WO2024117948A1

WO2024117948A1 - Method, system, and control unit for handling measurements in an underground environment

Info

Publication number: WO2024117948A1
Application number: PCT/SE2022/051123
Authority: WO
Inventors: Hans WAHLQUIST
Original assignee: Epiroc Rock Drills Aktiebolag
Priority date: 2022-11-30
Filing date: 2022-11-30
Publication date: 2024-06-06

Abstract

A method for handling measurements of air in an underground environment is provided. The method comprises obtaining (201) at least one first measurement of air at a firstposition. The at least one first measurement is measured by a mobile measuring 5equipment in the underground environment. The method comprises obtaining (202) at least one second measurement of air of a stationary measuring equipment that is located at a stationary position in the underground environment. The method comprises in response to determining (203) that the first position is within a predefined range of the stationary position of the stationary measuring equipment, calibrating (205) the at least 10one second measurement based on the at least one first measurement.

Description

METHOD, SYSTEM, AND CONTROL UNIT FOR HANDLING MEASUREMENTS IN AN UNDERGROUND ENVIRONMENT

TECHNICAL FIELD

Embodiments herein relate to a method, a system and a control unit for handling measurements in an underground environment. Furthermore, a computer program and a carrier are also provided herein.

BACKGROUND

Air quality is an important aspect for vehicles and humans working in underground environments. This is particularly true when performing mining operations where the mining operations and vehicles performing said mining operations may generate and/or that emit particles and/or emissions that may have an impact on a working environment. Furthermore, at least a minimum oxygen level is needed to operate vehicles in underground environments, at least if they are operating using combustion engines. To ensure a high air quality in an underground environment, ventilation equipment are arranged to pump fresh air from above ground down into different areas of the underground environment. The ventilation equipment may further be arranged to clean, filter, and/or pump away air with high emissions and particles in the underground environment from said areas. However, ventilating areas in an underground environment can be a complex and difficult task. This is since airflows in underground environments may be complex and also expensive. Furthermore, there may be a limit to an amount of air that can be pumped down into the underground environment and certain areas need to be prioritized. With respect to a power and/or energy limit to always having ventilation pumping air at full effect may also not be sustainable, e.g., with respect to a power and/or energy quota for ventilation. Hence, to be able to plan ventilation for an underground environment in an efficient manner, it is therefore important to accurately measure air of different positions therein and to plan the ventilation and corresponding airflows accordingly. To accurately measure air of the different positions in the underground environment, measuring equipment is typically placed in the underground environment to measure the air. However, air measurements of some of the measuring equipment may have errors, where some errors may vary over time. These errors may negatively affect the ability to efficiently plan ventilation in the underground environment. Hence, there is an ongoing strive to improve air measurements of underground environments.

SUMMARY

An object of embodiments herein is to improve handling of air measurements in an underground environment.

According to a first aspect, a method for handling measurements of air in an underground environment is provided. The method comprises obtaining at least one first measurement of air at a first position. The at least one first measurement is measured by a mobile measuring equipment in the underground environment. The method further comprises obtaining at least one second measurement of air of a stationary measuring equipment that is located at a stationary position in the underground environment. The method further comprises, in response to determining that the first position is within a predefined range of the stationary position of the stationary measuring equipment, calibrating the at least one second measurement based on the at least one first measurement.

Since the at least one second measurement is calibrated based on the at least one first measurement when the first position is within the predefined range of the stationary position, more accurate measurements of air in the underground environment is achieved. This is since the mobile measuring equipment, due to its mobility, can travel and be calibrated more recently by an expert above-surface, and/or with one or more trusted sources. Therefore the at least one second measurement is calibrated to be more accurate when calibrated based on the at least one first measurement of the mobile measuring equipment. Furthermore, this allows for calibration of the at least one second measurement in a more efficient manner. This is since the mobile measuring equipment can, due to its mobility, travel to the stationary equipment where calibration is otherwise not feasible, e.g., as the stationary position may be a position difficult to reach with other calibration equipment. In some exemplary embodiments, the mobile equipment may be comprised in an autonomous vehicle or a remotely driven vehicle, thereby allowing the calibration to occur in places humans would be at risk and/or cause a performance degradation due to necessary safety measures.

According to an exemplary embodiment, calibrating the at least one second measurement may comprise adjusting the at least one second measurement based on a difference between the at least one second measurement and the at least one first measurement.

According to an exemplary embodiment, the method of the first aspect may further comprise calibrating a sensor of the stationary equipment by transmitting a calibration instruction to the stationary measuring equipment. In this way, the sensor may be calibrated to perform measurements more accurately.

According to an exemplary embodiment, the calibration instruction may be based on the at least one first measurement. In this way, the sensor may be calibrated to perform measurements more accurately as the sensor may be calibrated based on the at least one first measurement, and thereby any future measurements of the sensor will reflect the calibration accuracy of the at least one first measurement.

According to an exemplary embodiment, the calibration instruction may be based on a difference between the at least one first measurement and the at least one second measurement. In this way, the sensor may be calibrated to perform measurements more accurately as it is calibrated based on the difference between the at least one first measurement and the at least one second measurement and thereby any future measurements of the sensor may be normalized with respect to the at least one first measurement.

According to an exemplary embodiment, the calibration instruction may comprise a configuration or a configuration adjustment for the sensor of the stationary measuring equipment. In this way, a more flexible system is achieved as it may be possible to either configure the sensor with a new configuration or adjust an old configuration, e.g., with respect to the above-mentioned difference between the at least one first measurement and the at least one second measurement.

According to an exemplary embodiment, calibrating the at least one second measurement may be performed in response to assessing that there is a need to calibrate the at least one second measurement. In this way, calibration is only performed when necessary, thereby reducing calibration operations when unnecessary.

According to an exemplary embodiment, assessing that there is a need to calibrate the at least one second measurement may comprise determining that a difference between the at least one first measurement and at least a part of the at least one second measurement is above a threshold. In this way, calibration is only performed when necessary, thereby reducing calibration operations when unnecessary.

