Study of wind direction factor based on sea clutter in littoral environments

摘要

Wind direction factor, as a part of some empirical sea clutter models of the normalised radar cross-section (NRCS), is closely related to wind direction angle, grazing angle and radar wavelength. The use of the low-grazing-angle (LGA) sea clutter measured by UHF-band radar on the Lingshan island to discuss the characteristic of the wind direction factor is investigated. The results indicate that the upwind-to-crosswind ratio of NRCS, which is calculated by the empirical model, could not provide a good fit for grazing angles <10 degrees. It was found that the ratio obtained from measured data varies with the sea state (SS) at the same grazing angle, conversely the empirical models was constant. Based on deep analysis of the results, we finally find out the influence of SS could not be ignored. In addition, some suggestions to improve sea clutter model of littoral environments were proposed for practical applications.