THREE-DIMENSIONAL MICROMOTION SIGNATURE EXTRACTION OF ROTATING TARGETS IN OFDM-LFM MIMO RADAR

In monostatic radars systems, only the micromotion signatures projected onto the radar line-of-sight (LOS) can be observed from echoes. As a result, the obtained micromotion signatures (e.g., the radius length of rotation) are sensitive to the radar LOS. In this paper, we propose a method for the accurate estimation of three-dimensional (3-D) micromotion signature with the orthogonal frequency division multiplexing - linear frequency modulation (OFDM-LFM) multi-input multi-output (MIMO) radar technique, which makes use of the advantages of the multi-view of MIMO radar systems and the broad bandwidth of the OFDM-LFM signals. In the proposed method, the Hough transform and Orthogonal Matching Pursuit (OMP) algorithm are introduced to extract the m-D curve features from echoes, and then the 3-D micromotion signatures of the rotating targets are obtained by solving nonlinear multivariable equation systems. The extracted 3-D micromotion signatures are no longer sensitive to the radar LOS, and can provide realistic feature information for target recognition. Simulations are given to validate the effectiveness of the proposed method.