本文關(guān)鍵詞： 探地雷達(dá) 自適應(yīng)預(yù)測誤差反褶積 多次波識別 多次波壓制　出處：《中國地質(zhì)大學(xué)(北京)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：探地雷達(dá)技術(shù)是一種非侵入淺表地球物理探測技術(shù),它利用超高頻脈沖電磁波(106-109Hz)來確定介質(zhì)的分布規(guī)律。當(dāng)存在介電常數(shù)相差較大的界面時,探地雷達(dá)的接收天線便會收集到多次波,常見的該類介質(zhì)包括空洞、金屬、管線、含水層、低速薄層等。目前探地雷達(dá)數(shù)據(jù)采集多選用剖面法,得到的數(shù)據(jù)僅能表現(xiàn)反射面的起伏變化,但數(shù)據(jù)中不含電磁波速度等信息。因此在識別多次波時,能夠利用的信息很少,存在很大的識別難度。目前探地雷達(dá)剖面數(shù)據(jù)中多次波的壓制多借鑒地震數(shù)據(jù)的處理方式,但雷達(dá)數(shù)據(jù)相比于地震數(shù)據(jù)又有很多不同,它的超高頻、短波長以及采集方式的不同使得地震數(shù)據(jù)的處理方式不能完全應(yīng)用于雷達(dá)數(shù)據(jù)。多次波的存在嚴(yán)重干擾著有效信息的識別,如果壓制處理不完全還會損傷有效信息,造成解釋陷阱。隨著探地雷達(dá)技術(shù)的應(yīng)用日益廣泛,其獲得數(shù)據(jù)中的多次波問題也越顯突出,而目前關(guān)于探地雷達(dá)多次波的識別特征和壓制方法的研究卻很少,因此研究探地雷達(dá)多次波的識別及壓制方法就變得更有意義。本文為研究探地雷達(dá)剖面中多次波的周期性和非周期性特征,針對地表與地下地層呈水平狀態(tài)、地下反射層與地表傾向不一致等情況下,多次波所表現(xiàn)出的形態(tài)差別明顯的問題,設(shè)計了多個不同的地質(zhì)模型進(jìn)行數(shù)值模擬,分析研究了數(shù)據(jù)中多次波的識別特征。同時針對整個剖面中非周期性多次波的的壓制問題,提出了自適應(yīng)預(yù)測誤差反褶積技術(shù)。該技術(shù)在預(yù)測反褶積技術(shù)的基礎(chǔ)上進(jìn)行了改進(jìn),借助于LMS最小均方算法,在循環(huán)迭代的過程中更新預(yù)測濾波因子。該技術(shù)相比于只能設(shè)置單一預(yù)測步長一步求取預(yù)測濾波因子的預(yù)測反褶積方法,具有多次波預(yù)測準(zhǔn)確,壓制效果好的特點(diǎn);相比于設(shè)置初始濾波因子為O的自適應(yīng)反褶積技術(shù),具有計算速度快、迭代次數(shù)少的特點(diǎn)。分別將該技術(shù)應(yīng)用于正演數(shù)據(jù)中周期性和非周期性多次波的壓制處理中,驗(yàn)證了該技術(shù)能夠較好地壓制層間多次波和自由表面多次波。之后將該技術(shù)應(yīng)用于空洞模型物理實(shí)驗(yàn)數(shù)據(jù)和傾斜地層模型物理實(shí)驗(yàn)數(shù)據(jù)中,壓制了數(shù)據(jù)中周期性和非周期性的自由表面多次波。最后在處理巴丹吉林沙漠沙丘內(nèi)部結(jié)構(gòu)探地雷達(dá)探測數(shù)據(jù)時應(yīng)用了該技術(shù),順利完成數(shù)據(jù)中非周期性自由表面多次波的壓制任務(wù)。
[Abstract]:Ground penetrating radar (GPR) is a non-invasive shallow geophysical detection technique, which uses ultra-high frequency pulsed electromagnetic waves 106-109 Hz to determine the distribution of media. The receiving antenna of the ground penetrating radar will collect multiple waves. The common types of media include holes, metals, pipelines, aquifers, low-speed thin layers, etc. At present, the profile method is often used for data collection of ground penetrating radars. The obtained data can only show the fluctuation of the reflection surface, but there is no information such as the velocity of the electromagnetic wave in the data, so there is very little information that can be used in the identification of multiple waves. At present, the suppression of multiple waves in ground penetrating radar profile data uses for reference the processing methods of seismic data, but the radar data is different from seismic data in many ways, and its ultra-high frequency (UHF). Because of the difference of short wavelength and acquisition method, seismic data processing method can not be applied to radar data completely. The existence of multiple waves seriously interferes with the recognition of effective information, and if the suppression processing is not complete, the effective information will be damaged. With the increasing application of ground penetrating radar (GPR) technology, the problem of multiple waves in the acquisition of GPR data becomes more and more prominent, but there are few researches on the identification characteristics and suppression methods of GPR multiples. In order to study the periodic and aperiodic characteristics of multiple waves in GPR profiles, this paper aims at the horizontal state of ground surface and underground strata. Under the condition that the underground reflection layer and the surface inclination are not consistent, many different geological models are designed for numerical simulation. The recognition characteristics of multiples in data are analyzed and studied. At the same time, an adaptive prediction error deconvolution technique is proposed for the suppression of non-periodic multiples in the whole section, which is improved on the basis of predictive deconvolution technology. With the aid of the LMS minimum mean square algorithm, the predictive filtering factor is updated in the process of cyclic iteration. Compared with the predictive deconvolution method, which can only be calculated by a single prediction step size, it has the accuracy of multiple prediction. Compared with the adaptive deconvolution technique which sets the initial filter factor O, it has a fast calculation speed. The technique is applied to the suppression of periodic and aperiodic multiples in forward data, respectively. It is proved that this technique can suppress interlayer multiple and free surface multiple well, and then it is applied to the experimental data of cavity model and inclined stratum model. The periodic and aperiodic free surface multiples in the data are suppressed. Finally, the technique is applied to the processing of the data from the ground penetrating radar (GPR) in the dunes of the Badanglin Desert. Successfully completes the data non-periodic free surface multiple suppression task.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：P631.3

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本文編號：1504588