Experimental study of multiple paths by a bistatic method of synthetic aperture

A method for characterizing the spatial distribution of ground clutter around an omnidirectional antenna is described. The bistatic method is derived from that implemented in side looking radar. Absolute aircraft movement and movement in relation to a point on its trajectory are ensured by inertial systems and trajectography radar. Coherence of the transmitter and receiver is achieved by use of two atomic clocks. Signal processing consists of the following operations: (1) search for pulses corresponding to a scatterer M having a given position; (2) generating a replica corresponding to the theoretical phase evolution of these pulses; and (3) product and integration. This series of operations is repeated for all the possible positions of the point M. Tests over three types of terrain show good distinction between ground echoes with a low backscattering coefficient and those with a high reflectivity coefficient.