  In many radar scenarios, the radar target or the medium is assumed to possess
randomly varying parts. The properties of a target are described by a random
process known as the spreading function. Its second order statistics under the
WSSUS assumption are given by the scattering function. Recent developments in
operator sampling theory suggest novel channel sounding procedures that allow
for the determination of the spreading function given complete statistical
knowledge of the operator echo from a single sounding by a weighted pulse
train.
  We construct and analyze a novel estimator for the scattering function based
on these findings. Our results apply whenever the scattering function is
supported on a compact subset of the time-frequency plane. We do not make any
restrictions either on the geometry of this support set, or on its area. Our
estimator can be seen as a generalization of an averaged periodogram estimator
for the case of a non-rectangular geometry of the support set of the scattering
function.
