本文關(guān)鍵詞：高頻地波雷達(dá)海態(tài)反演算法研究　出處：《中國(guó)海洋大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 岸基高頻地波雷達(dá) 艦載高頻地波雷達(dá) 海浪譜反演 正則化算法 海表面流測(cè)量

【摘要】：高頻地波雷達(dá)，工作于高頻(3～30MHz)頻段，利用垂直極化電磁波沿海面繞射傳播特性，能夠探測(cè)到視距以外的區(qū)域，因此又稱其為高頻超視距雷達(dá)。同其它的海洋監(jiān)測(cè)設(shè)備相比，高頻地波雷達(dá)具有探測(cè)距離遠(yuǎn)、監(jiān)測(cè)面積大和投資較少的優(yōu)點(diǎn)，同時(shí)由于高頻地波雷達(dá)架設(shè)在岸邊或置于移動(dòng)平臺(tái)上，系統(tǒng)工作基本不受自然環(huán)境的影響，因此能夠?qū)Ｑ筮M(jìn)行全天候的實(shí)時(shí)監(jiān)測(cè)，在監(jiān)測(cè)我國(guó)專屬經(jīng)濟(jì)區(qū)、維護(hù)國(guó)家權(quán)益、保護(hù)海洋環(huán)境等方面具有重要作用。 近幾十年來(lái)，高頻地波雷達(dá)的研究取得了長(zhǎng)足的發(fā)展，例如運(yùn)動(dòng)目標(biāo)航跡的實(shí)時(shí)監(jiān)測(cè)、海表面矢量流場(chǎng)和風(fēng)場(chǎng)的實(shí)時(shí)測(cè)繪等，但海浪譜反演及新體制雷達(dá)信號(hào)處理等方面所涉及的部分問題仍然處于研究探索階段。本文針對(duì)高頻地波雷達(dá)海態(tài)反演方面現(xiàn)存的問題，進(jìn)行了以下兩項(xiàng)研究工作： 1.岸基高頻地波雷達(dá)海浪譜反演。在岸基高頻地波雷達(dá)海浪譜反演問題中，廣泛采用的Barrick后向散射公式屬于二維第一類非線性Fredholm積分方程。此類積分方程的解在本質(zhì)上是不適定的，加之高頻雷達(dá)二階回波信號(hào)信噪比較低，使得反演海浪譜存在解不穩(wěn)定的問題。本文提出了一種穩(wěn)定且低復(fù)雜度的反演算法，此算法首先根據(jù)高頻雷達(dá)一階回波譜測(cè)量海浪方向，并將其引入積分方程求解過程，減少了求解變量的個(gè)數(shù)，降低了反演算法的復(fù)雜度。為解決反演結(jié)果不穩(wěn)定的問題，，本文使用了Tikhonov正則化方法并利用廣義交叉驗(yàn)證法確定其正則化系數(shù)。通過在不同測(cè)試條件下對(duì)反演算法的仿真測(cè)試分析，表明此方法具有運(yùn)算量小、穩(wěn)定性好的特點(diǎn)。 2.艦載高頻地波雷達(dá)海流測(cè)量。根據(jù)一階布拉格峰展寬原理，當(dāng)艦載高頻地波雷達(dá)平臺(tái)以恒定速度運(yùn)動(dòng)時(shí)，我們采用多重信號(hào)分類算法確定雷達(dá)回波信號(hào)的波達(dá)方向。在相同方向上，測(cè)量信號(hào)的速度與平臺(tái)理論速度的差值是由海流引起的，因此我們可以得到海流在此方向上的徑向速度。當(dāng)平臺(tái)向前移動(dòng)時(shí)，雷達(dá)在不同的位置觀測(cè)海流，由此獲得的海洋表面矢量流。仿真結(jié)果表明，該算法在雷達(dá)探測(cè)的重疊區(qū)域性能較好。
[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.
【學(xué)位授予單位】：中國(guó)海洋大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN958.93

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本文編號(hào)：1397953