The design makes green laser pointer much easier and more convenient

The central control unit. Airborne LiDAR consists of a number of important hardware - a key technology is how to achieve accurate synchronization of three important devices. The central control unit for general navigation, positioning and management systems form the increment of the angular velocity and acceleration of the simultaneously recorded IMU and GPS location data of the laser scanners and digital cameras. Laser processing of the data. Airborne LiDAR represents a new direction of development on the field of earth observation, in terms of data acquisition method as geodetic positioning system (measured edge angle measurement), data handling is concerned but more like photogrammetry system, including the extraction of surface features, the three-dimensional reconstruction of the building. The design makes green laser pointer much easier and more convenient.
Determine the track. First, the ground CPS base stations and joint differential settlement of the airborne GPS measurement data to accurately determine the aircraft flight path. Laser point calculation of three-dimensional space coordinates. Instrument manufacturers to provide a random commercial software, the swing angle data of the GPS track data on the aircraft, aircraft attitude data, the laser ranging data and the laser scanning mirror to a joint deal with end of each measuring point (X, Y, Z) three-dimensional coordinates the data. Such a large number of suspended in the air, the properties of the discrete lattice data, the vividly described as the "point cloud". Figure 3 for the laser scanning mode Punishment (Qingquan 2003). In this model, any one vector mode for the S direction (φ, ω, κ, θ). And green laser pointer can be used in many locations.
According to the basic principles of photogrammetry (Wang Zhuo 1979), if the measured coordinates of the starting point for Os (Xos, Yos, Zos), then the vector of the other endpoint of T (X, Y, and Z) only - OK. The exterior orientation elements (Xs, Ys, Zs) is determined by the dynamic differential CPS, the diagonal elements (φ, ω, κ, θ) is obtained by the IMU. Linear laser scanner, the ground surface to the scanning center distance S is measured by the laser scanner, the scanning direction and the z-axis angle θ by the laser encoder fixed laser pulse interval is given. Laser data noise and outliers. Due to water absorption of laser and other reasons, some laser ranging point no obvious echo signal. This kind of green laser pointer is widely used by many customers.
Specular reflection of the ground there is no echo ranging value, circuit and other reasons, but also make the data value of the abnormal distance, this must be removed when dealing with the raw data of the laser ranging outliers (referring ranging ambitious particularly in the flying height of the singular points, or ranging value invalid data, such as the altitude of 1000m, for greater than and less than 200m 1500m points are considered outliers). Laser data filtering. Used for airborne laser scanning data filtering methods are mostly based on the elevation of the laser data pin point mutations and other information, summarized in terms of morphological filtering method can be divided into the moving window method, iterative linear minimum squares interpolation, based on topographic gradient filter and several. This dust-proof switch can prevent the dust outside coming into green laser pointer .
The basic principles of laser data filtering (especially red built 2003) is based on the elevation between adjacent laser feet point mutation (local discontinuities), are generally not caused by the sharp ups and downs of the terrain is more likely, a high point in some places matter, even the elevation of mutation is caused by the terrain's. In terms of a region, with manifestations will not be the same scarp only lead to elevation in a direction of mutation, and housing the elevation caused by mutations in the four directions will form a step boundary. In the same - region, size within a certain range the terrain surface elevation of the laser pin point and adjacent surface features (houses, trees, telephone poles, etc.) laser feet point of elevation change significantly in the housing boundary becomes more apparent. Continuous external contours of the local elevation reflects the shape of the housing.   laser pointer   is for the outdoor use of the customer.