Introduction
Aeronautical surveying and mapping technology is a method of surveying and mapping the ground using aircraft in the atmosphere as a measurement carrier. The data is usually used to draw the geodetic coordinates, and the method usually used is aerial photogrammetry. Aerial photogrammetry is the process of continuously taking pictures of the ground and drawing topographical maps using aerial photography instruments on an airplane.
The development history of aerial surveying and mapping in my country
The history of photogrammetry in my country can be traced back to 1902, when Peiyang University used a photographic theodolite to survey buildings. my country's aerial surveying and mapping began in 1931. In June of the same year, the Zhejiang Provincial Water Resources Bureau's aerial survey team and the German Survey Company cooperated for the first time to take aerial photos of a section of the river channel of the Puyang River, a tributary of the Qiantang River. In August, the Kuomintang government formally established an aerial survey team. In the following years, it has surveyed and mapped important military topographic maps in some areas of our country. After the founding of the People's Republic of China in 1949, due to the needs of economic development and national defense construction, a large amount of map data was urgently needed. Therefore, aerial surveying and mapping have developed rapidly. The National Bureau of Surveying and Mapping, agriculture, water conservancy, forestry and other departments have successively started aerial surveying and mapping, which has promoted the development of these industries to varying degrees. Before the 1990s of the last century, my country used aerial photogrammetry to mainly produce topographic maps in the range of 1:25000 to 1:100,000. Provinces and cities produced topographic maps of 1:10000 and 1:5000, and cities made 1:1000 and 1:1000. 2000 topographic maps, and then use the data to form a topographic database. With the advent of digital photography in the 21st century, large-scale aerial surveys have been developed, and it has been developed to the production of electronic maps of three cities. my country has successfully built 1:1000000 and 1:250,000 spatial databases, as well as place name databases and land use databases. Provincial and municipal spatial databases of 1:10000 are being established between provinces and cities. Many cities have established 1:500～1:2000 spatial databases. Spatial database. These have laid an important foundation for building a digital country, provinces and cities. After the implementation of the western development strategy, my country started the western mapping plan, using new technology and new equipment, and rewritten the history of non-topographic data in western my country. Academician Wang Zhizhuo of the Chinese Academy of Sciences (1909-2002) is the founder of my country's photogrammetry. He calculated the differential formula of aerial photogrammetry and deduced the calculation formula for obtaining high-precision relative orientation elements of aerial photography in areas with complex terrain. In the 1960s, he proposed the use of electronic computers to analyze the encryption of aerial surveys. In the 1970s, he proposed the idea of fully digital automated mapping, which promoted the development of photogrammetry in my country. At the same time, he is also an educator. Under his leadership, my country has established a complete surveying and mapping system and trained a large number of surveying and mapping talents.
Application of new technologies in aerial surveying and mapping
The traditional aerial surveying and mapping method is to use ground control points to obtain the outer orientation element of the beam through spatial encryption. This method is too dependent on ground conditions. , There are big restrictions. At the same time, measurement workload and cost occupy a large proportion. With the needs of production development, each surveying and mapping department has successively set up an aerial survey organization to conduct aerial surveying and mapping business. The application of large-scale aerial surveying and mapping technology has been widely promoted in various surveying and mapping departments.
(1) Application of digital aerial camera DMC.
Digitalization is a sign of the information age. People's needs have changed to display the geographical information that people need in digital form. Various forms of digital surveying and mapping products just meet people's needs. Digital Mapping Camera (DMC) is a digital camera system specially used for high-precision aerial surveying and mapping. Compared with film cameras, DMC has obvious technological breakthroughs. DMC can meet the needs of small scale and high resolution and large scale. The ground resolution can reach 5cm. It can adapt to different light conditions and expose with different exposure times to ensure the quality of surveying and mapping images.
(2) Application of IMU/DGPS
GPS global positioning system has the characteristics of high precision, high efficiency, automation, etc., and is used in topographic surveying, aerial photogrammetry, resource surveying, etc. Discipline has brought a new technological revolution to the surveying and mapping industry. Inertial navigation system (INS) becomes an inertial measurement unit (IMC), which has the characteristics of independently providing high-precision navigation parameters, anti-electronic interference, and good concealment. However, the error of IMC is accumulated over time and is not suitable for long-term navigation. Because GPS and INS can complement each other, combining the two will definitely improve the overall performance of the system. The combination of these two technologies can obtain the data information of moving objects and become an integrated IMU/DGPS system. It can assist aerial surveys to reduce the layout of image control points, can obtain high-precision images that meet 1:10000 except for each photo, improve the efficiency of surveying and mapping, and can greatly reduce ground control work, which not only improves work efficiency, but also makes it difficult for peers Regional surveying and mapping work provides new technical means.
(3) LIDAR laser height measurement and scanning system.
The system is designed and installed on the aircraft in the survey and mapping of the Sino-Vietnamese border, and is widely used in areas where external control is difficult. GPS-assisted aerial triangulation technology has the advantages of low cost, high efficiency, short cycle, and reduced ground control points. It has great benefits for the surveying and mapping of difficult areas and border areas. It has a wide range of application prospects in the update of national topographic maps. .