Using unmanned aerial vehicles to create topographic maps The Institute of Geodesy and Cartography has researched and widely applied unmanned aerial vehicles (UAVs) to serve the work of making large- 

The Institute of Geodesy and Cartography has researched and widely applied unmanned aerial vehicles (UAVs) to serve the work of making large-scale topographic maps.

Unmanned aerial vehicles compared with traditional technologies have advantages such as reducing construction time, reducing labor, thereby drastically reducing production costs. Therefore, the application of unmanned aerial vehicles in the creation of large-scale topographic maps is considered to have great potential in actual production in the near future.

Stemming from that practice, scientists from the Institute of Geodesy and Cartography have successfully researched the topic: "Integrating IMU equipment and Global Positioning Satellite System (GNSS) to acquire data and use virtual reference station (VRS) technology on unmanned aerial vehicles for the creation of large-scale topographic maps”.

According to Mr. Luu Hai Au, Project Manager, this study has posed a problem to make maximum use of the external orientation parameters of the image including rotation angles and flight trajectory in establishing a topographic map of a scale. large 1:5000; 1:2000; 1:1000; 1:500 to further improve the degree of automation and minimize the workload of measuring and controlling external images.

With the great applicability of VRS technology, the implementation of a research project on integrating GNSS/IMU devices on unmanned aerial vehicles for data collection in the creation of large-scale topographic maps with the goal of combining technologies to increase the overall efficiency of the data acquisition system, thereby considering the possibility of reducing and eventually eliminating the work of measuring image control points in the process of making topographic maps. large scale figure.

In particular, the research team has built data retrieval software and image center coordinate processing software. Data from GNSS instruments and IMUs mounted on UAVs are used to improve the accuracy of the external orientation elements of the image by Kalman filter method and random error modeling.

The project's GNSS-IMU-UAV integrated device combined with virtual reference station technology and CORS stations of the Department of Surveying, Mapping and Geographic Information can completely eliminate the fixed ground base station in the field. The process of capturing flight for urban areas ensures the density of CORS stations with a distance of 50 - 70 km.

Through the experimental process, the research team found that using GNSS data combined with IMU to process the image center coordinates can reduce the number of control points to be measured by up to 80% compared to the past for different types of maps. topographic map 1:2000; 1:5000. This technology has contributed to improving the level of automation in the use of unmanned aerial vehicles in surveying and mapping terrain.

Using unmanned aerial vehicles to create topographic maps

According to Nguyen Phi Son, Director of the Institute of Geodesy and Mapping Science, UAV flight technology has many advantages such as low operating costs, allowing fast, frequent, detailed and accurate data acquisition. High and easy to create 3D data will open up many new applications in monitoring, data acquisition, and topographic mapping in Vietnam. Therefore, it is necessary to promote technical research to develop this technology in many fields. Moreover, due to its increasingly widespread application, the promulgation of administrative documents related to the application of UAV technology in the establishment of large-scale topographic maps should be of more concern.

Appreciating the research results, Director Nguyen Phi Son said that the product of the project is a system of equipment with high applicability in surveying and mapping. Therefore, in the coming time, the Institute has also proposed to the Ministry of Natural Resources and Environment to carry out a pre-production project to complete the process and improve the accuracy of mapping by using UAV flight capture technology integrated with GNSS equipment- IMU and registered intellectual property for the device's product.

Pham My Linh