Doppler enhanced frontal radar images of multiple human activities

Current through-wall radar implementations yield top-view images of human activities. However, radar operators may find frontal images of humans easier to interpret since they resemble human perspectives. High-resolution frontal images are challenging to generate since they require large radar apertures and high carrier frequencies. We propose a methodology to generate high-resolution frontal images of moving humans using a Doppler radar with a limited size aperture operating at a low carrier frequency. The target is imaged using three dimensional Fourier processing along azimuth, elevation and Doppler. The additional Doppler dimension enables us to reduce the resolution requirements along the cross-range dimensions in terms of aperture size and number of elements. Additionally, we analyze the effect of Doppler resolution, the orientation and range of the human subject with respect to the radar for three different human activities - running, skipping and crawling.