UAV applications: scientific exploration

UAV applications: scientific exploration

I. Background

In recent years, international aviation geophysical exploration flight platforms have developed from traditional manned aircraft to drones. At the same time, whether the performance of aerial object detection equipment meets the working requirements is also an important factor limiting the use of UAVs in geophysical exploration. If the performance parameters of the detection equipment are up to standard, the application of UAVs in geophysical exploration will have a very broad application prospect.

1. Main applications abroad

UAV technology has been widely used in various fields in geophysical exploration abroad and has achieved good results, which has greatly improved the quality of scientific research. These have a very good reference for China's related technology applications.

Magsurvey Limited in the United Kingdom provides drone detection of the Earth's magnetic field. The literature describes the use of small fixed-wing drones equipped with magnetometers to detect oil, gas, and mineral resources. Point out the reasons for using small fixed-wing drones as mobile platforms:

① Mission load-cesium light pump magnetometer with high accuracy and lightweight (less than 1kg), the small unmanned aerial vehicle can fully carry;

② Small UAVs can fly near the ground (flying height less than 20m), and can obtain more accurate detection data;

③The drone is equipped with advanced GPS / INS, altimeter, and precise control flight control system, which can ensure the drone to fly accurately according to the planned flight path;

④ The detection is generally performed in the dark environment at night to reduce the interference of solar activity and environmental noise on the detection; ⑤ Compared with manned aircraft, small UAVs will use fewer and lighter non-metal composite materials on the body material. In this way, the electromagnetic and gravitational fields generated by the body have less influence on the detection instrument.

In 2004, the Canadian Fugro company invested in the development of Geoanger, a drone aeromagnetic system for resource detection, for oil and mineral exploration in coastal and remote areas. The drone system has recently entered the test flight phase. The drone has a wingspan of 3m, a fuselage weight of 15kg, and a cruising speed of 100km / h, and the endurance time can exceed 15h. The drone is equipped with a cesium vapor magnetometer and a flight compensation device, which is used to reduce the interference of the movement of the fuselage on the detection data.

2. Main domestic applications

In China, the application of unmanned aerial vehicles in geophysical exploration started late and is still in the research and development stage, which is far from the international level. With the country's emphasis on energy strategy, the exploration of its own energy and energy reserves have been put on the agenda. Therefore, China is continuously increasing its efforts to support the application of UAV technology in resource detection, and has made great progress. In 2010, Academician He Jishan of Central South University presided over the completion of a small unmanned helicopter prospecting technology, which provided technical support for China to compensate for the source of iron ore. The drone is equipped with a proton precession magnetometer, which can have a good detection effect on iron ore below the ground. Because the small unmanned helicopter is very suitable for flying in complicated mountain terrain and has the characteristics of fast detection speed, high detection efficiency, and no casualties, it is very suitable for mountain prospecting. In 2011, the National Earth Depth Exploration Special Project Sino-2009-03 Aeroplane Magnetic Detection System Development Subproject conducted a test flight of a fixed-wing UAV equipped with an aviation magnetometer and obtained good test data. The project is committed to the development of aeromagnetic detection systems for high- and low-altitude fixed-wing UAVs, focusing on key technologies such as core sensors, fixed-wing low-magnetic UAVs, magnetic interference compensation, and system integration. The project is in the research and development and research phase. I believe that China's first fixed-wing low-magnetic drone aeromagnetic detection system will soon be launched, providing a safe and efficient detection tool for China's deep scientific exploration and mineral resource exploration.

Introduction

As a low-cost, flexible operation, and non-personnel injury airborne mobile detection platform, UAVs meet the needs of high-efficiency resource exploration, and use UAV technology for geophysical exploration. In geophysical exploration, UAVs are an important means for collecting space bitfield data with high efficiency and high accuracy under complex terrain conditions and are used to reveal the distribution of field sources in underground bitfields. By carrying different mission loads (magnetometer, gravimeter, gravity gradient instrument, radioactivity detector, an electromagnetic coil, etc.), the UAV can realize the geophysical detection application of the UAV's aeromagnetic, aeronautical weight, aeronautical amplifier, and aeronautical electromagnetic. At present, UAV geophysical detection technology belongs to international cutting-edge technologies and research hotspots, and only a few developed countries, such as the United States, Britain, Israel, Canada, Germany, and France, have mastered its core technology.

Application method

UAVs can be divided into fixed-wing drones, rotary-wing drones, and unmanned airships according to the way the body generates lift. Each of these three types of drones has its advantages and disadvantages:

① Fixed-wing UAVs have the advantages of fast flight speed and good flight stability, so they are generally suitable for earth resource exploration in flat areas. Due to the stall problem of fixed-wing UAVs, their minimum flight speed is generally quite high. Large, unsuitable for detection needs that require flight at very low speeds.

② Rotary drone mainly refers to the unmanned helicopter. It can fly at very slow speeds, and even hover in the air. Therefore, rotary drones are generally suitable for occasions with complicated terrain, slow flight speed, and flight following the terrain. The disadvantage is that the battery life is short, the fuselage vibration is large, and the seismic performance of the detection instrument is higher.

③The unmanned airship uses its own buoyancy, it needs a small power output to hover and fly in the air, and it can fly very smoothly when the ambient wind speed is low; due to the low energy consumption, the unmanned airship's endurance The time is generally long; it is suitable for geophysical exploration with long detection time and slow flight speed; the disadvantage is that the volume is large, it is greatly affected by the ambient airflow, and the wind resistance is poor; due to its large inertia, the response time after control is relatively long.

In the actual exploration process, depending on the exploration environment and technical indicators, selecting an appropriate drone platform to complete the task can better ensure the complete quality of the exploration task and improve the detection efficiency.

Fourth, existing problems

1.The drone itself

The drone itself is a very complicated system. It integrates materials, flight control systems, data links, and power systems. Any problem in any part will affect the application of the drone in geophysical exploration. How to improve the drone's endurance time, intelligent flight control and mission management, mission payload weight, and flight adaptability in harsh environments is an important factor for whether drones can be widely used in geophysical exploration.

2.Earth exploration equipment

The drone is just an aerial mobile platform, and the geophysical detection equipment it carries is the core tool for geophysical exploration. Only when the performance indicators of the geophysical detection equipment pass the standards, will we be able to obtain the real data of the geophysical field. However, in the research and development of geophysical exploration equipment, there is still a large gap between China and foreign advanced levels, so the research and development of geophysical exploration equipment have a long way to go.

3. Coupling factors

After the performance parameters of the ball physical detection equipment meet the detection needs, another issue is very important, whether the detection equipment can work stably in the drone flying environment. That is, the electric system, power system of the UAV platform itself, the electrostatic field generated by the friction between the airframe and the air in flight, and the vibration of the fuselage caused by air turbulence, etc., all these factors will adversely affect the detection equipment. Although the airborne stabilization platform can effectively reduce the impact of the fuselage vibration on the detection equipment, how to reduce or eliminate the interference of the electrostatic field, electromagnetic field and gravity field applied by the body is a problem to be solved.