A Theoretical Analysis and Experimental Results of a Frequency Stepping Method for Radar Scattering Measurements

摘要

When a large, complex target is rotated to obtain a radar cross section (RCS) pattern, the observed RCS typically exhibits violent oscillations. Significant RCS data may be obscured by the oscillations. These oscillations may be smoothed through the use of a frequency-stepping technique in which the radar frequency is shifted from pulse to pulse. The result is an RCS pattern in which the characteristics of individual scatterers are emphasized rather than the interactions between the scatterers. An ancillary result of the frequency-stepping technique is that it may be used to obtain greatly improved range resolution. Instrumentation requirements include a stairstep voltage waveform generator, a voltage-tuned oscillator, a narrowband filter, and a moving corner reflector. The results of frequency stepping measurements on a two-element interferometer, a target with theoretically predictable back scattering characteristics, correspond closely to predicted results. Predictable features appear on frequency-stepping measurements of a vehicle mock-up. (Author)