According to an exemplary embodiment, obtaining the at least one first measurement of the first position may comprise obtaining movement information of the mobile measuring equipment in the underground environment. In these exemplary embodiments estimating the first position may be performed by matching the movement information to one or more predefined paths of the underground environment. In this way, a more accurate calibration of the at least one second measurement is achieved. This is since the first position may be more accurately determined and hence, whether the first position is within the predefined range of the stationary position, is more accurately determined. It follows that a more accurate position will avoid calibration when the first position is outside the predefined range of the stationary position, and thereby calibration may only be performed when the mobile measuring equipment is close to the stationary measuring equipment, i.e. , within the predefined range.

According to one exemplary embodiment, determining a position of a mobile object, such as the first position of the mobile measuring equipment, may comprise: determining a movement path of the mobile object by recording movements of the mobile object; and comparing the determined movement path with possible movement paths for the mobile object in the underground environment.

High precision positioning systems in underground environments often rely on the mobile object being visible to an access point of an underground communications network, for example through signal communication between the mobile object and an access point. However, underground environments are unpredictable, ever-changing environments where both mountain walls, falling rock or large machines may come in the way for positioning signals. Therefore, positioning of the mobile object by determining a movement path and comparing it to possible movement paths is a more robust method to position the mobile object. This is at least because recording movements of the mobile object does not rely on connection to an access point. If connection to a communications network is unavailable, the recorded movements may be stored locally, and the comparison may be performed when connection is reinstated. Furthermore, comparing the determined movement path with possible movement paths does not rely on connection to an access point either, as the possible movement paths may be stored locally in the mining vehicle, and the comparison may thus be performed and stored locally. In this way, no position information is lost even when connection to an underground communications network is unavailable. As such, not only the current position and the associated parameter indicative of road quality may be communicated to the communications network when connection is available, but also positions and associated parameter measurements during the time connection was unavailable According to an exemplary embodiment, comparing the determined movement path with possible movement paths may comprise: comparing, through pattern matching, the determined movement path to known road segments of the underground environment, determining a road segment for which a matching error of the pattern matching is below a predetermined value, and determining that the position of the mobile object is on the determined road segment. In one exemplary embodiment, the known road segments may be provided as discretized patterns comprising nodes representing positions along the road segment, and wherein the pattern matching comprises: matching the nodes with the determined movement path of the mobile object.

According to an exemplary embodiment, the determined movement path may be a three-dimensional movement path. Thus, the determined movement path comprises information of whether the vehicle is mobile up or down in the underground environment.

According to a second aspect, a control unit configured to handle measurements of air in an underground environment is provided. The control unit is further configured to obtain at least one first measurement of air at a first position. The at least one first measurement is measured by a mobile measuring equipment in the underground environment. The control unit is further configured to obtain at least one second measurement of air of a stationary measuring equipment that is located at a stationary position in the underground environment. The control unit is further configured to, in response to determining that the first position is within a predefined range of the stationary position of the stationary measuring equipment, calibrate the at least one second measurement based on the at least one first measurement. Advantages and effects of the control unit are largely analogous to the advantages and effects of the method of the first aspect. Further, all embodiments of the control unit are applicable to and combinable with all embodiments of the method of the first aspect, and vice versa.

According to a third aspect, a computer program comprising instructions, which when executed by a processor, causes the processor to perform actions according to the first aspect. Advantages and effects of the computer program are largely analogous to the advantages and effects of the method of the first aspect. Further, all embodiments of the computer program are applicable to and combinable with all embodiments of the method of the first aspect, and vice versa.

According to a fourth aspect, a carrier comprising the computer program according to the fourth aspect, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium. Advantages and effects of the carrier are largely analogous to the advantages and effects of the method of the first aspect. Further, all embodiments of the carrier are applicable to and combinable with all embodiments of the method of the first aspect, and vice versa.

Further advantages and advantageous features of embodiments herein are disclosed in the following detailed description and in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of embodiments herein are described in more detail with reference to attached drawings in which:

Fig. 1 is a schematic block diagram illustrating a scenario according to exemplary embodiments herein.

Fig. 2 is a flowchart depicting a method according to exemplary embodiments herein.

Fig. 3 is a schematic block diagram illustrating exemplary embodiments herein.

Fig. 4 is a schematic block diagram illustrating exemplary embodiments herein.

Fig. 5 is a schematic block diagram illustrating exemplary embodiments herein.

Fig. 6 is a schematic block diagram illustrating exemplary embodiments herein.

Figs. 7a-b are line diagrams illustrating exemplary embodiments herein.

Figs. 8a-b are schematic block diagrams illustrating exemplary embodiments of a control unit.

DETAILED DESCRIPTION

Fig. 1 is a schematic overview depicting an underground environment 100 of exemplary embodiments herein. The underground environment 100 comprises various passages and paths surrounded by rock walls 80. Due to being underground and/or due to the rock walls 80, special conditions for wireless network connections are present. This is since radio waves may not easily travel through the rock walls 80 in the underground environment 100, as these are typically very dense and unsuitable for radio propagation. Radio signals in the underground environment 100 may instead bounce in the underground environment 100 in a manner much different from normal environments for wireless communications, and hence, normal approaches for network communication or positioning thereof may not apply.

