Design of Personnel Position System of Mine Based on The Average Of RSSI

Wang Xue and Song Shu Zhong Li Meng Electronic and information engineering institute Computer engineering department

Henan University of Science and Technology Luoyang Insititute of Technology LuoYang 471000,China LuoYang 471000,China

wangxue6089936@163.com icelm@sina.com

Abstract: Due to the coal mine production environment,

there often have the bad gas coal-dust explosion, fire, floods and other security hidden danger, coal mine safety accidents occur frequently. This paper introduces a design method of using the average of RSSI miners positioning system: use of personnel carries out the location of the machine, the positioning machine collect the base RSSI value and coordinates on the top of the collection of several positioning, through the collection of value to RSSI averaged calculation thus selection signal strength to the mean of RSSI value, these constitute list next RSSI value through the channel attenuation model into the corresponding distance measurement algorithm, using the trilateral out the orientation of the coordinates of the machine. At last, this system can communicate by the positioning base stations, gateway and ground of PC. It realize the quickly location of the miners and attendance tracking management, and can provide effective fast relief help to the sudden mine accidents. It also take a good stimulative effect for the coal mine safety in production.

Key words the average of rssi; personnel position system; coal mine safety

I. INTRODUCTION

Person-location under coal mine and check on work manage system is one of the important infrastructure to maintain the safety of mine and protect miners [1]. The purpose of the system is to solve the shortage of the detection of the underground coal mine and positioning equipment. This system can located and monitor person automatically under mine. At the same time, it can conduct daily attendance and monito r. Positioning system not only p lay an important role in accident, and can be used for daily management. It have very important sense for command rescue work, reduce property loss and injuries[2].

The current stage of person-location under coal mine and check on work manage system mainly use the RFID technology to locate and trace the staff in mine. Some problems of this technology such as short communicat ion distance, leakage of the reading card when many people in the positioning base station at the same t ime. It can not achive the signal coverage and high precise position of the staff. It is not a real coal mine personnel positioning system but a system of staff safety attendance in coal mine.

As the research of self-localization systems based on ZigBee[3], coal mine personnel positioning system based on ZigBee technology have some preliminary applicat ion. Coal mine personnel positioning system use of the average of RSSI also based on ZigBee wireless network. At the hardware, positioning node and base station was designed by JN5139

node. Several base station was arranged on the top position in the underground tunnels. When the staff carries the positioning nodes into the corresponding communicat ion range, the node send position request and receive the RSSI value and the base coordinate from the base station. Then do average for these values. Put these values as a choice standard, then select the launch RSSI values from three base station and the receiving RSSI values from positioning node. Turn the RSSI values into the distance by the attenuation theories. At the last, calculate the coordinate value using the three-sided measurement. The whole system is made up of the network on the ground and under the ground. It can eliminate the ground management personnel s blind vision spots and enhance the miner s rapid response capability when the mine disasters happen.

RSSI based on the orientation of reference that through the nodes and communications between the mobile node get RSSI value, the wireless signals . Transmission path loss model will RSSI value into the distance between the nodes, and then the calculation method of the mobile node calculate position. RSSI positioning method based on a complete basic orientation process main ly includes two stages: RSSI ranging stage and Coordinate calculation stage.

RSSI ranging phase, the communicat ion between the two sides according to the RSSI value calcu late the distance between the nodes. Mobile node and Reference node communicat ion, mobile node get both sides of the communicat ion RSSI value, based on the choice of radio transmission path loss model Type computed his reference and the distance between the nodes. In the coordinate calculation stage, based on data from a reference node distance between the mobile node, the mobile node according to a certain sit Standard calculat ion method is used to calculate the position itself.

Coal mine underground complex geological structure, there are all kinds of risk factors, underground staff working in deep from the ground Underground tunnels and heading the district, need to have certain mechanism to let the ground monitoring personnel to master the underground a personnel For informat ion, when you meet the emergency can inform the related personnel evacuation in time, when the accident happened by historical data Carry out effect ive rescue. This paper proposes a wireless sensor network based on the orientation system of the mine personnel in coal pit. The Positioning system by mult iple wireless sensor network consists of the underground wireless location parts, data

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Proceeding of the IEEEInternational Conference on Automation and Logistics

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communicat ion part and the ground monitoring center Composition.

II. STRUCTURE OF T HE SYSTEM DESIGN

The whole system is made up of the network on the ground and under the ground. As shown in Fig 1.

