global positioning system (GPS)

GPS(GlobalPositioningSystem) is a new generation of satellite navigation and positioning system, which has omni-directional and real-time three-dimensional navigation and positioning capabilities in sea, land and air. With its remarkable characteristics of all-weather, high precision, automation and high efficiency, it has won the trust of the majority of surveying and mapping workers, and has been successfully applied to geodesy, engineering survey, aerial photogrammetry, vehicle navigation and control, crustal movement monitoring, engineering deformation monitoring and other fields. GPS system has three characteristics: first, it works all over the world, and can provide users with continuous real-time three-dimensional position, three-dimensional speed and accurate time, which is not affected by the weather; Second, the positioning accuracy is high, and the positioning accuracy of a single machine is better than 10 meter. With differential positioning, the accuracy can reach centimeter level and millimeter level; Third, it has many functions and wide applications. With the deepening of people's understanding of it, GPS is not only widely used in measurement, navigation, speed measurement and time measurement, but also its application field is expanding.

GPS is mainly used to provide the spatial position of targets (including ground targets) in real time and quickly. In the agricultural land classification of Guangxi Zhuang Autonomous Region, GPS is applied to the setting and data collection of standard sample plots at all levels in the whole autonomous region. The standard sample plots are distributed in counties (cities, districts) of the autonomous region, covering many areas. In order to find out the position of the standard plot in time and accurately in the future, when setting up the standard plot, GPS satellite positioning should be carried out on the dug soil profile to determine the geographical coordinates of the profile.

The standard plot setting of agricultural land classification in Guangxi Zhuang Autonomous Region follows the principle of GPS coordinate positioning, and the standard plot setting is carried out by using the Chinese handheld positioning navigator brainstorming VistaGIS collector. The collector goes beyond the limitation of pure GPS, and makes the mobile phone truly develop into a full-featured and all-round field work tool. The main functions of setting up standard plots in Guangxi Zhuang Autonomous Region are: first, the positioning function, which uses the positioning function of global positioning system to obtain data information such as latitude, longitude, geodetic coordinates and elevation of standard plots, so as to facilitate positioning and detection on the current map; The second is the function of electronic compass. Vista's brand-new electronic compass is a combination of GPS compass and magnetic compass. Using the principle of magnetic field line navigation, it makes it easy for the operator to identify the direction, thus judging the four directions of the standard plot, which is convenient for recording data and checking the plot. In addition, it can also use the electronic compass to judge the deviation of the sun to set the appropriate profile orientation, so as to avoid the shadow on the profile and destroy the shooting effect. Third, other functions, such as barometric altimetry, unique elevation display, yaw reminder, coordinate transformation, area calculation, etc. It can also play an auxiliary role in the process of standard plot setting.