Impact of experimentally measured Doppler spectrum of ground clutter on MTI and STAP

The experimental measurement of the Doppler spectrum of the ground clutter has revealed an exponential shape in contrast to the commonly used Gaussian shape. The goal of this paper is to investigate its consequences on two practical applications, namely: clutter cancellation and target detection with coherent optimum MTI on ground based radar and with space-time adaptive processor (STAP) on airborne radar. The experimental evidence of the Doppler spectrum for ground clutter is included and the improvement factor of an optimum MTI is compared for Gaussian shaped as well as exponentially shaped clutter spectrum. The loss of improvement factor (IF) and the reduction of the target visibility as a function of the target Doppler frequency and of the number of integrated pulses are evaluated. A similar analysis is also presented for the case of an airborne radar equipped with a digital beam forming and a STAP.