【摘要】：探地雷達（Ground Penertrating Radar，GPR）作為一種地球物理方法，廣泛應用于不同領域的地下目標無損探測。由于地下介質電磁特性的復雜程度以及目標的反射特性各不相同，為了獲得良好的探測準確性，探地雷達一般都是專機專用。為了實現青海凍土地區(qū)可燃冰的探測，要求探地雷達在該地區(qū)具有130米以上的探測深度。目前的探地雷達大多應用于幾厘米到50米的探測深度，，天線中心頻率集中在10MHz到4GHz范圍內。為了實現預期的探測深度，在增強發(fā)射雷達波在地下介質中的穿透能力的同時提高對回波信號的補償能力。本文主要對探地雷達系統的接收機部分進行設計，全文主要工作如下： 系統分析與整體設計。先對探地雷達系統的探測原理和接收機的設計需求進行研究分析，通過對不同雷達體制優(yōu)缺點的說明和對比，選擇了野外探測中移動方便顯示直觀的沖激脈沖體制雷達。在明確發(fā)射信號形式及信號衰減影響因素后，結合理論分析與經驗公式制定出設計指標，并給出了接收機硬件總體設計方案，即具有時變增益功能的內同步實時采樣探地雷達接收機。 接收機設計實現分為硬件電路、FPGA控制邏輯和上位機軟件設計三個部分。硬件電路部分，根據功能設計要求，同時考慮接收機各性能指標，分別對采樣觸發(fā)電路、時變增益放大電路、ADC采樣電路和數據傳輸電路進行詳細的設計說明。FPGA控制邏輯部分，對應各部分電路功能，分4個模塊進行基于ISE的FPGA邏輯設計。接收機與上位機采用USB總線進行數據傳輸，上位機軟件使用LabVIEW編寫，能夠完成對AD采樣數據的接收、數據顯示、波形顯示及數據存儲工作，還可以實現對增益的階梯式連續(xù)設定。 接收機功能及性能測試工作。完成了對時變增益放大、數據采集、數據傳輸功能的測試驗證；另外，還對噪聲系數、靈敏度、帶寬及動態(tài)范圍這些接收機性能評價參數進行測試，測試結果表明設計滿足功能要求，性能優(yōu)秀。相比于傳統的沖激脈沖探地雷達接收機，本文的設計具有信號能量利用率高的優(yōu)點，接收機的動態(tài)范圍得到有效的擴大，同時所采用的內同步方式能夠避免外同步方式中同步電纜移動造成的干擾。
[Abstract]:As a geophysical method, ground penetrating radar (Ground Penertrating Radar,GPR) is widely used in nondestructive detection of underground targets in different fields. Due to the complexity of electromagnetic characteristics of underground media and the reflection characteristics of targets, ground penetrating radar (GPR) is usually dedicated to special aircraft in order to obtain good detection accuracy. In order to realize the detection of flammable ice in permafrost area of Qinghai Province, the ground penetrating radar (GPR) is required to have a depth of more than 130 meters in this area. At present, ground penetrating radar (GPR) is mostly used in detection depths ranging from a few centimeters to 50 meters, and the central frequency of the antenna is concentrated in the range of 10MHz to 4GHz. In order to achieve the expected detection depth, the transmitting radar wave penetration ability in the underground medium is enhanced, and the compensation ability to the echo signal is improved at the same time. This paper mainly designs the receiver part of the ground penetrating radar system. The main work of this paper is as follows: system analysis and overall design. Firstly, the detection principle of ground penetrating radar system and the design requirement of receiver are studied and analyzed. Through the explanation and comparison of the advantages and disadvantages of different radar systems, the impulse pulse radar which is convenient to display in the field detection is selected. After defining the form of the transmitted signal and the influence factors of the signal attenuation, the design index is drawn up according to the theoretical analysis and empirical formula, and the overall design scheme of the receiver hardware is given. An internal synchronous real-time sampling ground penetrating radar (GPR) receiver with time-varying gain function is proposed. The receiver design is divided into three parts: hardware circuit, FPGA control logic and upper computer software design. In the part of hardware circuit, according to the requirement of function design and taking into account each performance index of receiver, the sampling trigger circuit and time-varying gain amplifier circuit, respectively, are taken into account. ADC sampling circuit and data transmission circuit are described in detail. FPGA control logic part, corresponding to each part of the circuit function, is divided into four modules to design the FPGA logic based on ISE. The receiver adopts USB bus to transmit the data between the receiver and the upper computer, and the software of the host computer is written with LabVIEW. The receiver can receive, display the data, display the waveform and store the data of the AD. It can also realize the step-by-step continuous setting of gain. Receiver function and performance testing work. The functions of time-varying gain amplification, data acquisition and data transmission are tested and verified. In addition, the performance evaluation parameters such as noise figure, sensitivity, bandwidth and dynamic range are tested. The test results show that the design meets the functional requirements and the performance is excellent. Compared with the traditional impulse ground penetrating radar receiver, the design of this paper has the advantages of high signal energy efficiency, and the dynamic range of the receiver has been effectively expanded. At the same time, the internal synchronization method can avoid the interference caused by the synchronous cable movement in the external synchronization mode.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TN957.5

【參考文獻】

相關期刊論文 前10條

1 周幼吾,郭東信;我國多年凍土的主要特征[J];冰川凍土;1982年01期

2 羅凡;沈金泉;嚴明明;;雷達接收機靈敏度測試方法[J];四川兵工學報;2011年05期

3 葉盛波;周斌;方廣有;;新型超寬帶探地雷達數字采樣接收機設計[J];電波科學學報;2011年04期

4 鄒海林,寧書年,林捷;小波理論在探地雷達信號處理中的應用[J];地球物理學進展;2004年02期

5 何亮;王旭東;楊放;曹華;;探地雷達測定土壤含水量的研究進展[J];地球物理學進展;2007年05期

6 李華;魯光銀;何現啟;鄧珂;;探地雷達的發(fā)展歷程及其前景探討[J];地球物理學進展;2010年04期

7 陸珉;黃春琳;粟毅;;用于高速脈沖回波采集等效采樣模塊[J];電子測量技術;2005年06期

8 吳建斌;田茂;;基于AD603的時變增益放大器的實現[J];電子測量技術;2008年04期

9 張長春;張崇超;劉小軍;;具有TVG功能的探地雷達接收機技術研究[J];電子測量技術;2012年06期

10 羅鵬,丁亞生;對數放大器的原理與應用(上)[J];電子產品世界;2005年07期

本文編號：2466943