On the study of comprehensive airborne survey system for geothermal structure

针对某地热勘查的实际应用，对提高航空电磁、磁法和红外成像勘查的探测深度、分辨能力和精度进行了基础性研究。通过直升机在地热田的实地调查，对地热田的一些问题进行了实际调查。主要研究成果如下：在航空电磁法方面，研制了接地电源航空电磁法的仪器和数据处理方法，使航空电磁法的探测深度可达几公里。为了观测地面在空中的磁响应，研制了高精度磁通门磁力仪。姿态测量设备上安装的光纤陀螺通过采集磁强计的运动信息来测量磁强计的俯仰和滚转。在野外试验测量中，利用实际装置获得了预期的数据，改进了质子磁力仪，利用航空磁测探测地热构造引起的微小磁场变化。我们还发展了测量磁场垂直梯度的方法。为了提高测量精度，我们研制了新的强质子信号激发电路。为了提高利用航空红外图像估算热辐射量的精度，我们研究了在空中获得的数据与地面数据的对比特征。同时，还提出了适用于宽数据的数据处理方法.

We conducted fundamental study for improving the depth of investigation, resolving ability and accuracy of airborne electromagnetic, magnetic and infrared image survey aiming at practical application for a geothermal survey. The study was carried out to investigate practically some issues through field survey using helicopter at some geothermal fields. The major results of each method was indicated as follows.As for the airborne electromagnetic, we developed instrument and data processing method of grounded electrical source airborne electromagnetic to increase the depth of investigation up to several kilometers. To observe magnetic response of the ground in the air, we developed high accuracy flux-gate magnetometer. The fiber optic gyros attached to the attitude measurement equipment was used to measure pitch and roll of the magnetometer, which were using collection of the motion of magnetometer. We obtained expected data using practical set up in the field test survey.We improved proton magnetometer to detect small magnetic field change due to geothermal structure with the airborne magnetic survey. We also developed the method measuring vertical gradient of the field. To increase the accuracy, we developed new circuit for exciting strong proton signal. And we contrived a circuit to adjust timing of measurement between magnetic and electromagnetic methods.To improve the accuracy of estimating heat discharge using airborne infrared image, we investigated characteristics of the data obtained in the air in comparison with surface data. We also developed data processing method for wide data.