瞬变电磁法“#21069;沿”#38382;题与拖拽式系统关键技术研究

项目名称： 瞬变电磁法“#21069;沿”#38382;题与拖拽式系统关键技术研究

项目编号： No.40874094

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 无线电电子学、电信技术

项目作者： 付志红

作者单位： 重庆大学

项目金额： 49万元

中文摘要： 提出瞬变电磁法"前沿"问题- - 前沿发射技术、前沿利用。提出了无源恒压钳位技术和单极性梯形场源技术，研究大功率、单极性、高陡度、线性沿、恒流、前后沿高度一致的场源，对系统的轻便化和高效率产生重要影响；提出宽频恒幅交流方波电流源，可用于频域电磁法仪器；研究了整流装置控制理论，可用于高功率电磁法系统。研究了瞬变电磁法小线圈装置过渡过程影响，分析了线圈有效半径与线圈匝数的关系。提出阻尼变换法的电路参数动态求解算法。提出反卷积的瞬变电磁信号过渡过程校正技术，消除早期信号过渡过程。提出了一种小线框的发送接收弱耦合装置，可消除互感影响。研究了基于Ansoft Maxwell 3D的瞬变电磁法三维正演，可实现瞬变电磁早期信号的场路混合仿真。提出TEM实时成像概念，研究斜阶跃场源全程视电阻率直接计算方法，神经网络非线性方程求解和快速成像技术，研究了长偏移距瞬变电磁法全区视电阻率的二分搜索数值算法。基于高速信号处理平台，建立拖拽式系统原型，开展了探地雷达、GDP32和原型系统对比实验，证明原型系统在浅层探测具有较高分辨率。课题立足地面拖拽式TEM系统，对海洋和航空TEM的发展有一定促进作用。

中文关键词： 瞬变电磁法;梯形脉冲;拖曳式;过渡过程;快速成像

英文摘要： These problems related rising edge is put forward, including the transmitter technology and the application of rising edge.A serise of apssive clamping voltage source, unpolar trapezoid pulse source and wide frequency constant amplitude pulse current source are proposed. With high linearity of trailing edge, adjustable slope of trailing edge and short turn-off delay time, these sources can be used in TEM and CSAMT. The distributed parameters of receiver coil could lead to the time delay of starting point of the effective sampling and the loss of the shallow exploration information. Receiver coils model are established to analyze the apparent resistivity error. The relationship between the apparent resistivity error and the radius of receiver device is given. The result shows that the affect of distributed capacitance to apparent resistivity calculation is small.The effective radius curve with different effective area is given to guide the optimization of device parameters.So, a weak coupling device of transmitting and reciving coil, a dynamic detecting technology for reciver coil parameters and a transition process correction technology based on deconvolution are proposed, which can prompt the shallow detecting. A mixed modling method for electromagnetic and circiut based on Ansoft Maxwell 3D is proposed, which can be used to research early signal of TEM. The research of early signal correction and fast imaging algorithm is in progress. The transient response of a homogeneous half-space excited by a ramp current waveform is proposed. A numerical method for the all-time apparent resistivity and apparent resistivity fast algorithm based on neural network are proposed. which has been proved the validity and feasibility by electromagnetic model analysis software and experiment. Based on VHS-ADC high speed signal processing platform, a towed transient electromagnetic prototype system is established. In practical experiments, the prototype system demonstrates equivalent performance compared to USA GDP-32 system and Canada V8 system, and is more suitable for the superficial detecting.

英文关键词： TEM;Unipolar Pulse;Towed;transient process;Fast Imaging