WO2013026461A1

WO2013026461A1 - Method, positioning unit and system for communication in a mine

Info

Publication number: WO2013026461A1
Application number: PCT/EP2011/064280
Authority: WO
Inventors: Krister Landernäs; Mikael Gidlund; Mikael ÅKERHOLM; Jonas Neander
Original assignee: Abb Research Ltd
Priority date: 2011-08-19
Filing date: 2011-08-19
Publication date: 2013-02-28

Abstract

It is presented a method for safe communication between a portable positioning unit and a tracking unit in a mine. By means of the present method the location of the portable positioning unit and thus the object carrying the unit can be determined with a higher degree of certainty The method comprises the steps of determining (SI) location data pertaining to the location of the portable positioning unit in the mine, generating (S2) a location message comprising the location data, wherein the generating of the location message further includes providing the location data with a message number defining a sequence number of the location message and redundancy data, and transmitting (S3) the location message for reception by the tracking unit. A portable positioning unit and a tracking system are also presented herein.

Description

METHOD, POSITIONING UNIT AND SYSTEM FOR COMMUNICATION

IN A MINE

TECHNICAL FIELD

The present disclosure generally relates to mining and in particular to communication in a mine for determining the location of an object in the mine.

BACKGROUND

For reasons of safety it is sometimes desirable to provide mines, such as subterranean mines, with a monitoring system for monitoring any objects located in the mine.

Examples of such objects are mining personnel and mining equipment. By knowing the location of the objects, decisions regarding e.g. the movement of equipment, blasting or ventilation control maybe taken with reduced risks with respect to the objects in the mine.

US2008137589 discloses a wireless mine tracking monitoring and rescue

communications system It describes a location information network for personnel and assets in underground mines. The network includes wireless access units and subnetwork controllers, active wireless locator /messenger tags, network controller(s), and enterprise servers running application control software. The wireless access units are installed in mine entries and crosscuts and tracks active wireless locator /messenger tags. The active tags maybe worn by mine personnel or installed in mining equipment. The network subsystems form relay networks that wirelessly carry telemetry and control data without the need to penetrate the earth. The subsystems determine the location of persons and assets underground and monitor safety-related information, which can be used for disaster avoidance, early warning of impending disaster, and improved rescue effectiveness. In view of the disclosure of US2008137589 it would however be desirable to improve the communication of an underground mine communications system

SUMMARY

A general object of the present disclosure is to improve the safety of wireless or wired communication in a mine. Thus, in a first aspect of the present disclosure there is provided a method for safe communication between a portable positioning unit and a tracking unit in a mine, wherein the method comprises: cfetermining location data pertaining to the location of the portable positioning unit in the mine; generating a location message comprising the location data, wherein the generating of the location message further includes providing the location data with a message number defining a sequence number of the location message, and redundancy data; and trarismitting the location message for reception by the tracking unit.

By providing the location data with redundancy data and a message number and thus forming a location message, the probability of incorrect / corrupted location data is reduced on the receiver end, e.g. the tracking unit.

Beneficially, the safety of objects such as mining personnel or mining equipment is improved Thus, safe and reliable information can be provided e.g. when planning the movement of large mining equipment in the mine. Furthermore, the operation of the ventilation system of the mine can be controlled more energy efficiently e.g. by utilising ventilation on demand (VOD), thus reducing energy costs, if the position of mining personnel can reliably be determined Moreover, the reliable positioning information which can be obtained by mining operators by means of the present disclosure provides for more efficient evacuation and rescue operations, and it can be ensured that personnel and sensitive equipment is not located in the mine when explosives are used

One embodiment comprises encrypting the location data. Thereby more secure communication maybe provided and risk of location data corruption is reduced

In one embodiment the steps of determining, forming and transmitting are repeated periodically. By providing periodic transmission of the location messages, the receiving end of the location message maybe able to determine whether a location message is missing, i.e. if a location message did not arrive at an expected time, and act accordingly for instance by requesting resending of the location message.

In one embodiment the location message is sent via a communications protocol having a safety layer for def ining the sequence numbering and adding the redundancy data. One embodiment comprises receiving a resend location message request based on redundancy data check failure, and resending the location message.

In one embodiment the redundancy data is a checksum. Thereby more reliable error detection maybe possible with regards to the location data. Preferably, the method according to the first aspect can be implemented as program code stored on a computer readable medium thereby defining a computer program product. When the program code is executed, it can perform any of the method steps according to the first aspect.

According to a second aspect of the present disclosure there is provided a portable positioning unit for safe communication in a mine, wherein the portable positioning unit comprises: a processing system arranged to determine location data pertaining to the location of the portable positioning unit; to generate a location message comprising the location data, a message number defining a sequence number of the location message and redundancy data, wherein the processing system is arranged to provide the location data with the message number and the redundancy data; and an antenna unit arranged to transmit the location message.

