Deriving power fluctations from Swerling Models in an FMCW Radar

Dear all,

           Most radar books (skolnik, currie) contain recieved signal
amplitude fluctuation distributions derived from Swerling RCS
fluctuation models for pulsed radars. However, I believe these do not
apply to an FMCW radar. Does anybody know (or some references) how to
derive the resulting power fluctuation pdfs given the Swerling models
for an FMCW radar ? 

Thanks in advance, 

John.