Outdoor positioning is generally divided into:
The LBS base station locates 20-200 meters in the urban area and 1000-2000 meters in the suburb. The rest are basically satellite positioning. The global satellite positioning systems include China Beidou, Galileo of the European Union, GPS of the United States, Gronas of Russia, and some regional ones, such as India Regional Navigation Satellite System (IRNSS) and Japan Quasi Zenith Satellite System.
In fact, the most common one is A-GPS used on mobile phones. The actual error accuracy of Beidou+GPS dual-mode or multi-mode on the market is still 5-10 meters. A-GPS performs auxiliary positioning on the basis of GPS receiving positioning signals through satellites, combined with the positioning information of network stations provided by operators. On the one hand, GPS terminals obtain positioning information from satellites, On the other hand, it also depends on the terminal to download auxiliary location information through the network. The combination of the two can complete the location, which is why the mobile phone cannot locate when there is no signal.
Then there is Beidou RTK high-precision positioning. The carrier phase difference technology, also known as differential positioning, is a technology that assists the global navigation satellite system. Simply put, the error of the obtained positioning information is large, so a ground base station is set up. The ground base station obtains satellite positioning and compares it with the real position, calculates the positioning error, and sends the current error to the mobile terminal through the network. The mobile terminal will use this error to obtain high-precision positioning information through calculation. Therefore, the RTK high-precision terminal needs to be networked, In addition, you need to purchase the differential account of the operator, so that the accuracy can reach the sub meter level of less than 1 meter, as well as the centimeter level; If you don't want to pay the differential account fee annually, you can set up a ground station in a fixed area, or you can choose our self-developed high-precision module. The four arm spiral antenna with better antenna use can also reach the sub meter level.
In addition, PPK technology, namely dynamic post-processing technology, is a supplement to RTK technology, which is generally used on UAVs to adjust flight attitude.
There is also a kind of positioning without network. That is our Beidou positioning in China. The first and second generation Beidou cards have been suspended. Now the third generation Beidou is officially operating. The terminal with the third generation Beidou chip can realize positioning and short message in the environment without network.