A method of building radargram with the ability of object discrimination for the step-frequency radar

A novel signal processing method to build radargram for a step-frequency radar is presented. The conventional technique of obtaining radargram that employs an inverse Fourier transform of separate A-scans has been modified by the derivation of an additional time-dependent function. To this end, the Fourier transform is performed on both measured complex reflection coefficient data and also the same data in which the phase term is replaced by one representing only distance to the target. The difference of arguments of the obtained complex functions yields the desired radargram depending mostly on the phase shift occurring at the reflection from the target. This radargram was found to be useful for the target characterization while the conventional radargram serves as before for detection and localization of the target. The validity of the method is demonstrated in several simulated and experimental examples. Due to relative simplicity of the data processing technique, the method is rather fast and thus attractive from a practical viewpoint.