely in the field of radar, sonar and communication. By sampling and processing both in temporal and spatial domain, the interested information contained in signal can be exploited fully and interference can be suppressed more effectively.Wideband signal has the merits of more information and less correlation, which are good for targets detecting, parameters estimation, so it has been widely used in detecting systems.In this dissertation, the model and theory of array signal processing are studied firstly, and then, some classical algorithms such as FFT, beamforming, MUSIC and ESPRIT are introduced. The differences among them are discussed later.ISM method and CSM method, which are two classic super-resolution methods for wideband DOA estimation, are introduced. This paper concentrates on CSM, and introduces two representative methods of it, RSS and TCT. We can get the preliminary estimation of DOA by FFT, and then get the super-resolution DOA estimation by focusing transformation. The effectiveness of this method was proved by computer simulation.The super-resolution methods have big computational burden, so it's difficult to apply it to simultaneous systems. In order to overcome this disadvantage, wideband multi-beam amplitude comparison method is introduced. For wideband signal, because of its wide frequency band, which can introduce the difference of beam width, we can't apply amplitude compassion method directly. By using channelized receiver, the frequency band of received signal becomes narrower. So the estimation error will become less.In the last, the array calibration problem was discussed. A modified method of array calibration with gain and phase errors was introduced. It doesn't need the DOA information, which makes it more feasible in practice.