Application of Joint Time-Frequency Representations to a Maneuvering Air Target in Sea-Clutter: Analysis Beyond FFT
DEFENCE RESEARCH AND DEVELOPMENT CANADAOTTAWA (ONTARIO)
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Traditionally, radar signals have been analyzed in either the time or the frequency domain. Joint time-frequency representations characterize signals over a time-frequency plane. They thus combine time-domain and frequency-domain analyses to yield a potentially more revealing picture of the temporal localization of a signals spectral components. Therefore, for air target returns with time-varying frequency content, the joint time-frequency representations offer a powerful analysis tool. A concise review of time-frequency transforms is provided as background and is needed to appreciate how time-frequency processing methods can improve conventional time or frequency processing methods. The report then describes and illustrates the advantages of using joint time-frequency techniques to analyze a multi-component signal, a noisy signal, and experimental aircraft data. Finally, we use time-frequency analysis techniques for the detection of maneuvering aircraft using HF radar in heavily cluttered regions. We compare the ability of different time-frequency transforms to resolve several experimental aircraft returns. The results clearly demonstrate that time-frequency analysis techniques can significantly improve the detection performance of the HF radar and add considerable physical insight over what can be achieved by conventional Fourier transform methods currently used by HF radars.
- Active and Passive Radar Detection and Equipment