Tangential Targets Detection in LFMCW Radars

Tangential targets are those targets travelling perpendicularly to the radial direction of the radar rotating antenna. These targets produce zero Doppler frequency shifts relative to the transmitted frequency. Consequently, these targets are considered as fixed targets to the radar Moving Target Indicator (MTI) and automatically removed. This problem is solved in pulse radar by passing the output of the matched filter into a parallel channel to the MTI channel containing a zero velocity filter (ZVF) and clutter map processor. In this paper, a similar approach is applied in Linear Frequency Modulated Continuous Wave (LFMCW) radars with de-chirping schemes. The output of the first Fast Fourier Transform (FFT) is split into two paths; a traditional one and a ZVF with clutter map processor one. The output of the traditional channel and the ZVF channel are then passed to a hit processor to produce a hit report. The capability of the proposed method in detecting tangential targets as well as slowly moving targets in LFMCW radar compared to traditional scheme is validated through the Receiver Operating Characteristic (ROC).