###### Abstract  
A new visible light communication (VLC) system is proposed for localization in underground mining. Existent systems, such as global positioning system (GPS) and systems based on mobile communication, are generally not useful in underground mining. The proposed system is based on a three-dimensional trilateration VLC localization scheme. This articles offers an evaluation of the proposed system in different evaluation scenarios in terms of the average localization error. The proposed algorithm localizes the source with an average localization estimation error of less than (16.4 cm), based on the source location. The average error is (3.5 cm) for subjects that are very close to the light-emitting-diode (LEDs).The obtained results show the superiority of the proposed method in comparison with traditional short range radio frequency technologies such as RFID, Wi-Fi and Zigbee, making it a feasible system for localizing objects in underground mining.  
Keywords:light emitting diode; photodetector; source localization; underground mining; visible light communication +
Footnote †: journal: Applied Soft  
Technology has provided very effective new solutions and tools for safety and accident prevention. These new tools are mainly related to telecommunication solutions. It has been proven that work environments that have accurate and instant information can save lives [6]. There are many accidents in mining due to gas explosions, cave-ins, chemical leakages, fires, and electrocution, which can lead to the loss of lives, and trapped or lost miners. In such scenarios it is essential to locate miners and provide assistance as quickly as possible. Therefore, it is very important to have proper localization systems in order to track people in underground mining environments.  
Existing positioning technologies such as the global positioning system (GPS) are not useful in indoor applications, especially in underground mining environments. This is because the signal is easily blocked by most construction materials and the mobile terminal cannot process the beacons sent from the satellites [7; 8; 9; 10; 11; 12]. Therefore, other wireless technologies such as Radio Frequency IDentification (RFID), Wireless Fidelity (Wi-Fi), and Zigbee have been preferred to provide indoor localization/positioning [5].  
In a previous work, the authors proposed a location system based on the placement of points of reference and visible light communication (VLC) technology [7]. Whereas in [10], the authors proposed a VLC system for localization in underground mining tunnels developed in conjunction with the trilateration technique in two dimensions. Whereas in this work, the system presented in [10] will be extended to a VLC three dimension trilateration localization scheme. Therefore, a smaller location estimation error is expected with the new localization scheme. The proposed system will be evaluated and compared with other existing localization systems in terms of location estimation error.  
The manuscript has the following organization. Section 2 introduces state of the art localization schemes used in underground mining environments, whereas Section 3 provides the basic concepts of VLC systems. In Section 4 the proposed method is presented in detail, whereas in Section 5, we evaluate the proposed system and compared it with other existing localization schemes in terms of the localization estimation error. Finally, conclusions are presented in Section 6.