The underground environment 100 may comprises one or more radio access points 31, 32, 33, 34 forming at least part of a communications network, e.g. connected to the Internet and/or any other suitable network. The one or more radio access points may comprise a first radio access point 31, a second radio access point 32, a third radio access point 33, and a fourth radio access point 34. While these four radio access points are depicted, the one or more radio access points may also comprise more than four radio access points. The one or more radio access points 31, 32, 33, 34 provide network connections to wireless devices in the underground environment 100. The one or more radio access points 31, 32, 33, 34 may be interconnected in any suitable manner, e.g. by switches and cables, and may also be connected to servers, base stations, and/or other networks. The one or more radio access points 31 , 32, 33, 34 may use the same or different Radio Access Technology (RAT). As an example, the one or more radio access points 31, 32, 33, 34 may provide network connections over radio using any one or more suitable RAT such as e.g. any one or more out of Long Term Evolution (LTE), Fifth Generation New Radio (5G NR), Wi-Fi, Worldwide Interoperability for Microwave Access (WiMAX), Bluetooth, Bluetooth Low Energy (BLE). One or more respective positions of the one or more radio access points 31, 32, 33, 34 may be static/ predetermined and/or obtainable by querying the one or more radio access points 31 , 32, 33, 34 and/or a central server. The one or more radio access points 31, 32, 33, 34 may comprise any suitable network node for providing the above-mentioned RATs, e.g., such as any one or more out of: a base station, an eNodeB (eNB), a gNodeB (gNB), a router, a repeater, etc.

In the underground environment 100, one or more mobile stationary equipment operates such as a stationary measuring equipment 30. The stationary measuring equipment 30 may be any suitable measuring equipment for measuring air in the underground environment 100. The stationary measuring equipment 30 is arranged at a stationary position within the underground environment 100. As an example, the stationary measuring equipment 30 may be arranged at a location which may be hard to reach for a human, and/or may be at a location which is associated with a production degradation when a human operator needs to travel there, e.g., due to a need to stop production as vehicles may be within a range of the stationary position, etc. The stationary measuring equipment 30 may comprise or be connected to a communication device that may have wireless or wired capabilities e.g. for communicating actively with any one or more out of the one or more radio access points 31, 32, 33, 34, a stationary measuring equipment 30, a server, and/or a control unit 70 in any suitable manner. The communication device of the stationary measuring equipment 30 may be an active device, e.g., capable of transmitting and receiving radio from the one or more radio access points 31, 32, 33, 34. Additionally, the communication device of the stationary measuring equipment 30 may comprise a passive device, e.g., a radio frequency tag, capable of being measured by other wireless devices and/or the one or more radio access points 31 , 32, 33, 34. The stationary measuring equipment 30 may be able to measure air at one or more positions. Each measurement may be time-stamped. The measurements of the stationary measuring equipment 30 may be logged at the stationary measuring equipment 30 and/or transmitted to an external unit such as a server or a control unit.

In the underground environment, one or more mobile measuring equipment operates such as a mobile measuring equipment 20. The mobile measuring equipment 20 may be any suitable mobile measuring equipment for measuring air in the underground environment 100. The mobile measuring equipment 20 may be attached to a vehicle 10 but may in some scenarios also be carried by a human. The vehicle 10 may in some exemplary embodiments be autonomous, semi-autonomous, or remotely controlled. The mobile measuring equipment 20 may comprise or be connected to a wireless device that may have wireless capabilities e.g. for communicating actively and/or passively with any one or more out of the one or more radio access points 31 , 32, 33, 34, a stationary measuring equipment 30, and/or a control unit 70. The wireless device of the mobile measuring equipment 20 may be an active device, e.g., capable of transmitting and receiving radio from the one or more radio access points 31, 32, 33, 34. The wireless device of the mobile measuring equipment 20 may comprise a passive device, e.g., a radio frequency tag, capable of being measured by other wireless devices and/or the one or more radio access points 31, 32, 33, 34. The mobile measuring equipment 20 may be able to measure air at one or more positions. Each measurement may be time-stamped. The measurements of the mobile measuring equipment 20 may be logged at the mobile measuring equipment 20 and/or transmitted to an external unit such as a server or a control unit.

In the underground environment 100, one or more ventilation equipment may be arranged, such as a ventilation equipment 90. The ventilation equipment 90 may be any suitable ventilation equipment for controlling a ventilation in the underground environment 100. For example, the ventilation equipment 90 may control where in the underground environment 100 to pump air and at what time periods. For example, the ventilation equipment 90 may use air measurements from stationary and/or mobile measuring equipment to improve an airflow in the underground environment 100.

Exemplary embodiments herein relate to handling measurements of air in the underground environment 100. This is performed by the mobile measuring equipment 20 performing at least one first measurement of air at a first position. Furthermore the stationary measuring equipment 30 performs at least one second measurement of air. Since the stationary equipment cannot easily be calibrated that often when being positioned in the underground environment, the at least one second measurement may comprise errors and may be in need of calibration with an accurate measurement. Hence, embodiment herein determines that when the first position is within a predefined range 40 of the stationary measuring equipment 30, the at least one second measurement is calibrated based on the at least one first measurement. This may mean that the at least one second measurement is normalized with respect to the at least one first measurement. The at least one first measurement may be measured during a first time period. The at least one second measurement may comprise measurements before and/or after the first time period. I.e. the calibration may be made with respect to the first time periods but may be used for measurements in the at least one second measurement already obtained before the first time period and/or for measurement(s) in the at least one second measurement obtained after the first time period.

When the at least one second measurement is calibrated, the ventilation equipment 90 may be controlled, e.g., to improve an airflow in the underground environment 100 at least partially based on the at least one second measurement.

To perform the exemplary embodiments herein, it may be needed to determine the first position of the mobile measuring equipment 20 in any suitable manner, for example, by determining the first position using radio signalling between the one or more radio access points 31 , 32, 33, 34 and the wireless device of the of the mobile measuring equipment 20 and/or signalling between the communication device of the stationary measuring equipment 30 and the wireless device of the of the mobile measuring equipment 20. Any combination of methods for determining the first position may be possible, some which will be explained in exemplary embodiments herein. For any of the described exemplary embodiments herein, it may be assumed that the first position and/or the stationary position may be with respect to a spatial representation of the underground environment 100, e.g., a map, which spatial representation may be obtained from a server dynamically and/or which spatial representation may be predefined. For some exemplary embodiments herein, it may be enough to determine the first position with a low accuracy, e.g., just that the first position is within the range of the stationary position. This may for example be done by measuring a signal strength of radio transmitted by the wireless device of the mobile measuring equipment 20.

