What are the GPS positioning modes and methods?

GPS positioning is the most common. Good signal, high positioning accuracy and wide application range. Almost all devices that need positioning will give priority to GPS positioning. The disadvantage is that the signal can't penetrate the mixture of metal and reinforced concrete, so it can't be used indoors, such as underground parking lots, under Gao Qiao and under dense buildings. Moreover, when GPS first started positioning, the speed of searching for stars was slow, which took about 2 to 3 minutes, but now this defect has been well solved. Many GPS positioning devices have AGPS or EPO-assisted positioning function to help locate the position quickly when searching for stars, which usually takes only a few seconds. With the help of AGPS or EPO, the cold start speed of GPS module like SKYLAB can be controlled at about 23s, the hot start time is 2-3s, and the hot start time is less than1s..

Beidou positioning, as we all know, Beidou is a satellite positioning method that can compete with GPS positioning. The positioning principle is the same as GPS, and the current position is determined according to the satellites in the sky. Although the principle is the same, there is still a certain gap between the positioning accuracy and the application scope. Now it is mainly used in the military, and the civil scope is still being vigorously promoted. The positioning accuracy of civil sights ranges from several meters to tens of meters. The positioning chip price of Beidou module is higher than that of GPS module. At present, the GPS satellite positioning system covers the whole world, which can ensure that 6-9 satellites can be observed at any time on the earth (in fact, up to 65,438 satellites can be observed). The current Beidou-3 navigation system can provide high-precision and high-reliability positioning, navigation and timing services for all kinds of users around the world, and has a unique short message communication function. Compared with Beidou-2 satellite system, the coverage area has been expanded from regional coverage to global coverage, and the performance and system reliability have been greatly improved. At present, the independent positioning accuracy of the Beidou module (multimode) of SKYLAB is 3M, and the positioning accuracy based on the satellite-based augmentation system can reach 2.5M.

Base station positioning, base station positioning is also a very common positioning method. It is a base station established by three major communication operators, so its advantages and disadvantages are obvious. There are many base stations nearby, and the positioning is accurate. If there are few or no sites, the positioning error is large or it is impossible to locate. Generally speaking, regardless of the number of base stations, the positioning error of base stations is about tens of meters and the error is hundreds of meters.

WiFi positioning, WiFi positioning is actually one of the indoor positioning methods, but with the wide coverage of WiFi outdoors, it has gradually been well applied in outdoor positioning technology. I won't go into details about the principle of wifi positioning here. Technical things are actually more difficult to understand. As long as we know, generally speaking, the location of wifi hotspots (that is, AP or wireless routers) is fixed. As long as the hot spot is electrified, no matter how encrypted, it will definitely send a signal to the surrounding area. As long as the device can scan wifi, the positioning end can send the detected hotspot information to the server without connecting wifi. The accuracy of WiFi positioning is also very high. The disadvantage is that the client must be able to access the Internet and there must be a WiFi hotspot nearby. Without big cities, this function is difficult to use.

Bluetooth Beacon indoor positioning, simply put, Beacon is a small information base station, which can be used for indoor navigation, mobile payment, in-store shopping guide, crowd analysis, item tracking and other activities related to people's indoor mobility. What Beacon technology does is to intelligently capture information through Bluetooth and push it to mobile devices within communication coverage.

1. These Bluetooth beacon base stations continuously send beacon broadcast messages (messages contain transmission power).

2. After receiving the beacon broadcast message, the terminal equipment equipped with Bluetooth 4.0 module measures the received power and brings it into the function of power attenuation and distance to calculate the distance from the beacon base station.

3. Using the distance from multiple beacon base stations, the function of multi-point positioning can be realized.

Fingerprint positioning technology, in indoor environment, especially in large buildings, radio waves will be absorbed by propagation loss, reflection, refraction, diffraction, multipath propagation and other means every time they touch the surface of obstacles.

Although the indoor environment is complex, the basic pattern remains unchanged and the facilities will not be greatly moved. Therefore, as long as the signal source remains unchanged, the characteristics of wireless signals (signal number, intensity, etc.). ) formed in a specific location will show a high degree of particularity.

If this feature is associated with the coordinates of the location, then the signal feature can represent the location of the point, which is a necessary condition for the establishment of fingerprint positioning technology.