Element‐localized Doppler STAP (Space Time Adaptive Processing) for clutter suppression in automotive forward‐looking RADAR

Abstract

SUMMARYIn forward-looking radars such as automotive radars, it is necessary to suppress the reflected undesirable signal (clutter) from such objects as the ground surface (especially hills), guard rails, and buildings, in order to detect moving targets ahead. When using a pulse-Doppler filter (PDF), which is the conventional method for clutter suppression, separation is difficult when the velocity of the target relative to the clutter is small. In this paper, as a high performance clutter suppression method for such low-velocity targets, we propose element-localized Doppler space time adaptive processing (ELD-STAP), which includes a PDF in the preprocessing, and which uses an array antenna. In the proposed ELD-STAP, only the PDF output corresponding to the Doppler frequency breadth of the clutter, predicted from the speed of the vehicle on which it is mounted, is selected for applying STAP, and hence the dimension of the data vector, which is the greatest difficulty in the application of STAP, can be reduced. By reducing the dimension of the data vector, not only the computation load, but also the number of cells that must be referenced to estimate the clutter correlation matrix (called secondary cells), can be reduced. Computer simulation reveals that the proposed ELD-STAP yields an improvement factor better than that provided by the combination of PDF and multibeam forming (MBF).