Cramér-Rao bounds for estimating velocity and direction with a bistatic MIMO radar

We derive Cramér-Rao bounds (CRB) expressions for the velocity (Doppler shift), and direction of a point target using a bistatic multiple-input multiple-output (MIMO) radar in this paper. First, we introduce the signal and noise models which satisfy the space-time separability conditions. Then, general CRB expressions are derived for a narrowband signals with the above signal and noise models. We find that the directional parameters are uncoupled with Doppler shift for the space-time separable signal and noise models. However, the directional parameters are usually coupled with each other, i.e., the direction-of-departure (DOD) with direction-of-arrival (DOA) and the azimuth angles the elevation angles are ordinarily coupled. Fortunately, the uncoupled direction estimation can be gotten by the specifical antennas placement.