Comments on SAR signal and noise equations

The radar equation is revisited for synthetic aperture radar (SAR). The results apply to systems with: orbital or aircraft geometry; arbitrary pulse shape and antenna weighting; and arbitrary filter weighting functions. Processing gain is defined. Expressions are derived for the image levels corresponding to average additive noise, the peak and the integral of a point scatterer (signal), and the average level of distributed scattering (clutter). Scene statistics covered include both the wide sense stationary case, and the nonstationary case that is more representative of typical applications. It is shown that there is a fundamental and simple equivalence between a SAR´s response to clutter, and the integrated impulse response