The network on the ground is composed of several sub-systems:(1) underground location subsystem: it collect the positioning coordinate informat ion from the pos itioning base station and displayed the informat ion in the interface. (2) the early warning system: on the one hand, according to the testing data of the mine conditions, if there is any abnormal, it can make warning instructions to the miners, so as to guide the miner evacuation quickly; on the other hand, miners give warning signal by alarm button carried on the positioning node. Then the interface on the ground can display specific informat ion of the alarm people. (3) communicat ion sub-system: it can realize the data communication between the monitor center of the base position and underground positioning base, it also can realize personnel direct communicat ion through the base station. (4) data acquisition system: put the state of the miners, the analysis of location informat ion , processing, written to the database, and then realize man-machine interaction through the geographic informat ion and personnel informat ion processing process. As the following fig 1 show:

exchange

position station Position station Position station

Surface monitoring

further station

staff carried node staff carried node

fibre transport interface

mine fibre

RS485 repeater

ground

staff carried node

Fig 1 Design of a system maps Underground network: positioning station, staff location

node, transport interface, bus repeater, transmitting cable; below is the introduce of underground device: (1)terminal of positioning node: it give off wireless signal carried ID(personnel informat ion, t ime message, location informat ion, etc), the positioning station underground received the signal, then send it out to surface system by t ransmission networks, the data was handled by serve. It can achieve many function such as attendance, location, search, colligation management, shared informat ion and network transmission, etc; (2) positioning station node underground: it was installed on the mine tunnel. The node is powered by itself and

explosion-proof batteries. When it received the positioning node s message, it will add time and number at first. It also was deposited by RAM. Once the base station accept the inquires of serve system, the data will be upload; (3) 485 bus networks; (4) 485 bus repeater( when the positioning station was far from each other , the signal will attenuated seriously. At this point, the bus repeaters must be installed.)

The implementation plan of system can be describe: With the help of the software, the monitoring center server on the ground conduct data collection and information gathering for positioning station. Based on instruction set, the serve transfer the related data to the ground by transmission network.. After the informat ion was analyzed and processed, it will reflect the dynamic d istribution of underground staff on the system server. Thus, fulfill the purpose of digital management on the surface about the safe state of underground.

Miners on the positioning and management software system has expanded conveniently, high reliab ility, safety of strong, management He and other advantages, system will miners dynamic d istribution of gas concentration, temperature, humid ity, and communication system state, Alarm informat ion, and other important data in the monitor host interface to reflect in real time, so as to realize safe state in underground The purpose of the digital management inoue; At the same time in the safety accident happens, through this system can clear the men The specific position, for emergency rescue and disaster relief and rescue work safety the efficiency of provides great convenience. In underground staff and management software system of location, it needs more work. To be able to perfect, according to the specific research on medium or large system, can add more system function, For example the workload of all underground analysis, according to the different kinds of work efficiency to miners Work more scientific and reasonable distribution. Combined with the actual need to increase the mine video monitoring function, that is all reach visualization and digital organically, better to provide the guarantee of safety production in coal mine.

III. T HE HARDWARE DESIGN

For the design of hardware, need to refer to the size of sleep current, sending and receiving current, so as to meet the requirement of power dissipation. The node is always keep in a sleep state. In short, comparison of consumption, cost, communicat ions region and processor, I choose the JN5139 chip because it have merit such as lower dormant current and long distance. Use the JN5139 modules by AionTech group, dormant current of 2.8 miliamperes, voltage range of 2.7~3.6V, receiv ing sensitivity of -96.5dBm, trans mit and receive current of 37mA, 21 of address -select signal for I/O port[4]. After the selection of the hardware, upload the boot, so as to realize the in itialization of hardware, and upload the corresponding drive.

The working voltage of the node is 3.7V. The node consists of RF module, watchdog, power management, status

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light, vib rator, voice ch ip, speaker and battery. The watchdog was used to check the status of the processor. The processor will send data to watchdog regularly. The power management unit is used to detect the battery s power by obtain the acquisition of battery s power supply voltage. When the voltage is lower than the default voltage, the circuit send out data to processor, so as to call the staff to charge by indicator light and voice circuit.

Positioning base station is responsible for communicat ion with the positioning node, deal with the informat ion from positioning node previously, then upload to system server. Its voltage rat ing is 18V, it consists of RF module, control processor, power management, memorizer, RS485 transceiver, status light and ethernet interface module, etc. When the RF module receive the wireless signal, the processor analyze the data. After that, put it in the storage. As the base station received the inquired signal, it will send the saved data to serve by RS485 transceiver. At this point, the base station was divide into JN5139 router station and JN5139 coodinator for the sake of the data s better acquisition and personnel s positioning. As the following fig 2 show:

control processor

watchdog module

powermanagement ethernet module

JN5139 wilessmodule

memory module

Ethernetconverter

Fig 2 Hardware module chart

IV. LOCALIZATION ALGORIT HM AND THE DESIGN OF SOFTWARE

Existing localizat ion algorithm methods main ly has the no ranging localizat ion algorithm and the localizat ion algorithm based on location. No ranging localizat ion algorithm is unsuited for coal mine because the surroundings is sole and linearity distribution. On account of it not measuring the distance between the nodes, but measuring the hop between the nodes by the network connection, estimate the distance by the anchor nodes, at the last , calculate the position coordinates. The localization algorithm based on location have the following kinds of forms: (1) TOA: measuring the d istance with t ravel t ime. GPS is with this technique. It is expensive and need time synchronization. (2) TDOA: system uses ultrasonic echo and reflection of the t ime difference to measure the distance test. It is still limited by the ultrasound travel and NLOS problem. (3) AOA: Estimate the signal s direction of neighbor node. Achieve the measure of distance by the angle of signal s transmission. Furthermore, it require additional hardware. (4) RSSI: measuring the distance through the signal attenuation model. Because node itself

have the ability of measure RSSI. The algorithm doesn t require any excess hardware. So it is a low power, cheap range finder technology. By using this algorithm, it can realize ideal positioning requirement for coal mine.

