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Cramér Rao Lower Bound Derivation of Parameter Estimation for Hypersonic Platform SAR-GMTI

The accuracy of parameter estimation of the moving target is an important index to evaluate the performance of ground moving target indication (GMTI) system. On this point, for synthetic aperture radar (SAR) equipped on the hypersonic platform, this paper mainly derives the Cramér Rao lower bound (CRLB) of parameter estimation of the moving target. Firstly, an approximate curved geometric model matched with the platform trajectory is established. Then, the multichannel steering vector of along-track interferometric phase is obtained based on the derivation of the complex response of SAR image. Further, the joint probability density function (pdf) of target parameters is designed, based on which the CRLB of parameter estimation is derived. Finally, the CRLB for the radial velocity estimation is simulated under different signal to clutter ratio (SCR) values and baselines. Meanwhile, its influence on the GMTI performance is further analyzed.