The laser distance meter is an automatic remote sensing technology that uses the laser announced by the sensor (lidar) to measure the distance between the sensor and the policy object. According to different exploration policies, this technology can be divided into two types: air exploration and ground exploration. The purpose of airborne laser ranging is to end the measurement of physical and chemical properties of the atmosphere by launching a laser beam into the air and bearing the echoes reflected by suspended particles in the air. The primary policy for ground laser ranging is to obtain surface information such as geology, topography, landform, and land use. According to the classification of sensor carrying channels, laser ranging can be divided into four categories: space-borne (satellite-mounted), air-borne (aircraft-mounted), vehicle-mounted (car-mounted), and positioning (fixed-point measurement).
Laser ranging technology began in the sixties of the twentieth century. By the seventies and eighties, laser technology has now become an important part of electronic ranging equipment. LIDAR (Light Detection And Ranging) generally refers to airborne laser ranging technology to the ground, and the Chinese term Lidar is often used to refer to LIDAR. In the United States, since the 1970s, many organizations including the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA), and the US Department of Defense Surveying and Mapping (DMA) have initially opened up LIDAR sensors. Used for ocean and topographic surveys. In Europe, research on laser ranging started almost with the United States. Unlike the United States, they are committed to opening up satellite channel laser ranging radar systems, focusing more on the development of airborne channels and LiDAR systems that match them. And achieved a considerable degree of success.
By the nineties of the last century, with the opening of the airborne GPS technology and portable computer system, the stability and accuracy of the LIDAR system has been greatly improved, and it has gradually been initially put into commercial use in Europe, and related practical research Then it opened first in Europe.
Related to other remote sensing technologies, LIDAR-related research is a very new field, whether it is in the accuracy and quality of traveling LIDAR data or the research on rich LIDAR data application technology is quite lively. Different from the remote sensing image technology, the LIDAR system can sensitively obtain the three-dimensional geographic coordinate information of the ground surface and corresponding features (trees, buildings, ground surface, etc.) on the ground. Its three-dimensional characteristics meet the current research needs of the mainstream digital earth.
With the continuous advancement of LIDAR sensors, the gradual advancement of the surface sampling point density, and the increase in the number of waves recoverable by a single laser beam, LIDAR data will provide more abundant surface and ground information. Filter, interpolate, classify, and segment the three-dimensional point set on the surface collected by LIDAR to obtain various high-precision three-dimensional digital ground models. It can also classify and identify surface features and end surface features such as trees, Three-dimensional digital reconstruction of buildings, and even the production of three-dimensional forests, three-dimensional city models, and virtual reality. Based on virtual reality, a more precise analysis of features can be carried out to estimate various parameters of forest land and its individual standing trees, and then end the management and management of precision forestry and agriculture; it can be used for urban planning, urban environment and urban climate Carry out imitative analysis, and end the evaluation and control of sound, light, and environmental pollution.