This paper derives the Cramér-Rao lower bound (CRLB) for a general multichannel spaceborne synthetic aperture radar system for ground moving-target indication and provides a theoretical analysis of across-track velocity estimation for RADARSAT-2 and a fictitious satellite. The signal model assumes a deterministic target signal in Gaussian clutter and noise. In estimation theory, the CRLB provides a lower bound on the achievable variance of any unbiased estimator. An estimator that achieves this bound is called efficient; however, there is no guarantee that an efficient estimator can be found. Nonetheless, the theoretical variance of the efficient estimator provides a good measure of the capability of the system and serves as a valuable system performance validation tool. Even if an efficient estimator cannot be found, for radar systems, the CRLB provides a necessary, but not sufficient design baseline for measurement parameters, such as the number of subapertures for transmit and receive, power levels, pulse-repetition frequency, and so on. CRLBs for a limited number of system configurations for RADARSAT-2 and TerraSAR-X are presented by Cerutti-Maori et al. and Ender et al.; however, the complete analytical form of CRLB for a general system, which can be readily applied to an arbitrary antenna switching configuration, has not been previously derived.

Additional Metadata
Keywords Antenna switching, Cramér-Rao bounds, ground moving-target indication (GMTI), radar detection, radar position estimation, radar signal analysis, radar velocity measurement, spatial diversity, synthetic aperture radar (SAR)
Persistent URL
Journal IEEE Transactions on Geoscience and Remote Sensing
Rashid, M. (Mamoon), & Dansereau, R. (2017). Cramér-Rao Lower Bound Derivation and Performance Analysis for Space-Based SAR GMTI. IEEE Transactions on Geoscience and Remote Sensing, 55(11), 6031–6043. doi:10.1109/TGRS.2017.2719401