In recent years, with the development and application of the geographic information industry, remote sensing, as the front end of the geographic information industry, has also received much attention. Traditional geospatial data acquisition methods are facing the challenges of modern technology and equipment. Advances in remote sensing technology, especially the large number of high-resolution satellite imagery applications and the development of aerial remote sensing, have injected fresh blood into the data acquisition methods.
The advantages of satellite remote sensing images need not be repeated, and they have been welcomed by the masses as a supplement to vector maps. However, as a professional geographic information application, its insufficient data acquisition ability, poor current situation, and slow return visits are its flaws. Compared with satellite remote sensing, traditional large aircraft aerial photography is more flexible and the image quality is higher, but the process of aircraft leasing, airport management, and airspace application is too complicated, and the requirements for clouds are relatively high. At the same time, with the development of communication technology, sensors, and other technologies, surveying and mapping drones have emerged as a low-cost, high-precision, easy-to-use remote sensing image acquisition equipment, and have been used in traditional surveying and mapping, digital city construction, geographical conditions Good results have been achieved in monitoring and emergency response.
UAV mapping
Since the 1980s, unmanned aerial vehicles have been used in surveying and mapping projects abroad. Before the global positioning system was opened to civilian use, unmanned aerial vehicles could only perform aerial photography operations through simple remote control operations. There are many types of drones, including drones and airboats.
Airboats have been around for more than 200 years and have been transformed from hot air balloons. Initially, airboats were mainly used for military strikes and later used for high-altitude reconnaissance. As a low-cost, convenient-to-operate aircraft, many surveying and mapping units have some new-type surveying and mapping airboats. But the shortcomings of the airboat are very obvious: it takes a long time to prepare for take-off because a large amount of helium needs to be injected before the flight; too much time is wasted due to the need to overcome the air resistance during take-off and landing; It is difficult to run stably in harsh conditions.
Compared with empty boats, surveying and mapping drones are also less expensive and highly operable. They can take off and land anytime, anywhere, do not require much preparation time, and can adapt to different terrain and weather conditions. An excellent means of aerial photography, and has become more and more popular in surveying and mapping units.
Mapping drone advantages
Drones are equipped with sensors for shooting aerial remote sensing images. On the one hand, low-altitude remote sensing is widely recognized and needs to be robust; on the other hand, compared with other remote sensing data acquisition methods, mapping drones have irreplaceable advantages:
Cost-effective
At present, the price of domestic surveying and mapping drones on the market is between hundreds of thousands to hundreds of thousands, and the number of reusable times is large. It is not easy to be damaged except for major accidents, and there are no other additional use costs. In areas where the natural environment is relatively harsh, such as plateaus, offshore, etc., even if there is an accident, there will not be much less. Images with a resolution of up to 0.05 meters are more accurate than satellite images.
Easy to carry and transport
Fixed-wing surveying and mapping UAV wingspan generally does not exceed 3 meters and can be easily disassembled. During the execution of the project, the operator and all equipment can be transported to the destination at the same time as long as the disassembled drone equipment is placed in an ordinary pickup truck. After arriving at the scene, the drone assembly and commissioning can be completed within half an hour.
No venue requirements
The traditional surveying and mapping drone take-off method are generally skid-up, which requires a relatively horizontal runway of 30 meters to 50 meters to take off. With the introduction of emerging equipment, the venue is no longer an obstacle to drone take-off and landing. In addition to sliding up, common UAVs can take off by catapult or hand throw, and they can parachute directly when landing, which is extremely convenient for field operations. The ejection frame can be fixed on the roof of the work vehicle, or it can be spread on the ground after deployment.
Maneuverable
The mapping drone can determine the flying height according to the required image resolution. In most cases, the flying height is generally 100 meters to 1000 meters. Most of the cameras used in mapping drones use fixed-focus lenses. The difference in flying height directly affects the resolution of the final image. By designing the route and determining the flight height before the flight, you can obtain the ideal data.
Little affected by weather
In traditional aerial photography, the biggest concern for large aircraft aerial photography is the unsatisfactory weather conditions. Once cloudy weather occurs, it will seriously affect the imaging effect. But mapping the drone's flying height determines that the cloud thickness will not affect the imaging, especially when acquiring high-resolution images and flying at low altitudes.
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