波谱仪调制功率谱估计算法性能的仿真研究

基于星载波谱仪海浪方向谱探测原理,仿真了不同海况、风速下的海浪波谱仪接收信号,并采用周期图法、Welch法、AR模型法以及最小方差法共4种不同的调制谱估计方法反演出海浪谱,比较各种调制谱估计方法的海浪方向谱反演性能。仿真结果表明:对于一定方位向下的一维海浪谱反演,不同调制谱估计方法反演海浪谱性能优劣没有绝对的顺序。对于二维海浪谱反演,在成长中海浪条件下周期图法反演性能最差,其他3种方法的反演性能没有绝对优劣顺序;对于成熟风浪,最小方差法在积分能量误差、有效波高误差两个指标上的反演性能最好,在主波波向、主波波长误差上,周期图法反演性能最差,其他3种方法没有绝对优劣顺序。在涌浪条件下,AR模型法反演性能优于其他3种方法。在不同海况下,随着波谱仪中心入射角的下降,反演性能会下降。基于这些仿真结果,本文推荐最小方差法作为充分成长海浪的海浪方向谱反演的调制谱估计方法,AR模型法作为涌浪海浪方向谱反演的调制谱估计方法。

Simulation study on the performance of modulation power spectrum estimation algorithm for the spectrometer

Based on the principle of wave directional spectrum measurement of space borne spectrometer, simulations of signals received by spectrometer are carried out under different sea state conditions and wind speed in this paper. And four different modulation spectral estimation methods, such as periodogram method, Welch method, AR model method and minimum variance method, are used to retrieve the ocean wave spectrum. The inversion performances of various modulation spectral estimation methods mentioned above are compared. The simulation results show that for the one-dimensional wave spectrum inversion, there is no absolute superiority for the wave spectrum performance of the inversion by different modulation spectral estimation methods. And for the two-dimensional wave spectrum inversion, the periodogram method is the worst under the condition of developed ocean wave, and the inversion performances of the other three methods have no absolute superiority. For the mature wind-sea, the minimum variance method has the best inversion performance on the integral energy error and the significant wave height error, while the periodogram method has the worst inversion performance on the dominant wave direction error and the dominant wavelength error. In the swell condition, the AR model method has better performance than the other three methods. In the different sea state conditions, the inversion performance will decrease with the incidence angle. Based on these simulation results, the minimum variance method is proposed to retrieve ocean wave directional spectrum for the case that the sea surface is fully developed, and the AR model method is proposed to retrieve the ocean wave directional spectrum under swell condition.