本文選題：固定翼航空電磁　切入點(diǎn)：電導(dǎo)率深度成像　出處：《吉林大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：固定翼時(shí)間域航空電磁探測(cè)(Fixed-wing Airborne Time-domain Electromagnetic)是一種基于電磁感應(yīng)定律,以固定翼飛機(jī)為載體的地球物理探測(cè)方法,具有探測(cè)深度深,效率高,成本低等優(yōu)勢(shì),被廣泛應(yīng)用于地質(zhì)勘查,油氣探測(cè)等領(lǐng)域。航空電磁探測(cè)系統(tǒng)在飛行測(cè)量過(guò)程中,由于飛行速度,飛機(jī)姿態(tài),氣壓等因素,引起飛行高度和接收線圈姿態(tài)角度的改變,影響觀測(cè)數(shù)據(jù),使得電導(dǎo)率深度成像(CDI,Conductivity-Depth Imaging)結(jié)果存在誤差。本文在國(guó)家自然科學(xué)基金項(xiàng)目“固定翼時(shí)間域航空電磁探測(cè)整體反演方法研究”的資助下,研究了飛行高度、接收線圈俯仰姿態(tài)角度(pitch)變化引起電磁響應(yīng)變化,而探測(cè)系統(tǒng)無(wú)法準(zhǔn)確獲得pitch、飛行高度,因此本文提出了基于迭代查表法的電導(dǎo)率深度成像算法。主要研究?jī)?nèi)容包括以下方面:基于航空電磁探測(cè)理論,推導(dǎo)了接收線圈任意姿態(tài)角度變化下的三分量一維正演計(jì)算方法;研究了飛行高度變化對(duì)電磁響應(yīng)的影響;研究了接收線圈搖擺(roll),俯仰(pitch),偏航(yaw)角度變化下的電磁響應(yīng)特征。針對(duì)常規(guī)航空電磁系統(tǒng)難以獲得pitch信息,將pitch作為參數(shù)引入到電導(dǎo)率深度成像中,研究了帶pitch的B場(chǎng)雙分量(水平分量Bx、垂直分量Bz)查表CDI算法。正演計(jì)算多個(gè)固定飛行高度各時(shí)間道的Bx-Bz-?-pitch數(shù)據(jù)表,根據(jù)實(shí)測(cè)飛行高度找到對(duì)應(yīng)飛行高度、對(duì)應(yīng)時(shí)間道數(shù)據(jù)表,通過(guò)線性插值得到視電導(dǎo)率(?),根據(jù)擴(kuò)散公式求得成像深度,最終實(shí)現(xiàn)帶pitch的電導(dǎo)率深度成像算法。在高度計(jì)示數(shù)不準(zhǔn)確情況下,將飛行高度和pitch同時(shí)作為參數(shù)引入到電導(dǎo)率深度成像中,研究了帶飛行高度和pitch的迭代查表CDI算法。通過(guò)正演計(jì)算,建立多個(gè)固定飛行高度下各時(shí)間道的Bx-Bz-?-pitch數(shù)據(jù)表和多個(gè)固定俯仰姿態(tài)角度下各時(shí)間道的Bx-Bz-?-height數(shù)據(jù)表。根據(jù)實(shí)測(cè)Bx、Bz電磁響應(yīng)在兩個(gè)數(shù)據(jù)表中進(jìn)行查表迭代計(jì)算,直至最后一次迭代的?、height和pitch全部滿足精度要求,則迭代結(jié)束,得到視電導(dǎo)率,飛行高度和俯仰姿態(tài)角度信息。利用擴(kuò)散公式計(jì)算各層深度,用平均視電導(dǎo)率計(jì)算成像深度,最終實(shí)現(xiàn)帶飛行高度和pitch的迭代查表電導(dǎo)率深度成像算法。仿真結(jié)果表明迭代查表法電導(dǎo)率深度成像不僅優(yōu)于未考慮飛行高度和俯仰姿態(tài)角度誤差下的成像結(jié)果,而且即使獲得比較準(zhǔn)確的飛行高度信息,迭代查表法電導(dǎo)率深度成像精度也提高了10%左右。迭代查表法在獲得視電導(dǎo)率的同時(shí)獲得height、pitch,對(duì)比分析了迭代查表法獲取輔助參數(shù)與系統(tǒng)測(cè)量參數(shù)間誤差;研究了迭代查表法對(duì)系統(tǒng)輔助參數(shù)測(cè)量精度要求;構(gòu)建了一維和準(zhǔn)二維大地模型,驗(yàn)證了在飛行高度初始值滿足精度的要求下,迭代查表法CDI得到的height和pitch與理論值誤差分別在20%和10%范圍內(nèi)。
[Abstract]:Fixed-wing Airborne Time-domain electromagnetic sounding (Fixed-wing Airborne Time-domain electromagnetic) is a geophysical detection method based on the law of electromagnetic induction. It has the advantages of deep detection depth, high efficiency and low cost, so it is widely used in geological exploration. In the course of flight measurement, the flight altitude and attitude angle of receiving coil are changed due to the factors such as flight speed, aircraft attitude, air pressure, etc., which affect the observation data. In this paper, the flight altitude is studied with the aid of the project of National Natural Science Foundation "Research on the whole inversion method of fixed wing time domain aero-electromagnetic exploration", which results in the error of the results of the conductivity depth imaging (CDII) and Conductivity-Dependency Imaging. The change of pitching attitude angle of the receiving coil causes the change of electromagnetic response, but the detection system can not accurately obtain the pitching, flying altitude, In this paper, we propose a depth imaging algorithm for electrical conductivity based on iterative look-up table method. The main research contents