In one embodiment the portable positioning unit is arranged to determine the location data based on external communication signals received by the antenna unit and processed by the processing system. The process of determining the location data can for instance be based on triangulation with respect to a wireless access unit or wireless access units which with the portable positioning unit is in communication with. Another alternative is to determine the location data and hence the current location of the portable positioning unit can for instance be based on Received Signal Strength

Indication (RSSI) of the external communication signal provided by one or more nearby wireless access units and received by the portable positioning unit, and comparing the signal strength with reference values in a look-up table.

In one embodiment the processing system is arranged to encrypt the location data.

In one embodiment the processing system is arranged to determine location data, and generate and transmit a location message periodically. In one embodiment the location message is sent via a protocol having a safety layer for defining the sequence numbering and adding the redundancy data

According to a third aspect of the present disclosure there is provided a tracking system for safe communication of location messages in a mine, which tracking system comprises: a portable positioning unit according to the second aspect presented herein; a tracking unit; and a plurality of wireless access units for distributed arrangement in the mine, wherein the portable positioning unit is arranged to transmit a location message to a wireless access unit of the plurality of wireless access units, wherein the wireless access unit is arranged to provide the location message to the tracking unit.

In one embodiment the portable positioning unit is arranged to interact with at least one of the plurality of wireless access units in order to determine the location of the portable positioning unit.

In one embodiment any of the tracking unit and the wireless access unit is arranged to transmit a resend location message request based on redundancy data check failure, wherein the portable positioning unit is arranged to resend the location message to the wireless access unit.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, byway of example, with reference to the accompanying drawings, in which:

Fig 1 is a schematic view of a portable positioning unit and a wireless access unit. Fig. 2 is a schematic view of a tracking system arranged in a mine and comprising a portable positioning unit and a plurality of wireless access units.

Fig. 3 is a flowchart describing an example of a method of safe communication

a portable positioning unit and a tracking unit in a mine. DETAILED DE SCRIPTION

The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments are shown. It is to be noted, however, that the tracking system and its components and the methods disclosed herein maybe embodied in many different forms and should not be construed as limited to the embodiments set forth hereinafter; rather, these embodiments are provided byway of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout the description.

In the following, examples of a portable positioning unit, a wireless access unit, and a tracking system will be described in more detail. The portable positioning unit and a plurality of wireless access units forms the tracking system which is arranged to provide positioning information of the portable positioning unit and any object carrying the portable positioning unit.

Fig. 1 shows an example of a portable positioning unit 1 comprising a cover 3, an antenna unit 5, a processing system 7 with a memory unit 9, a battery unit 13 for powering the portable positioning unit 1, and an electrical connection 11

the processing system 7 and the antenna unit 5. The memory 9 may comprise software, i.e. program code, which when executed by the processing system 7 performs the methods presented herein. Fig. 1 further illustrates a wireless access unit 15. The wireless access unit 15 has a cover 17, and comprises an antenna unit 19, a processor 21, an electrical connection 23

the processor 21 and the antenna unit 19, and an output 25 via which the processor 21 can output data, such as location messages. The portable positioning unit 1 and the wireless access unit 15 are adapted to communicate via their respective antenna units 5 and 19, and thus set up a

communication link L. The portable positioning unit 1 and the wireless access unit 15 are adapted to communicate via a common communications protocol which will be described in more detail herebelow

The portable positioning unit 1 maybe any kind of mobile communications device able to cfeterrnine its position in a mine including an underground mine, and which is able to wirelessly communicate with a plurality of wireless access units 15 arranged in the mine such that the position of the portable positioning unit can be determined In view of the above,

a portable positioning device 1 and a wireless access unit 15 as disclosed herein mainly concerns the position or location of the portable positioning device 1.

Fig 2 is a schematic view of a tracking system 27 of an underground mine 29. The tracking system 27 comprises one or more portable positioning units 1, a plurality of wireless access units 15, and a tracking unit 28. The tracking unit 28 may comprise a processing unit enabling communication with the wireless access units 15 and one or more portable positioning units 1, and a display screen for presenting the location of the one or more portable positioning units in the mine 29.

The wireless access units 15 are typically distributed in shafts 31 of the mine 29 such that communication

a portable positioning unit 1 and a wireless access unit 15 is possible essentially at any position in the mine 29.

