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 dx.doi.org/10.1109/TGRS.2017.2719401
Journal IEEE Transactions on Geoscience and Remote Sensing
Citation
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