Moving Targets Velocity Estimation Using Aliased Sar Raw-data from a Single Sensor

This paper presents a new methodology to retrieve slantrange velocity estimates for moving targets with speeds inducing Doppler-shifts beyond the Nyquist limit imposed by the Pulse Repetition Frequency (PRF ). The proposed approach exploits the linear dependency of the Dopplershift with the slant-range velocity for each fast-time frequency. Therefore, the echo from a moving target in the twodimensional spectral domain exhibits a skew depending on the target range-speed that is not subject to PRF limitations. By combining the developed scheme to retrieve the slantrange velocity with a methodology proposed elsewhere to estimate the velocity vector magnitude, the full velocity vector is unambiguously retrieved without the need to increase the mission PRF . The effectiveness of the method is illustrated with simulated and real data.