Title: A General Sequential Delay-Doppler Estimation Scheme for Sub-Nyquist Pulse-Doppler Radar,
Abstract: Sequential estimation of the delay and Doppler parameters for sub-Nyquist
radars by analog-to-information conversion (AIC) systems has received wide
attention recently. However, the estimation methods reported are AIC-dependent
and have poor performance for off-grid targets. This paper develops a general
estimation scheme in the sense that it is applicable to all AICs regardless
whether the targets are on or off the grids. The proposed scheme estimates the
delay and Doppler parameters sequentially, in which the delay estimation is
formulated into a beamspace direction-of- arrival problem and the Doppler
estimation is translated into a line spectrum estimation problem. Then the
well-known spatial and temporal spectrum estimation techniques are used to
provide efficient and high-resolution estimates of the delay and Doppler
parameters. In addition, sufficient conditions on the AIC to guarantee the
successful estimation of off-grid targets are provided, while the existing
conditions are mostly related to the on-grid targets. Theoretical analyses and
numerical experiments show the effectiveness and the correctness of the
proposed scheme.