Exemplary embodiments herein may be performed by any suitable control unit such as a control unit 70. The control unit 70 may form a system with the mobile measuring equipment 20 and/or the stationary measuring equipment 30. The control unit 70 may be located in any suitable location. For example, the control unit 70 may be located in the underground environment 100, or at a remote location, e.g. above ground. The control unit 70 may be part of a server but may also be part of the mobile measuring equipment 20 and/or part of the vehicle 10, e.g. carrying the mobile measuring equipment 20. The control unit 70 may also be co-located with any one of the radio access points 31, 32, 33, 34. Typically, the control unit 70 may communicate using a communications network which comprises the one or more radio access points 31 , 32, 33, 34. The control unit 70 may be communicatively coupled with the mobile measuring equipment 20 and the stationary measuring equipment 30 in any suitable manner, e.g., by communicating directly with the mobile measuring equipment 20 and the stationary measuring equipment 30 using the one or more radio access points 31, 32, 33, 34. When the control unit 70 is part of the mobile measuring equipment 20 and/or part of the vehicle 10, and when the mobile measuring equipment 20 is within a predefined range of the stationary position, then the mobile measuring equipment 20 and the stationary measuring equipment 30 may be able to communicate directly over radio, e.g., by using the wireless device of the mobile measuring equipment 20 and the communication device of the stationary measuring equipment 30. Therefore, the control unit 70 may be configured to obtain at least one first measurement from the mobile measuring equipment 20, and obtain at least one second measurement from the stationary measuring equipment 30. The control unit 70 is further configured to calibrate the at least one second measurement abased on the at least one first measurement.

A number of exemplary embodiments will now be described, which exemplary embodiments may be used in any suitable combination.

Fig. 2 illustrates an example embodiment of a method for handling measurements of air in an underground environment 100. The method comprises the following actions, which actions may be performed in any suitable order.

Action 201. The method comprises obtaining at least one first measurement of air at a first position. The at least one first measurement is measured by a mobile measuring equipment 20 in the underground environment 100.

In some exemplary embodiments, the at least one first measurement comprises a property based on measuring air.

The at least one first measurement of air may comprise any suitable measurement of air. For example, the at least one first measurement of air may comprise any one or more out of: humidity, pressure, number of particles, density of particles, composition of the air, e.g., what gases are in the air, and/or a temperature of the air. Obtaining the at least one first measurement may comprise obtaining the at least one first measurement directly from the mobile measuring equipment 20, e.g., when the control unit 70 performing the method is co-located. Alternatively, obtaining the at least one first measurement may comprise obtaining the at least one first measurement by wireless communication, e.g., by using any one or more out of the one or more radio access points 31 , 32, 33, 34.

The at least one first measurement may be obtained during a first time period.

The at least one first measurement may be time-stamped, i.e. a measurement in the at least one measurement may be paired with a time of when the measurement was performed.

The at least one first measurement may be location-stamped, i.e. a measurement in the at least one measurement may be paired with a location of where the measurement was performed.

Obtaining at least one first measurement of air at a first position may comprise obtaining the first position by any suitable means.

In some exemplary embodiments, obtaining the at least one first measurement of the first position comprises obtaining movement information of the mobile measuring equipment 20 in the underground environment 100. and estimating the first position by matching the movement information to one or more predefined paths of the underground environment 100. The movement information may be relative to at least one predefined position in the underground environment 100. The at least one predefined position may be a position that can be easily measured, e.g., by means of radio signalling, e.g., a beacon in the underground environment. Additionally or alternatively, the at least one predefined position may be a predefined start position, e.g., of the vehicle 10.

Action 202. The method comprises obtaining at least one second measurement of air of a stationary measuring equipment 30 that is located at a stationary position in the underground environment 100.

In some exemplary embodiments, the at least one second measurement comprises a property based on measuring air.

The at least one second measurement of air may comprise any suitable measurement of air. For example, the at least one second measurement of air may comprise any one or more out of: humidity, pressure, number of particles, density of particles, composition of the air, e.g., what gases are in the air, and/or a temperature of the air. Obtaining the at least one second measurement may comprise obtaining the at least one second measurement by wireless communication, e.g., by using any one or more out of the one or more radio access points 31, 32, 33, 34 and/or by direct radio communication with between the wireless device of the mobile measuring equipment 20 and the communication device of the stationary measuring equipment 30.

The at least one second measurement may be obtained during a second time period. The second time period may be the same or different as the first time period. For example, the second time period may overlap or comprise the first time period. In other words, for some exemplary embodiments, the at least one second measurement may comprise measurements before and/or after measurements of the at least one first measurement.

The at least one second measurement may be time-stamped, i.e. a measurement in the at least one measurement may be paired with a time of when the measurement was performed.

The at least one second measurement may be location-stamped, i.e. a measurement in the at least one measurement may be paired with a location of where the measurement was performed.

Action 203. The method comprises determining that the first position is within the predefined range 40 of the stationary position of the stationary measuring equipment 30. Determining that the first position is within the predefined range of the stationary position may be performed in any suitable manner.

The stationary position and/or the predefined range 40 may be predetermined. Hence, determining that the first position is within the predefined range 40 of the stationary position of the stationary measuring equipment 30 may either comprise determining a range between the first position and the stationary position, independently of the absolute position of the first position, or may comprise determining the first position and comparing with the stationary position to determine whether or not the first position is within the predefined range 40 of the stationary position.

In one example, when the mobile measuring equipment 20 is comprised in the vehicle 10, a positioning system of the vehicle 10 may determine the first position, e.g., and transmit the first position to the control unit 70. The positioning system of the vehicle 10 may use sensors to scan where the vehicle 10 is in the underground environment and may match a scanned environment with a map to determine the first position. Additionally or alternatively, determining the first position may comprise determining the first position based on radio communication performed with the wireless device of the mobile measuring equipment 20, e.g., by using radio signalling between the wireless device of the mobile measuring equipment 20 and any one or more out of the one or more radio access points 31 , 32, 33, 34 and/or by direct radio communication between the wireless device of the mobile measuring equipment 20 and the communication device stationary measuring equipment 30.

