Direction of arrival estimation in time modulated linear arrays

Direction of arrival (DOA) estimation is a very important technology for smart antennas, which have been widely used in many applications such as radar, communication and sonar etc. Various techniques for DOA estimation have been proposed. The commonly used techniques for DOA estimation are subspace based methods, such as multiple signal classification (MUSIC) and its variations. However, these methods cannot be applied to TMLA directly due to that some channels in TMLA are forced to zero during a special time in a time modulation period. To overcome this difficulty, a method based on beamspace composed of sideband signals and center frequency signal for DOA estimation in TMLA with unidirectional phase center motion (UPCM) is proposed in this paper.