石油钻井雷达收发前端设计

发布时间：2018-12-13 03:23

【摘要】：石油钻井雷达的研究对于矿产和地下探测具有国家战略意义,基于冲激体制的石油钻井雷达具有分辨率高兼穿透能力强的特点。论文主要围绕着基于冲激体制的石油钻井雷达系统关键技术展开设计,通过阐述石油钻井雷达系统的特点和关键指标的计算;研制石油钻井雷达的冲激信号脉冲源,时变衰减接收机的射频模块,探索石油钻井雷达成像技术。研制低触抖动的冲激信号源;讨论几种常见的超宽带信号数学形式、产生方法、以及频谱分析;分析高斯信号在地质的衰减特性与传播特性,用CST仿真各阶高斯信号在地质中对目标散射特性;最终确定雷达系统的冲激信号源的数学模型。通过分析雪崩晶体管的雪崩效应、雪崩电路工作机理与工作点的动态变换过程,在Marx电路基础上研制一个低触发抖动的冲激信号脉冲源。通过理论计算Marx电路各个指标,并用Orcad对Marx电路进行仿真优化。利用驱动隔离电路与雪崩三极管设计驱动电路降低触发抖动,利用雪崩二极管与滤波器的构造脉冲整形电路实现窄脉宽。选择雪崩晶体三极管FMMT415和雪崩晶体二极管P4SMA540A研制冲激信号源在50欧姆的负载上实测峰值电压为690 V、半峰值脉冲宽度为500 ps、触发抖动32 ps。研制时变衰减接收机射频前端;基于冲激信号在地质中的传输特性和目标的反射特性分析,计算整个石油钻井雷达系统指标,分析冲激体制雷达的特点。提出用MA4P7455研制时变衰减电路和低噪声系数链路增加接收机的动态范围与探测距离,合理分配整个接收机的指标,利用ADS对整个链路进行仿真优化。时变衰减电路的控制信号是由自举电路与电压跟随器设计的三角波电路产生,这个三角波电路实现在50 ns-2 us可调的上升时间。整个时变衰减接收机的射频前端工作带宽是30 MHz-1 GHz、增益动态范围-15dB-53dB,增益模块的噪声系数0.82 dB,接收机噪声系数3.6 dB;系统灵敏度-83.59 dBm。成像算法上的研究主要是从对目标的散射实验当中得出目标的反射信号数学函数形式固定、能量集中在300 MHz-800 MHz之间;基于此利用傅里叶滤波法可以有效对目标信号的提取。同时利用时变放大、相关函数、中值滤波法可以有效抑制杂波;利用中值滤波法还可以产生背景信号,有效解决雷达移动过程中目标的成像问题。
[Abstract]:The research of petroleum drilling radar is of national strategic significance for mineral and underground exploration. The petroleum drilling radar based on impulse system has the characteristics of high resolution and strong penetration ability. This paper mainly focuses on the design of the key technology of petroleum drilling radar system based on impulse system, and expatiates on the characteristics of petroleum drilling radar system and the calculation of key indexes. The impulse signal pulse source of petroleum drilling radar and the RF module of time-varying attenuation receiver are developed to explore the imaging technology of petroleum drilling radar. A low touch jitter impulse signal source is developed, and several common mathematical forms, generation methods and spectrum analysis of UWB signal are discussed. This paper analyzes the attenuation and propagation characteristics of Gao Si signal in geology, simulates the scattering characteristics of every order Gao Si signal in geology by using CST, and finally determines the mathematical model of impulse signal source of radar system. By analyzing the avalanche effect of the avalanche transistor, the working mechanism of the avalanche circuit and the dynamic transformation process of the operating point, a pulse source with low trigger jitter is developed based on the Marx circuit. Each index of Marx circuit is calculated theoretically, and the Marx circuit is simulated and optimized by Orcad. Driving circuit and avalanche transistor are used to design drive circuit to reduce trigger jitter and narrow pulse width is realized by constructing pulse shaping circuit of avalanche diode and filter. Selection of avalanche Crystal Triode FMMT415 and Avalanche Crystal Diode P4SMA540A Research on impulse signal source with 50 ohms load the measured peak voltage is 690V and the half peak pulse width is 500 ps, trigger jitter 32 ps. The RF front-end of time-varying attenuation receiver is developed, based on the analysis of the transmission characteristics of impulse signals in geology and the reflection characteristics of targets, the indexes of the whole petroleum drilling radar system are calculated, and the characteristics of impulse system radar are analyzed. Using MA4P7455 to develop time-varying attenuation circuit and link with low noise coefficient to increase the dynamic range and detection distance of the receiver, to allocate the index of the whole receiver reasonably, and to use ADS to optimize the whole link. The control signal of the time-varying attenuation circuit is generated by the triangulation circuit designed by the bootstrap circuit and the voltage follower. The triangulation circuit can realize the adjustable rising time at 50 ns-2 us. The RF front-end bandwidth of the whole time-varying attenuating receiver is 30 MHz-1 GHz, gain dynamic range -15dB-53dB, and the noise coefficient of the gain module is 0.82 dB, receiver noise coefficient 3.6 dB; system sensitivity -83.59 dBm.. The research of imaging algorithm is mainly based on the scattering experiment of the target. The mathematical function of the reflected signal of the target is fixed and the energy is concentrated in the range of 300 MHz-800 MHz. Based on this, the target signal can be extracted effectively by using the Fourier filter method. At the same time, using time-varying amplification, correlation function, median filtering method can effectively suppress clutter; using median filter method can also generate background signal, effectively solve the imaging problem of the target in the process of radar moving.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN958

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