Micro-Doppler removal in radar imaging in the case of non-compensated rigid body acceleration

The micro-Doppler (m-D) effect, commonly caused by fast moving reflectors, can significantly decrease the readability of rigid body in ISAR/SAR radar images. We revisit an L-statistics based micro-Doppler removal approach, producing excellent results in separation of the stationary rigid body from the m-D. In the case of non-compensated target acceleration, rigid body components become non-stationary, commonly with linear frequency modulation. The Local Polynomial Fourier Transform (LPFT) can be exploited for the estimation of the unknown chirp-rate needed for the acceleration compensation. To this aim, we present a simple iterative procedure based on the LPFT concentration measure. It is an alternative to the direct search approach for the estimation of the LPFT demodulation parameter, improving the estimation accuracy and reducing the numerical complexity of the approach. Numerical examples verify the presented theory.