GPS is the Global Positioning System, a satellite navigation and positioning system developed by the U.S. Using this system, users can realize all-weather, continuous, real-time three-dimensional navigation and positioning and speed measurement on a global scale.GPS positioning system is the world's most widely used positioning system, but its use is limited to the outdoors, in the indoors can not be used properly.
1, GPS can not be 100% positioning, indoor positioning is more inaccurate. GPS will also be affected by many aspects, including buildings, viaducts, airwaves, etc., in general, GPS in the more open places the more accurate positioning.
2. It is affected by the state of the satellites in the sky. The use of GPS do not use once or twice or a day or two to decide the GPS is good or bad, because the sky satellite status is different every day, maybe the same place, the morning signal is full, but the night can not be located. Even a few days in a row can not locate the situation occurs.
3, indoor can not be positioned. As GPS receives signals directly from satellites, you can't use GPS indoors.
4, GPS instruments are different, the effect may be a world of difference.
Today's indoor also have a professional indoor positioning system, the use of more of these:
1. Bluetooth indoor positioning
Bluetooth communication is a short-range, low-power wireless transmission technology, in the indoor installation of the appropriate Bluetooth LAN access point, the network will be configured as a multi-user based on the basic network connection mode, and to ensure that the Bluetooth LAN access point is always the main device of this micro-network. the master device of this micro-network. This way the user's location information can be obtained by detecting the signal strength.
Bluetooth positioning is mainly used for small area positioning, such as a single-story hall or warehouse. For holding the integrated Bluetooth function mobile terminal equipment, as long as the Bluetooth function of the equipment is turned on, the Bluetooth indoor positioning system will be able to judge its position. However, for complex spatial environments, the stability of the Bluetooth positioning system is slightly poorer, and it is greatly interfered by noise signals.
2. Wi-Fi indoor positioning
Through the wireless access point (including wireless routers) composed of wireless local area network (WLAN), can realize the complex environment of positioning, monitoring and tracking tasks. It takes the location information of the network nodes (wireless access points) as the basis and premise, and uses a combination of empirical testing and signal propagation modeling to locate the position of the mobile devices that have been accessed, with a maximum accuracy of about 1 meter to 20 meters. If the location measurement is based only on the currently connected Wi-Fi access point, instead of referring to the signal strength composite map of the surrounding Wi-Fi, the Wi-Fi location is prone to errors (e.g., locating the wrong floor).
Additionally, Wi-Fi access points usually only cover a radius of about 90 meters, and are susceptible to interference from other signals, which affects their accuracy, and the locator's energy consumption is high.
3. Ultra-broadband indoor positioning personnel management system, which is an emerging wireless technology in recent years, this positioning system, fast transmission speed, low transmit power, penetration is also very strong, anti-jamming is also very strong, and you can get accurate results, the disadvantage is that, now the cost is high, so as long as the solution to the problem of the cost, then the ultra-broadband positioning technology, in the field of wireless indoor positioning will have a very good prospect.