Application of laser and radar in laser rangefinder
The laser distance measuring instrument network is an active remote sensing technology that measures the distance between the sensor and the target through the laser emitted by the sensor (lidar). This technology can be divided into two categories: air detection and ground detection according to the different detection targets. The purpose of airborne laser ranging is to complete the determination of atmospheric physical and chemical properties by emitting a laser beam into the air and receiving echoes reflected by suspended particles in the air. The main goal of ground laser ranging is to obtain surface information such as geology, topography, landform and land use status. According to the classification of sensor-mounted platforms, laser ranging can be divided into four categories: spaceborne (satellite-mounted), airborne (aircraft-mounted), vehicle-mounted (car-mounted) and positioning (fixed-point measurement).
Laser ranging technology began in the 1960s, and by the 1970s and 1980s, laser technology had become an important part of electronic ranging equipment. LIDAR (Light Detection And Ranging) usually refers to the airborne ground-to-ground laser ranging technology, and the Chinese term commonly used lidar to refer to LIDAR. In the United States, since the 1970s, a number of agencies, including NASA, the National Oceanic and Atmospheric Administration (NOAA), and the Department of Defense Mapping (DMA), have begun to develop LIDAR-like sensors. For ocean and terrain measurements. In Europe, research on laser ranging started almost at the same time as the United States. Unlike the United States, they are committed to the development of satellite platform laser ranging radar systems, and more focused on the development of airborne platforms and matching lidar systems. and achieved considerable success.
By the 1990s, with the development of airborne GPS technology and portable computer systems, the stability and speed of the LIDAR system have been greatly improved, and it has gradually begun to be commercialized in Europe. Immediately expand in Europe.
Compared with other remote sensing technologies, the related research of LIDAR is a very new field, and the research on improving the accuracy and quality of LIDAR data and enriching the application technology of LIDAR data is quite active. Different from the remote sensing image technology, the LIDAR system can quickly obtain the three-dimensional geographic coordinate information of the surface and the corresponding objects (trees, buildings, ground, etc.) on the surface, and its three-dimensional characteristics meet the mainstream research needs of today's digital earth.
With the continuous advancement of LIDAR sensors, the gradual increase in the density of surface sampling points, and the increase in the number of recoverable waves of a single laser beam, LIDAR data will provide more abundant surface and feature information. By filtering, interpolating, classifying, and segmenting the 3D surface point sets collected by LIDAR, various high-precision 3D digital ground models can be obtained, and surface objects can also be classified and identified, and surface objects such as trees, trees, 3D digital reconstruction of buildings, etc., and even drawing 3D forest, 3D city models, and constructing virtual reality. On the basis of virtual reality, more detailed ground object analysis can be carried out to estimate the parameters of the forest land and its individual standing trees, so as to realize the operation and management of fine forestry and agriculture; it can be used for urban planning, urban environment and urban climate. Carry out simulation analysis to realize the evaluation and control of sound, light and environmental pollution.
