Compensation of Ambiguities in Fast ISAR Measurements

Scattering mechanisms of radar targets are analysed using Radar Cross-Section (RCS) images. Those measurements are performed in an anechoic chamber to avoid external influences having an impact on the results. An unambiguous range covering the whole measurement chamber to avoid aliasing effects can be accomplished depending on the frequency step size. Taking into account a high bandwidth to enable a fine range resolution, this results in a large number of required frequency points. A reduction of the amount of frequency points based on the physical target size instead of the whole facility dimensions is suggested. Therefore, an unambiguous measurement is required but it has to be measured only once and serves as reference. This allows to measure the remaining view angles ambiguously and mitigate arising aliasing effects using the reference. Hence, the measurement time is reduced or a lower intermediate frequency bandwidth allows increasing the dynamic range of RCS measurements.