With the progress of the technological development, the positioning of the Internet of Things has achieved a qualitative leap in terms of key technology, accuracy, and ease of use. On the whole, positioning can be divided into indoor positioning and outdoor positioning according to the difference in application scenarios. In view of the differences in usage scenarios, their requirements are also different, so the positioning technology used by each is also very different.
In recent years, the main technology for outdoor positioning is to use satellites or location based service
1. Satellite positioning
Now everyone knows the satellite positioning systems in the world. There are gps in the United States, Glonass in Russia, Galileo in Europe, and BDS in China. The principle of satellite positioning is to determine the position of a gps locator through a known position and a certain number of satellites. Although satellite positioning has high accuracy and wide coverage, it is limited by the environment and is not suitable for all users.
2. LBS(Location Based Service)
LBS is to obtain location information through the telecom operator's network. The positioning device will actively search for the surrounding base stations and establish contact with them. Generally, there are more than one base stations that can be searched. The distance is only different. According to the signal strength received by the device, the distance to the base station can be roughly estimated. The geographic location of the base station is unique. The distance between the three base stations and the positioning device is obtained, and the positioning can be completed according to the three-point positioning principle.
The base station positioning signal is easily affected. The accuracy is usually about 150 meters, but the positioning speed is faster. As long as there is a signal, it can be located. It is usually used to know your approximate location without GPS and Wi-Fi.
In recent years, the technology and industry of location services are developing from outdoor to indoor.
1. Wi-Fi positioning technology
In recent years, Wifi is a relatively mature and widely used technology. Because Wifi has been widely used, there is no need to set up special equipment for positioning. However, wireless network hot-spots will be affected by the surrounding environment, and the accuracy is relatively low.
2. RFID positioning
The basic principle of RFID positioning is to read the characteristic information of the target RFID tag through a set of fixed readers. The working distance of this technology is relatively short, usually only tens of meters. However, centimeter-level accurate positioning information can be obtained within a few milliseconds, with a large transmission range and low cost.
3. UWB positioning technology
In recent years, the United States, Japan and other countries have all been exploring this technology, which has a good development prospect in the field of wireless indoor positioning. UWB technology is a wireless technology with high transmission rate, low transmission power, high penetration capability, based on extremely narrow pulse, and no carrier. These advantages are the reason why it has achieved more accurate results in the field of indoor positioning.
In addition to the above, in recent years, there are dozens or even hundreds of positioning technologies. Various positioning technologies have their own advantages and disadvantages, and are suitable for their respective applications. There is no distinction between advantages and disadvantages.
