Recently, a coal mine drone has attracted attention. Can drones be used in coal mines? If it can, how to realize real-time positioning of UAV (fixed-point hover)? This article about the technology used to locate people in coal mines, which is indoor positioning technology.
The current mainstream indoor positioning technologies include:
1. WiFi indoor positioning technology
There are generally two types of WiFi indoor positioning technology: one is to complete the triangular positioning according to the wireless signal strength of the mobile terminal and the three wireless network connection points according to the differential algorithm. The other is to record the signal strength of a large number of location points in advance, and determine the location based on the signal strength of the newly added device compared to a database with a large amount of data.
2. Ultra-wideband UWB indoor positioning technology
Due to the stronger anti-interference ability of UWB (ultra-wideband) pulse signals, UWB (ultra-wideband) pulse signals are used to analyze the position of the tags by multiple sensors using TDOA and AOA positioning algorithms, positioning accuracy Up to sub-meter level. The key application areas are: prison inmate positioning, factory worker equipment positioning, nursing home elderly positioning, tunnel personnel positioning, construction site personnel positioning, etc.
3. Infrared indoor positioning technology
There are two types of infrared indoor positioning. The first is that the target to be located uses infrared IR marks as the moving point, emits modulated infrared rays, and completes positioning according to the optical sensor installed indoors. The second is to cover the space to be measured according to the infrared network between multiple pairs of transmitters and receivers, and directly locate the moving target.
In addition, there are ultrasonic indoor positioning technology, RFID indoor positioning technology, and Bluetooth indoor positioning technology.
In terms of positioning principle, indoor positioning technology is the same as GPS positioning, and it also needs to rely on the corresponding carrier to play the role of “middleman”. GPS uses electromagnetic waves, ultra-wideband UWB indoor positioning technology uses UWB (ultra-wideband) pulse signals, infrared positioning technology uses infrared light, and ultrasonic positioning technology uses ultrasound. Then all need to use the receiving device to parse the information carried by the “middleman” and complete the solution positioning according to a special algorithm. This is the same place for indoor positioning technology and GPS positioning, and it is also a reference for GPS technology to the former.
