What field does gps belong to?

GPS is the global positioning system (GPS). It is a satellite network consisting of 24 artificial satellites which are more than 20,000 kilometers away from the Earth and are basically evenly distributed on six orbital planes, and constantly transmits positioning signals to the Earth. Users receive three or more GPS satellite signals through GPS receiving equipment (receivers), and then obtain information such as the user's position and speed through signal processing, so as to achieve accurate positioning of the target. GPS global positioning system can be applied to a set of software and hardware systems for vehicle monitoring, dispatching and alarm. The system installs a set of on-board GPS terminals with GPS positioning function and communication (usually GSM short message, GPRS or CDMA 1X) function on buses, trucks, public security, escort, dangerous goods transportation and other vehicles, and sends short messages or network (GPRS or CDMA) signals to the GPS center platform through the on-board mobile phone card. The GPS central platform stores and processes the received signals and sends them to the GPS dispatching computer. The GPS dispatching computer is connected to the GPS central platform through GPS dispatching software or the Internet, so as to check the running situation and trajectory of vehicles, receive alarm signals, and monitor, dispatch and manage vehicles. The popularization and application of vehicle-mounted GPS system has greatly improved the scientific and technological management level of transportation enterprises. The realization principle of GPS positioning system is analyzed in detail: GPS (global positioning system). The whole system is divided into the following three parts: the space satellite part consists of 24 polar orbiting satellites, which are divided into six orbits, with an altitude of about 20,200 kilometers and an orbit around the earth of about 65,438+02 hours. Each satellite continuously emits radio waves carrying satellite orbit data and time, and provides various receivers on the earth. The ground control part is to track and control the operation of the above-mentioned satellites. The main job of the ground control station is to correct and maintain the parameter data that each satellite can maintain normal operation, so as to ensure that each satellite can provide correct information for the user receiver to receive. User receiver tracks all GPS satellites? [6] How about the post office? The coordinates of position, moving speed and time, GARMIN GPS belongs to this part. What we ordinary people can have and apply is the third part. The calculation principle is as follows: each space satellite has a coordinate value to indicate its position (known value) at any time when it is running, but the position coordinate of the receiver is unknown. In the process of transmission, the time required for the information of space satellite can be calculated by comparing the satellite clock with the clock in the receiver, and the distance between the space satellite and the user receiver can be calculated by multiplying this time difference by the transmission speed of radio waves (generally defined as the speed of light), so that it can be listed according to the triangular vector relationship. Usually, the receiver we use calculates the coordinate data of the position according to the above principle. Whenever we receive a satellite, we can list a related equation. Therefore, after receiving at least three satellites, we can calculate the plane coordinates (latitude and longitude). After receiving four satellites, we can add elevation values. More than five satellites can improve accuracy. This is the basic positioning principle of GPS. Generally speaking, the coordinate data of the user's receiver is up-to-date every second, that is, the receiver will automatically and continuously receive satellite information and calculate the coordinate data of its position in real time, so the user does not have to worry about whether the data displayed by the receiver is too old or inaccurate. Because the satellite is in a fairly high orbit, its transmitted signal is quite weak, so it can't be used indoors or receive signals like ordinary communication radios or mobile phones. Pay attention to the following items when using: 1. It should be used outdoors and in places where the sky is open, otherwise, if most satellite signals are blocked by buildings, metal covers, dense forests and so on. The receiver will not be able to obtain enough satellite information to calculate its position coordinates. 2. Please don't use it in the strong radio wave environment of about 1.57GHz, so the satellite signal can be easily covered by the environment, and the receiver can't get enough satellite information to calculate the position coordinates, especially under the high-voltage tower. 3. The elevation calculated by GPS alone is not what we usually call altitude and flight altitude measured by barometer, because the sea level datum points used are different, so please pay attention to this when using it. The basic application of GPS is navigation and positioning. The positioning aspect has been described above, and the navigation aspect is calculated by using the obtained positioning data. Any time coordinate data calculated by the receiver is called waypoint in GPS, which means that each waypoint represents a coordinate value. For more important waypoints, we can store them in the receiver and name them so that we can identify them. Because any position on the earth's surface is represented by different coordinate values, as long as the coordinate data of two different waypoints are known, the receiver can immediately calculate the linear distance, relative azimuth and sailing speed between the two waypoints, which is the source of navigation data of GPS receiver. For example, at present, we are in Nansha Port of Guangzhou and want to go south. The first destination is Humen and the second destination is Hong Kong. From the starting point to the end point, each stop is a waypoint, and the journey between waypoints is called LEG, which passes through Ryukyu and other points in turn from the starting point to the end point. The whole journey is called a route or route. The icon is as follows: (waypoint) flight segment (waypoint) flight segment (waypoint) Guangzhou Nansha Port → Humen → Hong Kong The whole process is called: route. As long as we input the coordinate data of each point (using maps or inquiring related data) into the GPS receiver in advance, we can create a lot of waypoint data, call it up when needed, and use the navigation function of the GPS receiver to navigate between segments. In navigation, in order to prevent our traveling direction from deviating too much, some GPS provide the function of setting the route width -CDI. As long as we deviate from the route width limit we set, GPS will automatically remind us, which is the function of CDI. Therefore, in order to use GPS for navigation, the most basic thing is to first establish the data of waypoints and then store them in the receiver, so whether you want to navigate between waypoints or edit the route, you can directly use the waypoint data in the memory. It can also be said that "waypoint" is the most basic data needed for the navigation function of GPS receiver.