Outlier-Robust Truncated Maximum Likelihood Parameter Estimation of Compound-Gaussian Clutter with Inverse Gaussian Texture

Abstract

Compound-Gaussian distributions with inverse Gaussian textures, referred to as the IGCG distributions, are often used to model moderate/high-resolution sea clutter in amplitude. In moderate/high-resolution maritime radars, parameter estimation of the IGCG distributions from radar returns data plays an important role in adaptive target detection. Due to the inevitable existence of outliers of high amplitude in radar returns data from targets and reefs, parameter estimation must be outlier robust. In this paper, an outlier-robust truncated maximum likelihood (TML) estimation method is proposed to mitigate the effect of outliers of high amplitude in data. The data are first transferred into the truncated data by removing a given percentage of the largest samples in amplitude. From the truncated data, the truncated likelihood function is constructed, and its maximum corresponds to the TML estimates of the scale and inverse shape parameters. Further, an iterative algorithm is presented to obtain the TML estimates from data with outliers, which is an extension of the ML estimation method in the case that data contain outliers. In comparison with outlier-sensitive estimation methods and outlier-robust bipercentile estimation methods, the performance of the TML estimation method is close to that of the best ML estimation method in the case that data are without outlier, and it is better in the case that data are with outliers.