Detect field intensity of receiving signal and transmit so as to evaluate the distance by attenuation channel models. Because the complexity of modeling, reflection, the impact of the multi-path dissemination, NLOS and antenna gain. There are many propagation loss. Layout base station known location equally spaced through the underground tunnels. It was used to take position of personnel carried positioning node. Position station broadcast data frames in proper order. Location node calculate distance between staff and base station. Get the accurate RSSI by average value, then calculate the positioning node s position take advantage of three distance. Assume the coordinate of base station is

11, yx , 22 , yx 33 , yx , the coordinate of positioning node R is

yx ,.

The distance between node R and R1, R2, R3 is surrounded by d1,d2,d3, using that formula:

2 21 1 1

2 22 2 2

2 23 3 3

(1)

d x x y y

d x x y y

d x x y y

Draw 1 2 2 2 2 2 2

1 3 1 3 1 3 1 3 3 12 2 2 2 2 2

2 3 2 3 2 3 2 3 3 2

2 2(2)

2 2

x x y y x x y y d dxy x x y y x x y y d d

.

There is some errors in the actual distance existing. Therefore, we can evaluate position coordinates better by increasing the number of positioning station to improve the distance of the redundancy.

The designing mentality of system is reg ister the location informat ion in base station by wireless be composed of underground location node and base station. And then realize the information flow between persons on the surface and persons under the mine with series of software on the PC. There are a variety of system software: (1) The verificat ion management system of PC: it consists of personnel informat ion management, geographic environmental informat ion of mine, deploying information of position, data acquisition software, system management and monitoring software. (2) Troubleshoot software: it consists of personnel basic information, power manager implements a control procedure and signal alarming program. The function of software is measure the staff s information such as names and take over control commands from base station and monitoring center. In addit ion, it also can give the alarm as soon as. (3) Location software of base station: take over positioning request from positioning node, then send out response, memory the RSSI of positioning node and perform computations in director. On the side, it can extend routing protocol so as to make more positioning station put in

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network. (4) RS485 repeater s software: its function just as data acquisition s software. The difference is the external input or output is RS485 signal. (5) switchboard s software: As data interface to bring about communication between surface mesh and underground mesh. Different software based on the different development platform. Should take full account of the harmonic stability of system when structure software system. Building up the most rational software architecture. As the following fig 3 show:

Real timemonitoring

Software of positioning

Dataacquisitionsoftware

Systemmanagement

Personnel information management,geographic envionmental information,

device s location information

Localization software ofbase station

RS485 repeater

switchboard

Fig 3: Software framework

EPILOGUE

Positioning system can select the most appropriate positioning base station by mean value of RSSI and reflect personnel location informat ion to ground monitoring center of the computer system. JN5139 node used by system have the advantage of low power consumption and cost. Through the underground positioning system, can eliminate the blind zone of the rig workers to miner, have the knowledge of the real-t ime working condition. Improve the efficiency of the coal mine p roduction greatly. Give great stimulative effect for coal mine production safety and be able to provide a high efficiency rescue plan for coal mine accident. Wireless sensor network development, make as one of the key technologies of the positioning technology also received more and more attention. This On WSN location technology a field research, in v iew of personal ability and study time limited, and there are still a lot of The place o f foot, such as the RSSI fast fading and slow decline phenomenon can very good modeling analysis, especially slow decline now. In the location of the effect of the quantitative description of no. Such lack of hope to get experts guidance, and Hope can have more researchers to join the field, in order to better and faster wireless sensor network to promote the application and development. Combined with RSSI location technology for research, the complet ion of the coal mine monitoring and management system of location positioning son. The design and realizat ion of the system work. In embedded operating system TinyOS and Windows operating system using NesC respectively Language and Microsoft Visual c + + translation environment completed the positioning subsystem in formation acquisition, cable transmission and positioning calculationEach module. Long-term test results show that the system is stable, to

provide users with higher precision service. Miners on the positioning and management software system, after rapid prototype method and the investigation and analysis to finally realize System may allow more client software and at the same time to access data, and homework. Accurate and timely collection of real-time data, including staff Numbers informat ion, data information (Humidity, gas concentration, etc.).Distribution of miners real-time accurate positioning, real-t ime display field environmental data.On the scene of events of real-time data displayed, can v iew the latest article 1000,Record.Personnel activities of the track informat ion query.Personnel of attendance management, output statistical reports.The alarm information output, the inquiry statistics, in view of the gas concentration, temperature, humid ity anomaliesThe icon flash the hint, also can use voice call the police.The wireless delivery of information support alarm functions, with the aid of the GSM network, to reach a certain level alarmAlarm parameters, according to the predetermined receiving personnel, mass short information to give the police. The system can automatically on the database timing maintenance compression, ensure data validity and integrity.

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