2017, 39(10): 2294-2301.
doi: 10.11999/JETI170118
Abstract:
A method is proposed to analyze and assess the SAR resolution, which considers the statistical characteristics of the distributed targets and the number of multi-look. The joint probability density function of two points on the amplitude radio, phase difference, correlation coefficient, and the number of multi-look is deduced from the SAR complex scattering echo signal. Based on the study of the SAR separable probability and the PDF, a mathematical model is built that reflects the mathematical relationship between the SAR resolution and the statistical properties of the targets and the number of multi-look. Considering the condition that the points can be separated, the influence that the statistical properties of SAR distributed targets and multi-look processing have on SAR resolution is discussed. From the numerical results, when the distance between targets is less than the traditional resolution, the targets also can be distinguished; and when the distance is larger than the traditional resolution, the targets may not be distinguished. The effect of multi-look processing is equivalent to increasing the relevance between the targets, and it also has great influence on SAR resolution. The separable probability can reflect the resolution performance correctly and is important for designing and evaluating the SAR system.