超深定向钻孔雷达采控系统设计及测试研究

Data acquisition and control system design and tests of borehole ground penetrating radar for ultra-deep orientated detection

钻孔雷达有效解决了探地雷达探测深度和精度相矛盾的问题。为实现钻孔雷达对异常体的精细化、定向探测,文中对超深定向钻孔雷达的数据采集与控制系统进行设计。首先设计了钻孔雷达定向探测功能模块,由陀螺仪、单片机和步进电机组成闭环控制单元,PID控制算法依据实时角度与设定角度偏差确定电机控制参数,再由电机驱动“双套管”机械结构完成定向;接着围绕STM32F407主控设计了雷达收发脉冲控制电路、雷达反射波信号采集电路等;最后测试分析了系统收发机触发脉冲等关键信号,并利用定向钻孔雷达开展了实地模型和煤矿掌子面探测。结果表明,系统满足定向钻孔雷达功能需求,关键信号实测评价指标与理论值最大偏差仅9.8%;定向钻孔雷达可精确测得目标体的方位、深度等信息,可准确定位煤岩分界面。

Borehole ground penetrating radar(BGPR) can effectively solve the contradiction between detection depth and accuracy of traditional ground penetrating radar. In order to realize orientated detection and accurate location of geologic anomalous body with BGPR, the data acquisition and control system of BGPR for ultra-deep orientated detection is designed in this paper. Firstly, the orientated detection functional module including control unit, control algorithm and mechanical structure is researched. The closed-loop control unit is composed with gyroscope, one-chip computer and stepper motor. The control algorithm is PID, which can determine the motor control parameters according to the deviation between the real-time angle acquired from gyroscope and the setting detection angle. Then the motor drives the “double tubes” mechanical structure to finally realize orientated detection. Secondly, the radar transmit-receive pulse control circuit, radar reflected wave signal acquisition circuit and communication circuit are designed, whose main control chip is STM32 F407. Finally, the key signals of the above system such as the transmit and receive trigger pulses are tested and analyzed, and the field model and coal mine working face detection are carried out using the orientated detection BGPR, which is equipped with the above-designed system. The signal test results and detection results show that the novel system can fully meet the functional requirements of orientated detection BGPR, and the maximum deviation between the measured and theoretical values of key signal evaluation indexes is only 9.8%. In addition, the orientated detection BGPR can accurately detect the positional information such as the depth and orientation of the target, and can also accurately locate the interface between coal seam and rock stratum.