Typically, a portable positioning unit 1 located in the mine 29 communicates with one or more of the wireless access units 15. By communicating with nearby wireless access units 15, location data pertaining to the location of the portable positioning unit 1 can be determined In one embodiment, the processing system 7 is arranged to receive signals from wireless access units 15, and in particular from a nearby located wireless access unit. In Fig. 2 for instance, the portable positioning unit 1 can communicate with at least one of the two nearby wireless access units 15-1 and 15-2. By triangulation or by determining a signal strength of the signals received from one or more wireless access unit 15, the position X of the portable positioning unit 1 can be determined, and thus the position of a person P carrying the portable positioning unit 1. In one embodiment, in a step SI as shown in Fig.3, location data pertaining to the location X of the portable positioning unit 1 is determined by means of the processing system 7. Alternatively, the location data and thus the position X of the of the portable positioning unit 1 can be determined in one of the nearby wireless access units 15, e.g 15-1 or 15-2 when having set up a communications link with the portable positioning unit 1, and having received a signal from the portable positioning unit 1. In this case the position of the portable positioning unit 1 could be determined by similar methods as when the position X is determined in the portable positioning unit 1.

When the location data has been determined, a location message including the location data is generated in a step S2. The location message further includes a message number defining the sequence number of the location message. The location message also comprises redundancy data, thereby allowing error detection concerning the location message when having been received by either a wireless access unit 15 which with the portable positioning unit 1 is in communication with or by the tracking unit 28. In the example of Fig. 2, the portable positioning unit 1 is in communication with wireless access units 15-1 and 15-2. In embodiments in which the location message is generated by the portable positioning unit 1, the location message is transmitted to a wireless access unit 15 with which the portable positioning unit 1 is able to communicate in view of the topology of the mine. Thus, in the example given in Fig. 2, the portable positioning unit 1 is able to communicate with at least one of the wireless access units 15-1 and 15-2. The location message is hence transmitted to at least one of the wireless access units 15-1 and 15-2.

A wireless access unit 15 which receives a location message, i.e. is in communication with the portable positioning unit 1, will in the following be referred to as a receiving wireless access unit.

When a receiving wireless access unit 15 has received the location message, in one embodiment it is automatically transmitted from the receiving wireless access unit 15 to the tracking unit 28 via the output 25. In one embodiment the communication between the wireless access units 15 and the tracking unit 28 is by means of wired

communication.

In one embodiment, an error correction check is performed by a receiving wireless access unit 15 when having received the location message. Thus the redundancy data is utilised to cfetermine correct reception of the location data and message number. If it is determined that the location data is non-corrupted, i.e. it is complete and correct, it is transmitted by the wireless access unit 15 to the tracking unit 28. On the other hand, if it is determined by the receiving wireless access unit 15 that the location data is corrupted, i.e. incomplete and incorrect thus not coriforming with the location message transmitted by the portable positioning unit 1, the receiving wireless access unit 15 is adapted to transmit a resend location message request to the portable positioning unit 1. Thus, if there is a redundancy data check failure, the receiving wireless access unit 15 transmits a resend location message request. In response to receiving the resend location message request in a step S4, the portable positioning unit 1 resends the location message in a step S5 to the receiving wireless access unit 15. The process of resending is in one embodiment repeated until the location message has been received in its correct form, i.e. in the form it was intended to be received

When the tracking unit 28 receives the location message from a receiving wireless access unit 15, an error correction check is performed by the tracking unit 28. If it is determined that the location data is non-corrupted, i.e. it is complete and correct, the location data is registered by the tracking unit 28. Furthermore, the location data can in one embodiment also be presented on the display screen of the tracking unit 28. On the other hand, if it is determined by the tracking unit 28 that the location data is corrupted, i.e. incomplete and incorrect thus not conforming with the location message transmitted by the receiving wireless access unit 15 and hence not conforming with the location message transmitted by the portable positioning unit 1, the tracking unit 28 is adapted to transmit a resend location message request to the portable positioning unit 1 via the plurality of wireless access units 15. In one embodiment all of the plurality of wireless access units 15 is arranged to receive the resend location message request, wherein all wireless access unit 15 transmit the request at their respective location in the mine.

Alternatively, the receiving wireless access unit 15 which was responsible for sending the location message to the tracking unit 28 is provided with the resend location message request. Thereby the receiving wireless access unit 15 can transmit the request to the portable positioning unit 1.

In one embodiment, the redundancy data of the location message for determining whether the location message is corrupt is utilised only by the tracking unit 28 when having been received from a receiving wireless access unit 15. In this case, the wireless access units are only for relaying the location message from the portable positioning unit 1 to the tracking unit 28 and are hence not arranged to cfetermine whether a received location message is corrupted or not. Beneficially, standard wireless access units may thereby be utilised in such an embodiment, i.e. the wireless access unit need not be able to cfetermine whether the location message is corrupted or not.