In some exemplary embodiments herein, determining that the first position is within the predefined range 40 of the stationary position of the stationary measuring equipment 30 may comprise determining that a radio signalling between the wireless device of the mobile measuring equipment 20 and the communication device stationary measuring equipment 30 is of high enough signal strength.

Action 204. In some exemplary embodiments, the method comprises assessing that there is a need to calibrate the at least one second measurement. Assessing that there is a need to calibrate the at least one second measurement may comprise determining that there is at least a risk that the at least one second measurement is not calibrated.

In some exemplary embodiments, assessing that there is a need to calibrate the at least one second measurement may comprise determining that the at least one second measurement and/or a sensor of the stationary measuring equipment 30 is, according to a time plan for calibration, due for calibration, i.e. a first time threshold for calibration may have been passed.

In some exemplary embodiments, assessing that there is a need to calibrate the at least one second measurement may comprise determining that the at least one second measurement is older than the at least one first measurement by at least a second time threshold.

In some exemplary embodiments, assessing that there is a need to calibrate the at least one second measurement comprises determining that a difference between the at least one first measurement and at least a part of the at least one second measurement is above a threshold.

Action 205. The method comprises, in response to determining, that the first position is within a predefined range 40 of the stationary position of the stationary measuring equipment 30, calibrating the at least one second measurement based on the at least one first measurement.

In some exemplary embodiments, calibrating the at least one second measurement comprises adjusting the at least one second measurement based on a difference between the at least one second measurement and the at least one first measurement. In other words , calibrating the at least one second measurement may comprise normalizing the at least one second measurement based on the at least one first measurement.

When the at least one second measurement is calibrated, any new measurement measured by the stationary measuring equipment 30 may further be part of the at least one second measurement, and calibrated with respect to the at least one first measurement.

In some exemplary embodiments, calibrating the at least one second measurement is performed based on an average value of the at least one first measurement.

In some exemplary embodiments, calibrating the at least one second measurement is performed in response to assessing that there is a need to calibrate the at least one second measurement, e.g., as in action 204.

Action 206. In some exemplary embodiments, the method comprises calibrating a sensor of the stationary equipment 30 by transmitting a calibration instruction to the stationary measuring equipment 30.

In this way, the sensor of the stationary equipment 30 may further perform measurements, e.g., as part of the at least one second measurements calibrated with respect to the at least one first measurement.

In some exemplary embodiments, the calibration instruction is based on the at least one first measurement.

In some exemplary embodiments, the calibration instruction is based on a difference between the at least one first measurement and the at least one second measurement.

In some exemplary embodiments, the calibration instruction comprises a configuration or a configuration adjustment for the sensor of the stationary measuring equipment 30.

In exemplary embodiments herein, any suitable combination of action 205 and action 206 is possible. For example, the at least one second measurement may be calibrated based on the at least one first measurement up until the first time period. Thereafter the sensor of the stationary equipment 30 may be calibrated such that accurate measurements can be measured by the sensor of the stationary equipment 30, e.g., as part of the at least one second measurement.

In some exemplary embodiments, calibrating the sensor of the stationary equipment 30 is performed in response to assessing that there is a need to calibrate the at least one second measurement, e.g., as in action 204.

Action 207. In some exemplary embodiments, the method comprises assessing an air condition in at least a part of the underground environment 100 based on the calibrated at least one second measurement. The air condition may be an air condition of a part of an area comprising the first position and/or the stationary position.

Action 208. In some exemplary embodiments, the method comprises determining at least one control parameter of the ventilation equipment 90 based on the assessed air condition in the at least part of the underground environment 100. For example, if the air condition indicates that there are too many particles in the air, e.g., more than a threshold, e.g., according to the at least one second measurement, the control parameter may indicate to increase an air flow in the area of the air condition.

Action 209. In some exemplary embodiments, the method comprises controlling the ventilation equipment 90 based on the at least one control parameter. Controlling the ventilation equipment 90 based on the at least one control parameter may comprise increasing and/or decreasing an airflow for at least one area in the underground environment 100.

Fig. 3 illustrates an example scenario of determining the first position, e.g., as in action 201 and/or 205. Determining the first position, may comprise one or more radio positioning estimations. The one or more radio positioning estimations may respectively be estimated using one or more different radio positioning services with the one or more radio access points 31 , 32, 33, 34. As example, the one or more radio access points 31, 32, 33, 34 may comprise any of: one or more BLE access points, one or more Wi-Fi access points, one or more LTE access points, one or more NR access points, or any combination thereof. In this example scenario, the one or more radio positioning estimations may be estimated based on:

- at least one first radio signal 301 transmitted between the first radio access point 31 and the wireless device of the mobile measuring equipment 20,

- at least one second radio signal 302 transmitted between the second radio access point 32 and the wireless device of the mobile measuring equipment 20

- at least one third radio signal 303 transmitted between the third radio access point 31 and the wireless device of the mobile measuring equipment 20, and

- at least one fourth radio signal 304 transmitted between the fourth radio access point 31 the wireless device of the mobile measuring equipment 20.

The first position may be determined, based on any one or more of the transmitted radio signals 301-304 to be a distance from the respective radio access point. The one or more position estimations may be used independently or in combination, e.g. for triangulation and/or trilateration. Trilateration as used herein may mean an estimating process comprising determining distances to multiple radio access points out of the one or more radio access points 31, 32, 33, 34, e.g. using a signal strength, and derive a position estimation of the wireless device of the mobile measuring equipment 20.

