Combination of the biologically inspired coupled system and high-frequency surface wave radar at signal level

Virtual aperture extension of small aperture array has attracted wide attention in high-frequency surface wave radar (HFSWR). A biologically inspired coupled (BIC) system is employed to virtually extend the array aperture. However, the existing researches on BIC only consider the array signal processing model and do not combine it with actual radar signal principle. To indeed apply the BIC system to HFSWR, two detailed methods which combine the BIC and HFSWR at signal level are proposed. A three-dimensional signal model of HFSWR considering array processing was established and the entire signal processing was derived. Then, two combination methods, namely fast-time domain (FTD)-BIC and slow-time domain (STD)-BIC are proposed. The former implements the BIC before fast-time processing, while the latter implements the BIC before slow-time processing. The authors demonstrate that they can virtually extend the array aperture without affecting the target detection. Meanwhile, their capabilities in multi-target scenarios are analysed and satisfactory conclusions are obtained. By numerical simulations and experiments, the array aperture and range-Doppler (RD) spectrum of the standard HFSWR and BIC-HFSWR are compared. The results show that while the performance of their RD spectrum is almost the same, BIC-HFSWR has an enlarged virtual aperture than standard HFSWR.