In one embodiment, the location message is transmitted periodically. Typically, the period is precfetermined such that the plurality of wireless access units 15 knows when to expect a location message. In case a location message in not received by a wireless access unit 15 at a predetermined time, each wireless access unit 15 may transmit a resend location message request whereby a portable positioning unit 1 located in the mine will resend the location message to a nearby wireless access unit 15.

Beneficially, the redundancy data maybe a checksum, preferably a checksum for the location data, the message number and any other data sent with the location data Alternatively, the redundancy data maybe based on vertical redundancy check, longitudinal redundancy check, cyclic redundancy check or any other suitable method of error detection.

In one embodiment, the location message maybe encrypted Thus, the portable positioning unit, the wireless access units and the tracking unit each utilise secret or public encryption keys for encryption and decryption of the location messages. The location message communication can be implemented via a communication protocol utilised in the tracking system The communication protocol may utilise a designated protocol layer for safety. This layer is assigned to associate the location message with a message number, and to provide redundancy data to the location data and location message. Furthermore, the additional layer may also be responsible for encryption and for periodically trarismitting location messages. In one embodiment, if the location message has been determined to be corrupted, the determining having been carried out by e.g the tracking unit or a wireless access unit, it is merely noted by the tracking unit or the wireless access unit that the location message has been corrupted In this case no further action, e.g no requests for resending the location message is carried out by the tracking unit or wireless access unit. Instead, the tracking system notes that the location message is corrupt. As a result of having determined that the location message is corrupted, the tracking system is arranged to be set in a safe mode. In the safe mode, hazardous operations such as using explosives in the mine are prevented Thus, the safety of any objects present in the mine can be assured

The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.

Claims

1. A method for safe communication between a portable positioning unit (1) and a tracking unit (28) in a mine (29), wherein the method comprises: determining (SI) location data pertaining to the location of the portable positioning unit (1) in the mine (29), generating (S2) a location message comprising the location data, wherein the generating of the location message further includes providing the location data with a message number defining a sequence number of the location message, and redundancy data, and transmitting (S3) the location message for reception by the tracking unit (28).

2. The method as claimed in claim 1, comprising encrypting the location data.

3. The method as claimed in claim 1 or 2, wherein the steps of determining (SI), generating (S2) and transmitting (S3) are repeated periodically.

4. The method as claimed in any of the preceding claims, wherein the location message is sent via a communications protocol having a safety layer for defining the sequence numbering and adding the redundancy data.

5. The method as claimed in any of the preceding claims, comprising receiving (S4) a resend location message request based on redundancy data check failure, and resending (S5) the location message.

6. The method as claimed in any of the preceding claims, wherein the redundancy data is a checksum

7. A computer program product comprising a computer readable medium on which program code is stored, wherein when the program code is executed it is arranged to carry out the method as claimed in any of claims 1-6.

8. A portable positioning unit (1) for safe communication in a mine (29), wherein the portable communications unit (1) comprises: a processing system (7) arranged to determine location data pertaining to the location of the portable positioning unit (1); to generate a location message comprising the location data, a message number defining a sequence number of the location message, and redundancy data, wherein the processing system (7) is arranged to provide the location data with a message number and the redundancy data; and an antenna unit (5) arranged to transmit the location message.

9. The portable positioning unit (1) as claimed in claim 8, arranged to cfetermine the location data based on external communication signals received by the antenna unit (5) and processed by the processing system (7).

10. The portable positioning unit (1) as claimed in claim 8 or 9, wherein the processing system (7) is arranged to encrypt the location data.

11. The portable positioning unit (1) as claimed in any of claims 8-10, wherein the processing system (7) is arranged to determine location data, and generate and transmit a location message periodically.

12. The portable positioning unit (1) as claimed in any of claims 8-11, wherein the location message is sent via a protocol having a safety layer for defining the sequence numbering and adding the redundancy data.

13. A tracking system (27) for safe communication of location messages in a mine (29), which tracking system (27) comprises: a portable positioning unit (1) as claimed in any of claims 8-12, a tracking unit (28), and a plurality of wireless access units (15) for distributed arrangement in the mine

(29), wherein the portable positioning unit (1) is arranged to transmit a location message to a wireless access unit (15) of the plurality of wireless access units (15), wherein the wireless access unit (15) is arranged to provide the location message to the tracking unit (28).

14. The tracking system (27) as claimed in claim 13, wherein the portable positioning unit (1) is arranged to interact with at least one of the plurality of wireless access units (15) in order to determine the location of the portable positioning unit (1).

15. The tracking system (27) as claimed in claim 13 or 14, wherein any of the tracking unit (28) and the wireless access unit (15) is arranged to transmit a resend location message request based on redundancy data check failure, wherein the portable positioning unit (1) is arranged to resend the location message to the wireless access unit