Triangulation as used herein may mean an estimating process comprising obtaining at least one distance between at least two radio access points of the one or more radio access points 31 , 32, 33 ,34, e.g. predetermined; determining distances from the wireless device of the mobile measuring equipment 20 and the at least two radio access points, e.g. using a signal strength, and derive a position estimation of the wireless device of the mobile measuring equipment 20

The one or more radio positioning estimations may be performed by the respective radio access points 31, 32, 33, 34, and/or the wireless device of the mobile measuring equipment 20. Any one or more out of the radio access points 31 , 32, 33, 34 may use any suitable RAT, e.g., different or same from other radio access points in the one or more radio access points. Alternatively, the information of the transmitted radio signals, e.g. measured signal strength and/or signal quality, may be transmitted to the control unit 70 which may perform the one or more radio positioning estimations. The radio signals 301, 302, 303, 304 may have differing qualities due to having different signal strengths and/or signal qualities, wherein higher signal strength and/or signal quality may increase indicated quality. Furthermore, the radio signals 301, 302, 302, 304 may be transmitted at different time periods, e.g. as different technologies may transmit using different periodicities, and as such, the newer radio positioning estimations may increase indicated qualities. Furthermore, different RATs may be associated with different precisions, e.g. any one or more out of: at least one RAT may utilize a higher frequency which is associated with a higher precision and/or accuracy in estimating positions but may instead be less robust, at least one RAT may be associated with a high precision and/or accuracy for one or more specific area locations, at least one RAT may be associated with a poor precision and/or accuracy for one or more specific area locations, at least one RAT may be associated with a precision and/or accuracy based on previous measurements. The qualities may be weighted due to many different configurations and contexts. This means that the lowest signal strength of the radio signals 301 , 302, 303, 304, may in some scenarios be associated with a radio positioning estimation of highest quality if e.g. the radio positioning estimation also has the most recent radio positioning estimations and has the highest precision. Likewise, the radio positioning estimation of the lowest precision may in some scenarios be associated with a radio positioning estimation of highest quality, for example if the radio positioning estimation is the most recent of the radio positioning estimations and has a high quality signal strength. The term high quality signal strength may for example mean that the signal strength is over a threshold. The threshold may be that the signal strength is measurable, that it is over a set value, over a dynamic threshold that is statistically defined etc.

Fig. 4 illustrates an example scenario of determining the first position, e.g., as in action 201 and/or 205 at least partially based on at least one position estimation of the wireless device of the mobile measuring equipment 20 estimated by the stationary measuring equipment 30. The stationary measuring equipment 30 may use its communication device to estimate the first position of the mobile measuring equipment 20 by means of a radio signal 401 transmitted between the wireless device of the mobile measuring equipment 20 and the communication device of stationary measuring equipment 30. The quality of the position estimated by the stationary measuring equipment 30 may be based on a signal strength and/or a signal quality of the transmitted radio signal 401. The position estimation and associated quality may be transmitted to the control unit 70, e.g. via the radio access points 31 , 32, 33, 34. The stationary position of the stationary measuring equipment 30 may be predefined or transmitted to the control unit 70.

Fig. 5 illustrates an example scenario wherein determining the first position, e.g., as in action 201 or 205 comprises using a former position 501 of the wireless device of the mobile measuring equipment 20 and a movement 502 of the wireless device of the mobile measuring equipment 20. The former position 501 and the movement 502 may respectively be the movement information and predefined position of actions 201. The former position 501 may be determined in any suitable manner, e.g. as in action 201 above or set by a user. The former position may also be determined above ground, e.g. by GPS before the wireless device of the mobile measuring equipment 20 moves underground. The movement 502 may indicate a path travelled by the wireless device of the mobile measuring equipment 20. When the mobile measuring equipment 20 is part of the vehicle 10, the movement 502 may be determined by dead reckoning techniques by the use of sensors on the vehicle 10, e.g. by measuring how wheels of the vehicle 10 is moving. The quality of the determined first position may be determined based on estimating accumulated errors e.g. when measuring sensors for dead reckoning. In some exemplary embodiments, the first position is determined by matching the former position 501 and the movement 502 with a predefined set of paths of the underground environment 100. The predefined set of paths may be a map of the underground environment 100. This may be referred to as pattern matching positioning. The determined first position and e.g., associated quality may be transmitted to the control unit 70, e.g. via the radio access points 31 , 32, 33, 34.

Fig. 6 illustrates an example scenario wherein the first position is determined by matching a former position and a movement of the mobile measuring equipment 20 with a predefined set of paths of the underground environment 100. The predefined set of paths is in the example scenario represented by a plurality of nodes N1-N19, i.e. representing positions in the predefined set of paths. The nodes N1-N19 corresponds to positions in the underground environment 100. Based on the former position of the mobile measuring equipment 20 and the movement of the mobile measuring equipment 20, a pattern of nodes T1-T4 representing a tracked movement of the mobile measuring equipment 20 may be estimated. In this scenario, the first position of the mobile measuring equipment 20 may be estimated by pattern matching between a first pattern representing an object track 601 of a movement undertaken by the mobile measuring equipment 20 and a second pattern representing the underground environment 100 in which the tracked movement has been undertaken by the mobile measuring equipment 20. The object track 601 have an object Track Head (TH) 602 and a tail, the TH 602 represents a current position of the mobile measuring equipment 20. The current position may be the first position. The pattern representing the underground environment 100 may be a discretized pattern representing the underground environment 100. The predefined set of paths may represent a plurality of nodes representing positions in the predefined set of paths. Determining the current position of the mobile measuring equipment 20 may comprise any one or more out of:

- when a matching error 603 in a current position of the mobile measuring equipment 20 exceeds a first threshold, determining nodes N1 ,...Nn of a pattern representing the underground environment 100 for which pattern matching is to be carried out utilizing a non-pattern matching positioning method, e.g. any other position estimation/determination method of the described exemplary embodiments herein,

- when the matching error 603 in the current position of the mobile measuring equipment 20 is below the first threshold, determining one or more nodes N1 ,...Nn of the pattern representing the environment for which pattern matching is to be carried out based on one or more nodes N1 ,...Nn of the pattern representing the underground environment 100 previously determined and/or estimated to be the position of the mobile measuring equipment 20, and - estimating the current position of the mobile measuring equipment 20 as a node for which the pattern matching results in a matching error 603 below the first threshold.

