UWB high-precision positioning helps safety production management in the coal mine field

The Internet of Things technology has been developed for nearly 10 years, and its application prospects are very broad. Various technical means have already "flexed their muscles" in hazardous situation detection applications in many industries.

When it comes to hazard monitoring, location information technology is of course inseparable. In outdoor environments, satellite positioning methods such as Beidou, GPS, and GLONASS are generally used, and their civilian positioning accuracy can reach within 10 meters. However, in some areas without satellite positioning, such as tunnels, coal mines and other non-open-air or even underground places, relying on satellite positioning is obviously not feasible. At this time, indoor positioning systems are needed to complete the task of providing high-precision position information.

1. Indoor positioning technology

As the demand for indoor positioning increases, a large number of solutions have emerged, including radio frequency identification (RFID) positioning, Bluetooth positioning, Wi-Fi positioning, Zigbee positioning, and ultra-wideband (UWB) positioning. Radio frequency identification positioning realizes presence detection by identifying whether the card is read or not between the card and the card reader, but cannot truly achieve positioning.

In the early days of Bluetooth positioning, a card reader was used to read the RSSI (Received Signal Strength Indication) value indicating the card signal, and the distance between the card reader and the identification card was calculated through RSSI. This method has low positioning accuracy and can be used in obstructed environments. RSSI is greatly affected. Recently, AOA and AOD positioning technologies based on Bluetooth have been slowly developed. Compared with the original positioning technology based on RSSI, the positioning accuracy has been greatly improved. Wi-Fi and Zigbee positioning, like early Bluetooth positioning, are also based on RSSI. Their accuracy is relatively limited and is greatly affected by the environment.

UWB (Ultra-Wide Band) is a carrier-less communication technology that transmits data by sending and receiving nanosecond-level non-sinusoidal narrow pulses, and uses ToF (Time of Arrival) or TDoA (Time Difference of Arrival) algorithms to calculate the number of people or items. Location information, positioning accuracy up to 10 cm. Compared with traditional coarse-precision positioning technologies such as RFID, Bluetooth, Wi-Fi, and Zigbee, the UWB system has the advantages of strong penetration, low power consumption, good anti-multipath effect, high security, low system complexity, and high positioning accuracy. .

Application of coal mine personnel positioning system

For coal mines, especially underground coal mines, the personnel positioning system can obtain the real-time location of people, vehicles, and equipment underground and present it to the computer system on the ground. Managers can keep track of the location information and historical trajectories of underground personnel and vehicles at any time, as well as the installation location of equipment.

For personnel positioning, functions such as attendance management, entry and exit records in hazardous areas, and overcrowding management in hazardous areas can be extended. For vehicle positioning, functions such as vehicle dispatching and automatic traffic light control can be extended. When an accident occurs, rescuers can quickly understand the situation at the scene based on the positioning information of personnel, vehicles, and equipment provided by the positioning system, and take corresponding rescue measures in a timely manner to improve the efficiency of rescue work. The project deployment of the coal mine underground personnel positioning system not only ensures the safety of underground workers, but also greatly improves the level of information management, making management and dispatch more transparent and efficient.

As a professional positioning service solution provider in China, it has been providing overall solutions to the indoor positioning needs of various industries in the past 10 years. For the coal mining industry, the underground personnel positioning system was launched in 2018. After several years of evolution, the stability, maturity, and ease of use of the product have been guaranteed.

1. Equipment architecture

Identification card: It is designated as an object to be worn, which can be a person, vehicle, or equipment. It can send an alarm through a button. When an alarm is received, there will be sound, light, and vibration warnings. Low power consumption, can work for several months on a single charge.

Card reader: Installed in the underground tunnel, it reads the surrounding identification card information and distance, and transmits the tag's ranging information to the ground server.

Position calculation engine: software that calculates the location of the identification card based on the ranging information provided by the card reader.

Business server: Based on the location information provided by the location resolution engine, related services are implemented, including: attendance, real-time location display, historical track query, equipment alarm display, etc.

Handheld instrument: Search for nearby identification cards to obtain the distance between the identification card and the device. It can be separated from the ground server to realize a portable locator.

The coverage radius of the card reader in this solution exceeds 600 meters (line of sight), the positioning accuracy can reach 0.3 meters (line of sight), and the number of concurrent tags in a single area exceeds 400.

2.Business functions

Real-time location display: Use the personnel positioning system to locate the location information and distribution of underground personnel in real time, and monitor the trajectory of personnel in real time.

Statistics on the number of people working underground: Real-time statistics on the number of people working underground. When a serious accident occurs, employees can be quickly gathered for roll call statistics, and the real-time location of employees who have not arrived can be confirmed to carry out rescue operations to avoid casualties.

Attendance management for entry and exit of wells: Develop attendance tasks, and count the time personnel enter and exit the well, the length of time they work on the job, etc. Management can quickly check on-the-job status, and monthly statistical working hours can be directly used as a reference for attendance review based on platform data.

Abnormal emergency alarm: When managers encounter an emergency, they can issue emergency instructions to prompt personnel to evacuate. Tags worn by personnel will vibrate to remind them to stay away from the area.

SOS active alarm: When encountering danger, on-site personnel can use the one-click help button to send out a distress alarm message in a timely manner. After receiving the alarm signal, management personnel can determine the location of the person in danger through personnel positioning and implement on-site emergency response in a timely manner.

Coal mine safety is more important than Mount Tai!

Safety production is no small matter. Only by meeting the premise of safety production can an enterprise develop sustainably. It is hoped that indoor positioning technology can be applied to more industries as soon as possible in the future, and combined with high technologies such as sensing technology and big data to protect the safety of people's lives and property to a greater extent and provide strong backing for safe production management.

The safety production of coal mines has a long way to go and is more important than Mount Tai. It is closely related to every coal miner and enterprise and should receive sufficient attention. We hope that coal mines will be safe and people and mines will be safe!