Inventors:
August W. Rihaczek - Rolling Hills CA
Assignee:
The United States of America as represented by the Secretary of the Air
Force - Washington DC
International Classification:
G01S 1389
Abstract:
This invention involves a method of processing radar returns to form two-dimensional images of targets such as ground vehicles, aircraft, ships, and so forth. Resolution in one dimension is provided by range resolution, and resolution in the other dimension is provided by Doppler resolution. Man-made targets such as ground vehicles or ships consist of scattering centers which are extended smooth plates, long edges, rods and the like. These scattering units typically are so large compared with the radar wavelength that they have a highly lobed backscattering pattern. When the processing time is increased in order to achieve higher Doppler resolution, it is possible to observe over the processing time a full or even more than one sidelobe of the backscattering pattern. Doppler resolution theory shows that under these circumstances the responses of scatterers are smeared out into meaningless background interference, so that image detail is lost. The present invention avoids this problem by analyzing the signal in segments much shorter than used with conventional processing.