For the position determination in the example scenario of Fig. 6, the quality of the position determination may correspond to, or be represented by the matching errors 603 and/or the matching error of the TH 602, e.g., an average of the errors 603.

In some exemplary embodiments only the movement is needed, the former position may only improve speed and/or accuracy of performing the matching.

As an alternative combinable with the example of Fig 6, according to one exemplary embodiment, determining the first position of the mobile measuring equipment 20, may comprise: determining a movement path of the mobile measuring equipment 20 by recording movements of the mobile measuring equipment 20; and comparing the determined movement path with possible movement paths for the mobile measuring equipment 20 in the underground environment 100.

High precision positioning systems in the underground environment 100 may rely on the mobile object being visible to an access point of an underground communications network, for example through signal communication between the wireless device of the mobile measuring equipment 20 and an access point, e.g., any one or more out of the radio access points 31, 32, 33, 34. However, underground environments, such as the underground environment 100, are unpredictable, ever-changing environments where both mountain walls, falling rock or large machines may come in the way for positioning signals. Therefore, positioning of the mobile measuring equipment 20 by determining a movement path and comparing it to possible movement paths is a more robust method to position the mobile measuring equipment 20, e.g., than alternative approaches. This is at least because recording movements of the mobile measuring equipment 20 may not rely on connection to an access point. If connection to a communications network is unavailable or partially unavailable, the recorded movements may be stored locally, and the comparison may be performed when connection is reinstated. Furthermore, comparing the determined movement path with possible movement paths does not rely on connection to an access point either, as the possible movement paths may be stored locally in the mining vehicle, and the comparison may thus be performed and stored locally. In this way, no position information is lost even when connection to an underground communications network is unavailable. As such, not only the current position and the associated parameter indicative of road quality may be communicated to the communications network when connection is available, but also positions and associated parameter measurements during the time connection was unavailable According to an exemplary embodiment, comparing the determined movement path with possible movement paths may comprise: comparing, through pattern matching, the determined movement path to predefined road segments of the underground environment 100, determining a road segment for which a matching error of the pattern matching is below a predetermined value, and determining that the position of the mobile measuring equipment 20 is on the determined road segment. In one exemplary embodiment, the predefined road segments may be provided as discretized patterns comprising nodes representing positions along the road segment, and wherein the pattern matching comprises: matching the nodes with the determined movement path of the mobile measuring equipment 20.

In some exemplary embodiments, determining the first position of the mobile measuring equipment 20 in the underground environment 100 is determined based on a selected position determination. The selected position determination is selected out of a plurality of position determinations based on quality indicators indicating respective qualities of the plurality of position determinations in the underground environment 100. The plurality of position determinations and respective quality indicators may be obtained in any suitable manner using available different positioning services, e.g. pattern matching of paths in the underground environment with known movements of the mobile measuring equipment 20, dead reckoning techniques, radio triangulation, trilateration, signal strength/quality indicating closeness to radio access point etc. As an example, the selected position determinations may be determining the first position as in any one or more out of the examples in Figs. 4-6. Positioning services as used herein may be any mechanism and/or methodology suitable for estimating a position in the underground environment 100.

Figs. 7a-b illustrates an example scenario of performing calibration, e.g., as in action 205. In Fig. 7a, the at least one first measurement, e.g., as obtained in action 201, is illustrated by a first line 701. The at least one second measurement, e.g., as obtained in action 202, is illustrated by a second line 702. The at least one first measurement may be obtained during a first time period 703, e.g., as in action 201. The at least one second measurement may be obtained during a second time period, e.g., as in action 202. The first time period is in this case a subset of the second time period. The second time period may be ongoing, e.g., from starting the stationary measuring equipment 30 until shutting down the stationary measuring equipment 30. In this example, assessing, e.g., as in action 204, that there is a need to calibrate the at least one second measurement comprises determining that a difference 704 between the at least one second measurement and at least a part of the at least one second measurement is above a threshold. In Fig. 7b, the at least one second measurement is calibrated, e.g., as in action 205, based on the difference 704. In the example scenario, the at least one second measurement may be adjusted by deducting the difference from the at least one second measurement. This is illustrated by an adjusted line 705 illustrating an adjusted at least one second measurement 705. It should be noted that that while the at least one second measurement is calibrated both before and/after the first time period 703. I.e. based on the difference 704, measurements before, during, and/or after the first time period 703 as part of the at least one second measurements may be calibrated.

To perform exemplary embodiments herein, e.g. the method according to actions 201-209 above, may be performed by the control unit 70. The control unit 70 may be arranged in a centralized location, e.g. as part of a server or a cloud service, or may be located in the mine, e.g. co-located with the mobile measuring equipment 20, e.g., in the vehicle 10. The control unit 70 is configured to handle measurements of air in the underground environment 100.

The control unit 70 may comprise an arrangement depicted in Figs. 8a and 8b. The control unit 70 may comprise an input and output interface 800 e.g. for communicating with the communication device of the stationary measuring equipment 30 and/or the radio access points 31 , 32, 33, 34.

The input and output interface 800 may comprise a wireless or wired receiver (not shown), a transceiver, one or more antennas, and/or a wired or wireless transmitter (not shown).

The control unit 70 is configured to, e.g. by means of an obtaining unit 801 , obtain at least one first measurement of air at a first position. The at least one first measurement is measured by a mobile measuring equipment 20 in the underground environment 100.

The control unit 70 is configured to, e.g. by means of the obtaining unit 801 , obtain at least one second measurement of air of a stationary measuring equipment 30 that is located at the stationary position in the underground environment 100.

