This chapter investigates ground moving target radar modes for surveillance from air-to-ground radar systems. This mode has been important, starting with both Multiple Aperture Surveillance Radar (MASR) and Standoff Target Acquisition System (SOTAS) to detect slow-moving targets in a battlefield environment. Its technical challenges are the detection of slow-moving targets that are masked by the clutter Doppler within the main beam of the radar antenna. A wide range of algorithms have been developed over the past 50 years, as the radio frequency (RF) components and high-speed signal processing techniques have been improved [1]. But as the technology advances, several new algorithms and system architectures were invented, based on the advances in component technologies. These techniques include obtaining high resolution of the targets for discrimination, and moving to longer wavelength radar systems to counter the masking and techniques that the adversary uses to avoid detection [2]. In addition to military ground moving target indication (GMTI) techniques, there are several civilian and geoscience applications for characterizing terrain, forests and ecological measurements using radar images.