Research Progress on Sub-band Fusion Technology for Ultra-wideband Radar Signals

Ultra-wideband signal which improves radar range resolution and facilitates target recognition is attractive in radar applications. However, it is expensive and unrealistic to construct ultra-wideband radar hardware. Therefore, sub-band fusion technology becomes an alternative because of its low construction cost and high computation accuracy. Sub-band fusion technology involves several key procedures, including sub-band fitting, multi-band coherent processing, and ultra-wideband extrapolation. For sub-band fitting, several existing electromagnetic scattering models can be used and their parameters are extracted using parameter estimation algorithms. It is noted that system errors and asynchronization between sub-bands cause incoherence between multi-bands. To compensate incoherence between multi-bands, sub-bands are extrapolated and a mutual coherence model should be constructed and estimated so that coherence between multi-bands can be restored. Finally, ultra-wideband extrapolation is realized by joint processing of coherent multi-bands. In this paper, research progress on the aforementioned procedures is summarized. Performance of existing algorithms are analyzed and compared. Finally, multi-band fusion results based on simulated data as well as static-range data and future discussion are presented.