The control unit 70 may further be configured to, e.g. by means of a determining unit 802, determine that the first position is within the predefined range 40 of the stationary position. The control unit 70 may further be configured to, e.g. by means of an assessing unit 803, assess that there is a need to calibrate the at least one second measurement.

The control unit 70 is configured to, e.g. by means of a calibration unit 804, in response to determining that the first position is within a predefined range of the stationary position of the stationary measuring equipment 30, calibrate the at least one second measurement based on the at least one first measurement.

The control unit 70 may further be configured to, e.g. by means of the calibration unit 804, calibrate a sensor of the stationary measuring equipment 30.

The control unit 70 may further be configured to, e.g. by means of the assessing unit 803, assess an air condition based on the at least one second measurement.

The control unit 70 may further be configured to, e.g. by means of the determining unit 802, determine a control parameter of the ventilation equipment 90 based on the assessed air condition.

The control unit 70 may further be configured to, e.g. by means of a controlling unit 805, control the ventilation equipment 90 based on the control parameter.

The exemplary embodiments herein may be implemented through one or more processors, such as a processor 860 of a processing circuitry in the control unit 70, depicted in Fig. 8a, together with a computer program 880 comprising instructions, which when executed by a processor, causes the processor to perform the functions and actions of the exemplary embodiments herein.

In some exemplary embodiments, a respective carrier 890 comprises the respective computer program 880, wherein the carrier 890 is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium. For example, one such carrier may be in the form of a CD ROM disc or a memory stick. The computer program 880 may furthermore be provided as pure program code on a server and downloaded to the control unit 70.

The control unit 70 may further comprise a memory 870 comprising one or more memory units. The memory 870 comprises instructions executable by the processor in the control unit 70. The memory 870 is arranged to be used to store e.g. information, indications, data, configurations, measurements, position estimations and/or determinations, quality indicators, and applications to perform the exemplary embodiments herein when being executed in the control unit 70.

Those skilled in the art will appreciate that the units in the control unit 70 described above may refer to a combination of analog and digital circuits, and/or one or more processors configured with software and/or firmware, e.g. stored in the control unit 70, that when executed by the respective one or more processors such as the processors described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application-Specific Integrated Circuitry (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a system-on-a-chip (SoC).

When using the word "comprise" or “comprising” it shall be interpreted as nonlimiting, i.e. meaning "consist at least of".

It will be appreciated that the foregoing description and the accompanying drawings represent non-limiting examples of the methods and apparatus taught herein. As such, the apparatus and techniques taught herein are not limited by the foregoing description and accompanying drawings. Instead, the exemplary embodiments herein are limited only by the following claims and their legal equivalents.

Claims

1. A method for handling measurements of air in an underground environment (100), the method comprising: obtaining (201) at least one first measurement of air at a first position, wherein the at least one first measurement is measured by a mobile measuring equipment (20) in the underground environment (100), obtaining (202) at least one second measurement of air of a stationary measuring equipment (30) that is located at a stationary position in the underground environment (100), in response to determining (203) that the first position is within a predefined range (40) of the stationary position of the stationary measuring equipment (30), calibrating (205) the at least one second measurement based on the at least one first measurement.

2. The method according to claim 1, wherein calibrating (205) the at least one second measurement comprises adjusting the at least one second measurement based on a difference between the at least one first measurement and the at least one second measurement.

3. The method according to any one of claims 1-2, further comprising calibrating (206) a sensor of the stationary equipment (30) by transmitting a calibration instruction to the stationary measuring equipment (30).

4. The method according to claim 3, wherein the calibration instruction is based on the at least one first measurement.

5. The method according to any one of claims 3-4, wherein the calibration instruction is based on a difference between the at least one first measurement and the at least one second measurement.

6. The method according to any one of claims 3-5, wherein the calibration instruction comprises a configuration or a configuration adjustment for the sensor of the stationary measuring equipment (30).

7. The method according to any one of claims 1-6, wherein calibrating (205) the at least one second measurement is performed in response to assessing (204) that there is a need to calibrate the at least one second measurement.

8. The method according to claim 7, wherein assessing (204) that there is a need to calibrate the at least one second measurement comprises determining that a difference between the at least one first measurement and at least a part of the at least one second measurement is above a threshold.

9. The method according to any one of claims 1-8, wherein obtaining (201) the at least one first measurement of the first position comprises obtaining movement information of the mobile measuring equipment (20) in the underground environment (100), and estimating the first position by matching the movement information to one or more predefined paths of the underground environment (100).

10. The method according to claim 9, wherein the movement information is relative to at least one predefined position in the underground environment (100).

11. The method according to any of claims 1-10, wherein the at least one first measurement and the at least one second measurement respectively comprises a property based on measuring air.

12. The method according to claim 11, further comprising assessing (207) an air condition in at least a part of the underground environment (100) based on the calibrated at least one second measurement.

13. The method according to claim, 12 further comprising: determining (208) at least one control parameter of a ventilation equipment (90) based on the assessed air condition in the at least part of the underground environment (100), and controlling (209) the ventilation equipment (90) based on the at least one control parameter.

14. The method according to claim 13, wherein controlling (209) the ventilation equipment (90) based on the at least one control parameter comprises increasing and/or decreasing an airflow for at least one area in the underground environment (100). A control unit (70) configured to handle measurements of air in an underground environment (100), the control unit (70) is further configured to: obtain at least one first measurement of air at a first position, wherein the at least one first measurement is measured by a mobile measuring equipment (20) in the underground environment (100), obtain at least one second measurement of air of a stationary measuring equipment (30) that is located at a stationary position in the underground environment (100), in response to determining that the first position is within a predefined range of the stationary position of the stationary measuring equipment (30), calibrate the at least one second measurement based on the at least one first measurement. The control unit (70) according to claim 15, wherein the control unit (70) is further configured to perform any one out of claims 2-14. A computer program comprising instructions, which when executed by a processor, causes the processor to perform actions according to any of the claims 1-14. A carrier comprising the computer program of claim 17, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer-readable storage medium.