Near-optimal Range Migration and Doppler Ambiguity Compensation for FMCW Radars

Abstract

High velocity targets suffer from range migration in radars designed for high range and velocity resolution. Such scenarios are becoming common in modern radars such as automotive, airborne and spaceborne radars. Range migration is a very adverse phenomenon resulting in SNR loss, smearing in the range and velocity dimensions, erroneous localization and over-estimated range extent. We start from an exact model of a received FMCW signal, taking all higher order terms into account, and develop low-complexity optimal and near optimal matched filters to mitigate the range migration. We show by simulation that our solution focuses correctly the target energy to a single range-Doppler cell and, in addition, can be used outside of the non-ambiguous Doppler interval to focus Doppler-ambiguous targets correctly and with very low sidelobes.