A GMTI method via comparing two consecutive phase difference maps of the same target area for small UAVs

In this paper, we present a Ground moving target indication (GMTI) method based on the analysis of the two phase difference maps (PDM) of the same target scene obtained by one antenna phase center on a slow moving platform. For small unmanned aerial vehicles (UAVs) only one antenna is available to detect moving targets. Using a single antenna and the two PDMs method, odd numbered spatial samples are used to construct the first synthetic aperture radar (SAR) image, and the even numbered spatial samples are used to construct the second SAR image of the same target scene. The along track neighboring pixels phase difference is calculated for each image; and, thus two PDMs are generated. The phase difference values of the corresponding pixels in the two PDMs are almost the same if there are only static objects in the target scene; while if there is a moving target with a reasonable speed in one pixel, it will generate extra phase change based on the phase change generated by the platform motion. The extra phase change generated by the moving target would be detected in comparing the two PDMs, and thus the moving target is detected. Simulations conducted confirm that the proposed method can detect ground moving targets with very low speeds.