Target Detection Improvement using Synchrosqueezing Transform based IF Estimation in SFCW Radars

Stepped frequency continuous wave (SFCW) radar sensors have attracted much attention recently in short range applications, such as ground penetration radar (GPR) due to its advantages in reducing hardware complexity and improving performance. Traditional data processing methods for these radars use Fourier transform to derive range profiles from the acquired frequency-domain data. This method has its limitations for weaker signal detection as the weaker targets are contaminated by noise and sidelobes of the stronger targets. This paper proposes Fourier Synchrosqueezing Transform and Frequency Ridge detection based instantaneous frequency (IF) estimation method for denoising, and improving target detection capabilities of a stepped frequency radar. The effectiveness of the proposed method is validated on simulated and real GPR data. The results show that the proposed method can regenerate range profiles from noisy frequency-domain data keeping target amplitudes and phase unaffected while significantly reducing the noise (by upto 20 dB) even for received signal Signal-to-Noise Ratio (SNR) as low as −5 dB, and was able to effectively cancel out the effect of unwanted returns, such as antenna coupling/surface return.