We model the signal received by a FM pulse radar, considering the general case where the transmitter and the receiver are separated and are moving. The electromagnetic wave polarization state change generated by the observed body is also taken into account in the model proposed in this paper. The expression of the received signal is written as the voltage detected on the receiving antenna and is given as a function of time by taking into account the antenna radiation (transmitting antenna and receiving antenna), the polarimetric behavior of the target, and the mobiles velocity effect. Numerical results are presented considering a canonical target or a slightly rough surface using a monostatic or a bistatic configuration to show the accuracy of the theoretical results and to study the velocity effect of the mobiles. ¿ 2000 American Geophysical Union