Velocity estimation and compensation approach for SFW radar visa IGSS

Stepped frequency waveform (SFW) has been widely utilized in millimetre-wave radars, achieving high-resolution range profiles without expanding the radar's instantaneous bandwidth. Nevertheless, the inherent large time-bandwidth product associated with SFW results in significant ranging errors and energy dispersion, impeding its effectiveness in detecting high-speed targets. Spurred by this limitation, this study introduces an innovative velocity estimation method that employs the fractional Fourier transform (FrFT) to overcome these drawbacks. Specifically, by harnessing the Doppler signature of a moving target, which appears as a chirp signal with a frequency rate directly proportional to the target's velocity, FrFT provides precise velocity measurements. Following the velocity estimation, a compensation process is implemented using the derived metrics, after which the inverse fast Fourier transform locates the target accurately. Furthermore, an iterative algorithm based on the golden section search technique has been developed to enhance the computational efficiency of determining the optimal order for the FrFT. The validity of the proposed method is confirmed through simulation data, demonstrating that the developed approach can accurately estimate the velocity of high-speed targets with a notably reduced computational complexity.