Range-spread target detector using the frequency rate function

In high-resolution radar systems, stretch processing technique is generally used to process the returned signals of a range-spread target. Consequently, this results in mixer outputs that consist of several linear frequency modulation components with a small frequency rate (FR). The authors define an FR function to transform a signal from the time domain into the FR domain and discuss the FR range of a discrete signal. Then an interesting phenomenon is found in the FR domain, that is, the mixer output is concentrated in a low FR region, while the Gaussian noise spreads over the entire FR region. Therefore, a range-spread target detector has been proposed that regards the integration of the values in a vicinity of zero FR as the test statistic. This detector uses a single mixer output and thus has the ability to detect the target with a high velocity. Finally, the proposed detector is evaluated by recorded radar data. Experimental results show that the proposed detector outperforms the detectors using the high-resolution range profile.