Accurate and Omnidirectional UWB Radar Imaging Algorithm With RPM Method Extended to Curvilinear Scanning Model

Ultrawideband pulse radars are a promising technology for high-quality imaging sensors for rescue robots in the near field because they have the advantage of high range resolution. We have already proposed the accurate and fast imaging algorithm as range point migration (RPM), which employs the direction of arrival (DOA) with the global characteristic of the multiple observed ranges. However, this algorithm assumes the line scanning of an omnidirectional antenna and limits the imaging range. To overcome this limitation, this letter derives an extended RPM method, which accomplishes omnidirectional imaging and accurate target positioning. As a false-image-reduction scheme in this method, this letter introduces a postprocessing algorithm, which constrains the searching range for DOA estimation by using the initial RPM image. The results of numerical simulations, including noisy situations, show that the proposed method accomplishes accurate and omnidirectional imaging on the order of 1/100 wavelength and enhances the imaging range while avoiding false images.