The purpose of establishing the positioning system of stack reclaimer in coal yard: by positioning the position of stack reclaimer in the track, and positioning the position of the coal reclaiming area of stack reclaimer, so as to obtain the coal reclaiming position information of each area in real time, and calculate the amount of coal delivered to the raw coal bin and the amount of coal stored in different coal types in each area. With accurate position information of stacker reclaimer, it also enables anti-collision protection of stacker reclaimer to avoid production safety accidents.
At present, most of the stacker reclaimer position detection is the human eye positioning, laser displacement sensor, walking limit switch, RFID way, the addition of a scale ruler to accurately determine the position of the system detection technology.

All of the above location detection methods have certain defects, specifically：

a.Human eye positioning is subject to eye health and mental state, with relatively high environmental impact and long operating hours.

b.The laser displacement sensor will lose its function in unclean environment, the track settlement causes the vehicle to travel jitter will make the reflector target position inaccurate, also will lead to position detection inaccuracy.

c. Travel limit switches have a blind spot for continuity position detection due to their point positioning.

d. RFID method is a wireless point positioning, there is the phenomenon of missed reading, the delay is large.

e. Adding the scale bar method is costly, complicated to install, and easy to wear in the harsh field environment.

1. Enclosed coal yard internal stacker reclaimer positioning solution

UWB positioning technology is the most accurate and mature among various indoor positioning technologies, and the general accuracy of UWB wireless positioning is 10cm, and the highest accuracy can be within 5cm.

UWB wireless positioning principle: the location of the wireless base station is known, the tag sends out wireless pulse signals, and the distance from the tag to each base station is obtained according to the time the tag arrives at each base station multiplied by the speed of light.

By installing multiple indoor positioning base stations on the top of each enclosed coal yard and on the horse path, and installing positioning terminals on the stack reclaimers, the precise positioning of the stack reclaimers is realized. Through the precise positioning information of the stacker reclaimer positioning system, it realizes the standardized management of stacker reclaimer coal reclaiming according to the plan, and realizes the automatic sound and light alarm of the system to prompt the stacker reclaimer operator when the coal reclaiming area does not match the planned coal reclaiming area location. Real-time monitoring of bucket wheel machine position information to reduce the risk of stacker reclaimer impact.

2. Open pit stacker reclaimer positioning solutions
The open-pit coal pile reclaimers mainly use differential base station positioning technology, using real-time dynamic positioning (RTK) technology based on carrier phase observations, which can provide real-time 3D positioning results of the station in the specified coordinate system with centimeter-level accuracy. In the RTK operation mode, the reference station transmits its observations to the mobile station together with the station coordinates through the data chain. The mobile station not only receives data from the reference station through the data chain, but also collects BeiDou/GPS observation data and composes differential observation values in the system for real-time processing, while giving centimeter-level positioning results.