are as follows: based on the theory of airborne electromagnetic detection, The three-component one-dimensional forward calculation method for receiving coil with arbitrary attitude angle is derived, and the influence of flight altitude on electromagnetic response is studied. In this paper, the electromagnetic response characteristics of the receiving coil under the change of yaw-yaw-yaw-angle are studied. The pitch is introduced into the conductivity depth imaging because it is difficult for the conventional aeronautical electromagnetic system to obtain the pitch information. In this paper, the CDI algorithm of B field double component (horizontal Bx, vertical Bz) lookup table with pitch is studied. According to the measured flight altitude, the corresponding flight height is found, the corresponding time track data table is obtained, and the apparent conductivity is obtained by linear interpolation. According to the diffusion formula, the imaging depth is obtained, and the conductivity depth imaging algorithm with pitch is finally realized. In the case of inaccurate altimeter indication, the flight altitude and pitch are introduced into the conductivity depth imaging simultaneously as parameters. The iterative lookup table CDI algorithm with flight altitude and pitch is studied. Bx-Bz-? -height data Table. Based on the measured BxBz electromagnetic response, the look-up table is calculated in two tables until the last iteration. The height and pitch all meet the precision requirement, then the iteration ends, and the information of apparent conductivity, flying altitude and pitching attitude are obtained. The diffusion formula is used to calculate the depth of each layer, and the imaging depth is calculated by the average apparent conductivity. Finally, an iterative lookup table conductivity depth imaging algorithm with flight altitude and pitch is implemented. The simulation results show that the iterative look-up table method is not only superior to the imaging results without considering the flight altitude and pitch angle errors, but also the simulation results show that the proposed method is better than that without considering the flight altitude and pitch angle errors. And even if you get more accurate altitude information, The depth imaging accuracy of the iterative look-up table method is also improved by about 10%. The error between the iterative lookup table method and the system measurement parameters is compared and analyzed, while the apparent conductivity is obtained at the same time as the apparent conductivity is obtained by the iterative lookup table method. In this paper, the accuracy requirement of the system aided parameter measurement by the iterative lookup table method is studied, and the one and two dimensional geodetic model is constructed, which verifies that the initial flight altitude value meets the precision requirement. The errors between the height and pitch obtained by CDI and the theoretical values are in the range of 20% and 10%, respectively.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：P631.326

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