高频地波雷达海态反演算法研究

发布时间：2018-01-08 17:08

本文关键词：高频地波雷达海态反演算法研究　出处：《中国海洋大学》2014年硕士论文　论文类型：学位论文

【摘要】：高频地波雷达，工作于高频(3～30MHz)频段，利用垂直极化电磁波沿海面绕射传播特性，能够探测到视距以外的区域，因此又称其为高频超视距雷达。同其它的海洋监测设备相比，高频地波雷达具有探测距离远、监测面积大和投资较少的优点，同时由于高频地波雷达架设在岸边或置于移动平台上，系统工作基本不受自然环境的影响，因此能够对海洋进行全天候的实时监测，在监测我国专属经济区、维护国家权益、保护海洋环境等方面具有重要作用。近几十年来，高频地波雷达的研究取得了长足的发展，例如运动目标航迹的实时监测、海表面矢量流场和风场的实时测绘等，但海浪谱反演及新体制雷达信号处理等方面所涉及的部分问题仍然处于研究探索阶段。本文针对高频地波雷达海态反演方面现存的问题，进行了以下两项研究工作： 1.岸基高频地波雷达海浪谱反演。在岸基高频地波雷达海浪谱反演问题中，广泛采用的Barrick后向散射公式属于二维第一类非线性Fredholm积分方程。此类积分方程的解在本质上是不适定的，加之高频雷达二阶回波信号信噪比较低，使得反演海浪谱存在解不稳定的问题。本文提出了一种稳定且低复杂度的反演算法，此算法首先根据高频雷达一阶回波谱测量海浪方向，并将其引入积分方程求解过程，减少了求解变量的个数，降低了反演算法的复杂度。为解决反演结果不稳定的问题，，本文使用了Tikhonov正则化方法并利用广义交叉验证法确定其正则化系数。通过在不同测试条件下对反演算法的仿真测试分析，表明此方法具有运算量小、稳定性好的特点。 2.舰载高频地波雷达海流测量。根据一阶布拉格峰展宽原理，当舰载高频地波雷达平台以恒定速度运动时，我们采用多重信号分类算法确定雷达回波信号的波达方向。在相同方向上，测量信号的速度与平台理论速度的差值是由海流引起的，因此我们可以得到海流在此方向上的径向速度。当平台向前移动时，雷达在不同的位置观测海流，由此获得的海洋表面矢量流。仿真结果表明，该算法在雷达探测的重叠区域性能较好。
[Abstract]:The high frequency ground wave radar, which works in the high frequency range of 30 MHz, can detect the area off the horizon by using the diffraction propagation characteristics of the vertical polarized electromagnetic wave along the coast. Compared with other marine monitoring equipment, HF ground wave radar has the advantages of long detection range, large monitoring area and less investment. At the same time, because the HF ground wave radar is installed on the shore or on the mobile platform, the system work basically is not affected by the natural environment, so it can carry on the real-time monitoring of the ocean all the time, and monitor the exclusive economic zone of our country. Safeguarding national rights and interests and protecting the marine environment play an important role. In recent decades, the research of HF ground wave radar has made great progress, such as real-time monitoring of moving target track, real-time mapping of sea surface vector flow field and wind field, etc. However, some problems related to wave spectrum inversion and radar signal processing are still in the stage of exploration. This paper aims at the existing problems in high-frequency ground wave radar sea state inversion. The following two studies were carried out: 1. Wave spectrum inversion of shore-based HF ground wave radar. The widely used Barrick backward scattering formula belongs to the first kind of nonlinear Fredholm integral equation. The solution of this kind of integral equation is ill-posed in essence. In addition, the signal to noise ratio of the second order echo signal of high frequency radar is low, which makes the inversion of wave spectrum unstable. In this paper, a stable and low complexity inversion algorithm is proposed. In this algorithm, the first order echo spectrum of high frequency radar is used to measure the wave direction, and the method is introduced into the process of solving the integral equation to reduce the number of variables to be solved. In order to solve the problem of instability of inversion results, the complexity of inversion algorithm is reduced. In this paper, the Tikhonov regularization method is used and the regularization coefficient is determined by the generalized cross validation method. The simulation analysis of the inversion algorithm under different test conditions is carried out. It is shown that this method has the advantages of small computation and good stability. 2. Current measurement of shipborne HF ground wave radar. According to the first order Bragg peak broadening principle, when the shipborne HF ground wave radar platform moves at a constant speed. In the same direction, the difference between the velocity of the measured signal and the theoretical velocity of the platform is caused by the current. Therefore, we can get the radial velocity of the current in this direction. When the platform moves forward, the radar can observe the current at different positions, and the resulting vector current on the ocean surface can be obtained. The simulation results show that. The algorithm has good performance in the overlapped region of radar detection.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN958.93

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