A LoGI Phase Unwrapping Algorithm for Ku-SFCW Radar Interferometry Measurement of Wave Height

The monitoring of wave height is of great significance in multiple fields such as marine safety, ecological protection, and climate change response. The ground based (GB) has the advantage of high range resolution. The built TI millimeter-wave (mmWave) radar system has achieved 1-D time-series wave height measurement, and the consistency between simulation and experimental results demonstrates the capacity of wave height measurement. Another independently built Ku-band stepped frequency continuous-wave (Ku-SFCW) radar system has achieved 2-D wave height time-series interferometry measurement. Given the traditional fast Fourier transform (FFT) algorithm, combined transport of intensity equation (TIE) with a Gaussian operator, a Laplacian of Gaussian (LoG) phase unwrapping (PU) expression was derived. Then, the 2-D LoG iteration (LoGI) PU algorithm was proposed by using an iterative strategy. The experimental results show that the LoGI algorithm is superior to the FFT algorithm and prove the effectiveness of Ku-SFCW radar system interferometry measurement of wave height. The experimental results proved the superiority of the 2-D LoGI PU algorithm in inverting the Kelvin wake wave height of the ship measured by the Ku-SFCW radar system under laboratory conditions.