Summary of GIS Coal Mine Safety Real-time Monitoring System Based on ARM

1. Introduction

Due to the special working environment of coal mine production, the production process is more dangerous and unsafe than the general industry. With the continuous increase in coal mining, safety issues have become increasingly serious, and various major accidents are often reported in the media. All this warns the severe situation of coal mine production safety and the necessity and urgency of improving coal mine production safety. With the rapid development of computer, Internet and communication technology, the application of GIS-based monitoring system has become an important means of real-time monitoring of coal mine safety. GIS coal mine safety real-time monitoring system can automatically display various data such as gas concentration, air volume, equipment status, etc. measured by sensors on electronic maps. Combined with the underground personnel positioning system, the location of underground workers can also be displayed on the electronic map. System data transmission is carried out by computer networks such as local area networks and the Internet. With the rapid development of computer technology and mobile communication technology, various monitoring data information is transmitted to the monitoring center in real time through the communication network and transmitted to the responsible person at regular intervals, so that the relevant responsible person can know the safety situation of coal mines at any time and any place, which will greatly promote the safety production management of coal mines. At the same time, for mines located in remote areas, with limited computer network resources, it is also necessary and practical to use mobile communication wireless transmission.

2. System composition and working principle

2.1 System composition

The ARM-based GIS coal mine safety real-time monitoring system mainly includes three parts: mine end, GSM communication network, and GIS monitoring center.

The mine end mainly includes GPS module, GSM module and ARM control module. GPS module and GSM module realize positioning and wireless transmission; ARM control module realizes data collection and data processing, and is the main module of the mine end. It is an ARM embedded device carried by the staff, which can be shared by several people. Before going down to work, as long as the fingerprint is entered to verify the personal information related to it, the GIS center database can accurately record the staff going down to the mine. As a data collection, processing and control module, the core function is to continuously obtain the location information of the underground staff and the gas concentration, wind speed and other parameter values, and send this information to the GIS monitoring center through the GSM communication network, and can receive the dispatch command from the monitoring center at any time.

The GSM communication network is used to complete the information transmission between the mine end and the GIS monitoring and dispatching center, using the SMS short message service of the existing GSM mobile information system.

The GIS monitoring center is the core of the entire system. It is an intelligent monitoring and management center based on GIS. It can display the location of underground personnel, gas concentration or equipment status and other information at any time, and control the corresponding equipment (manually or automatically) based on the data information.

2.2 System Working Principle

The mine end first collects the dynamic position (longitude, latitude, altitude), time, status, and environmental information such as gas concentration, wind speed, temperature, etc. of the underground workers in real time. Then, after the data processing module and the control module process the data, the information is transmitted to the GIS monitoring center in real time through the GSM mobile communication network through the GSM module. The workers and various parameters such as temperature, wind speed, pressure, gas concentration, carbon monoxide concentration, etc. at their locations are accurately located and displayed on an electronic map with powerful geographic information processing and query functions, and these parameters can be monitored and queried. When a parameter exceeds a certain safety value, an alarm is issued, and the monitoring center sends various monitoring and dispatching signals to the mine through the GPS mobile communication network to eliminate various hidden dangers and ensure safe production in coal mines.

3. Design of mine hardware

3.1 GPS Module

The GPS module is mainly used for positioning. By receiving GPS satellite signals, the location of the person to be located is calculated. The GPS module consists of a frequency converter, a signal channel, and an ARM chip. The GPS module sends the coordinates of the person to be located to the main controller through the serial port; the GPS module needs to be equipped with a special GPS antenna to receive GPS satellite signals. Generally, it is necessary to receive more than three GPS satellite signals for accurate positioning. For convenience, the GPS module is designed to be installed on the safety helmet of the underground personnel.

Taking into account the actual conditions of most coal mines, the GPS module uses GARMIN's GPS25LP.

3.2 GSM Module

The communication between underground personnel and the monitoring center is achieved through the GSM module. The short message service of the GSM mobile communication system is used for communication in the coal mine real-time monitoring system. The short message service belongs to the telecommunications service of the GSM digital mobile communication system. It has the characteristics of being online at any time, no dialing required, low price, and wide coverage. It is particularly suitable for applications that require frequent transmission of small-volume data. This module design uses SIEMENS's TC35i wireless GSM module.

3.3 ARM Control Module

The ARM control module is the core control component of the mine end. It is an embedded system based on the ARM processor. Its main function is to process data and control the various components of the mine end to perform corresponding operations according to the requirements of the communication protocol. The system includes CPU memory, I/O interface and various control logic circuits. The first task of module design is to select the embedded processor. What kind of embedded processor core is used in a system mainly depends on factors such as the application field, user needs, cost, and the difficulty of development. After determining which embedded processor core to use, the next step is to combine the actual situation and consider the needs of the system peripherals to select a suitable processor. Combined with the current actual situation of coal mines, the AT91R40008 microprocessor was selected. This processor is a branch of the 16/32-bit microprocessor family based on the processor core. It adopts a high-performance 32-bit structure, has a high-density 16-bit instruction set and low power consumption. The series combines the processor core with on-chip high-speed memory and multiple peripheral functions on a microprocessor, providing a flexible and low-cost solution for a large number of computer embedded control applications.

After determining the components, the modules and devices are connected to the ARM embedded system development board using the corresponding communication cables. According to the actual situation, a small number of peripheral devices and power modules are added to form a hardware platform for system integration at the mine end. The relationship between the modules is shown in Figure 1.

4. Software design at the mine end

In the mine, the acquisition of location information, the sending and receiving of short messages, the processing of internal data and the driving of peripheral control devices are all completed under the unified control of the ARM chip, which requires necessary programming of the embedded system. This system is based on the μClinux operating system and is programmed in C language. [page]

4.1 Establishment of μClinux development environment

In order to realize the development of application systems based on μClinux, it is necessary to establish or have a complete μClinux development environment. The application development environment based on the μClinux operating system is generally composed of the target system hardware development board and the host PC. The target hardware development board is used to run the operating system and system application software, while the kernel compilation of the operating system used by the target board, the development and debugging of the application program need to be completed through the host PC. The connection between the two parties is generally established through the serial port, parallel port or Ethernet interface.

4.2 System Software Process

The mine end is composed of AT91R40008 development board, TC35i, GPS15 OEM board. The AT91R40008 development board has two serial ports, one of which is connected to the GPS receiving module to receive the location information from the satellite, and the other serial port is connected to TC35i to package the received positioning data into a short message format and send it out through the existing communication network to achieve personnel positioning and monitoring management. The workflow of the entire system is as follows: After the system is powered on and reset, it will self-check and initialize. After the GPS module is turned on for the first time, it will automatically search for information such as the almanac and the almanac. After receiving the positioning information, it will encode and decode the location information such as longitude and latitude we need, package it into a short message format, and send it to the user terminal or switchboard through the TC35i module to achieve global positioning and monitoring management. The flow chart of the entire system is shown in Figure 2:

Figure 2 System flow chart

5. Conclusion

The GIS coal mine safety real-time monitoring system based on ARM embedded technology mainly utilizes the powerful functions of ARM and combines GRP and GSM technologies to realize real-time monitoring of coal mine safety at the mine end. Compared with the traditional mine end that uses 8-bit single-chip microcomputer as the main control chip, its complex monitoring function is stronger, the system is more flexible, the applicability is better, and it has greater scalability. It will have a certain driving effect on strengthening coal mine safety production management, and has good social and economic benefits.