Underground worksite vehicle positioning control

Abstract

According to an example aspect of the present invention, there is provided a method, comprising: defining first confidence level information for position information by a satellite based first positioning source of a vehicle at a worksite comprising an underground tunnel system, defining second confidence level information for position information by a second positioning source configured to position the vehicle based on environment scanning, selecting a positioning correction source for the vehicle on the basis of the first confidence level information and the second confidence level information, and applying the selected positioning correction source for correcting dead- reckoning based positioning for the vehicle.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to positioning of vehicles, and inparticular to vehicles operating at worksites comprising an underground tunnelportion and a surface portion.BACKGROUND OF THE INVENTION

[0002] Mining or construction excavation worksites, such as hard rock or softrock mines, may comprise areas for automated operation of mobile vehicles, hereinreferred to as vehicles. A vehicle may be an unmanned, e.g. remotely controlledfrom a control room, or a manned vehicle, i.e. operated by an operator in a cabin ofthe mobile vehicle. An automated vehicle operating in an automatic mode mayoperate independently without external control but may be taken under externalcontrol at certain operation areas or conditions, such as during states ofemergencies.

[0003] Vehicles may comprise one or more sensors for scanning environmentof the vehicle, to detect obstacles and / or tunnel wall surface, for example. Suchsensors, such as two-dimensional laser scanners, may be referred to as environmentscanning sensors. Position tracking may be arranged particularly in undergroundmines on the basis of scanning data from the sensor(s) and a predefinedenvironmental model. WO2015106799 discloses a system for scanningsurroundings of a vehicle for producing data to determining position and orientationof the vehicle. The vehicle is provided with a reference point cloud data of the mine.The control unit is configured to match second point cloud data produced by ascanning device of the vehicle to the reference point cloud data in order to determineposition data of the vehicle.

[0004] US2017122741 discloses a construction machine control systemcomprising a position measurement unit that specifies position of the constructionmachine by comparing detection result of a non-contact sensor and map informationwhen a determination unit determines that the error in the position detected by aposition detection unit exceeds the predetermined error.SUMMARY OF THE INVENTION

[0005] The invention is defined by the features of the independent claims.Some specific embodiments are defined in the dependent claims.

[0006] According to a first aspect of the present invention, there is providedan apparatus, being configured to or comprising means configured for performingat least:defining first confidence level information for position information by asatellite based first positioning source of a vehicle at a worksite comprising anunderground tunnel system, defining second confidence level information forposition information by a second positioning source configured to position thevehicle based on environment scanning, selecting a positioning correction sourcefor the vehicle on the basis of the first confidence level information and the secondconfidence level information, and applying the selected positioning correctionsource for correcting dead-reckoning based positioning for the vehicle.

[0007] According to a second aspect of the present invention, there isprovided a method for controlling autonomous operation of a vehicle, comprising:defining first confidence level information for position information by a satellitebased first positioning source of a vehicle at a worksite comprising an undergroundtunnel system, defining second confidence level information for positioninformation by a second positioning source configured to position the vehicle basedon environment scanning, selecting a positioning correction source for the vehicleon the basis of the first confidence level information and the second confidencelevel information, and applying the selected positioning correction source forcorrecting dead-reckoning based positioning for the vehicle.

[0008] According to a third aspect, there is provided an apparatus comprisingat least one processor, at least one memory including computer program code, theat least one memory and the computer program code being configured to, with theat least one procesor core, provide the means for the apparatus and / or cause theapparatus at least to perform the method or an embodiment of the method.

[0009] According to a fourth aspect, there is provided a computer program,a computer program product or (a non-tangible) computer-readable mediumcomprising computer program code for, when executed in a data processingapparatus, to cause the apparatus to perform the method or an embodiment thereof.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIGURE 1 illustrates an example of a vehicle at a worksitecomprising an underground tunnel system;

[0011] FIGURE 2 illustrates a method according to at least someembodiments;

[0012] FIGURE 3 illustrates control architecture for controlling positioningaccording to some embodiments;

[0013] FIGURE 4 illustrates GPS error estimation;

[0014] FIGURE 5 illustrates a top view example of a vehicle and a worksiteportion; and

[0015] FIGURE 6 illustrates an example apparatus capable of supporting atleast some embodiments.EMBODIMENTS

[0016] Figure 1 illustrates a simplified example of a worksite 1, in the presentexample comprising a surface portion 2 and an underground (tunnel) portion 3. Theworksite may comprise an ore mine or a construction site, such as a railway or roadtunnel site.

[0017] A vehicle 10 may operate at the worksite 1 and drive between thesurface portion 2 and the underground portion 3. An area in which the tunnel endsand surface portion starts may be a (underground-surface) transition area. Thevehicle is in the present example a loader or a load and haul (LHD) vehiclecomprising a bucket 11 connected to a boom 12. The vehicle 10 may be anarticulated vehicle comprising two sections connected by a joint 13. However, itwill be appreciated that application of the presently disclosed features are notlimited to any particular type of vehicle which may be used at excavation worksites.Some other examples of such vehicle include lorries, dumpers, vans, mobile rockdrilling or milling rigs, or mobile reinforcement machines.

[0018] The vehicle 10 typically comprises a system 14 of pumps forgenerating hydraulic pressure for operating various parts of the machine, such aslifting the boom 12, turning the bucket 11, etc. The vehicle 10 may comprise oneor more other sources of energy, such as an accumulator, a hydrogen container, afuel tank, etc. The vehicle 10 may comprise a motor 15, such as a combustionengine or an electric motor. Power from the motor 15 may be provided by a crankshaft to front and / or rear wheels either directly or via a gear box.

[0019] The vehicle 10 comprises at least one control unit 20 configured tocontrol at least some functions and / or actuators of the vehicle. The control unit 20may comprise one or more computing units / processors executing computerprogram code stored in memory. The control unit may be connected to one or moreother control units of a control system of the vehicle, in some embodiments by acontroller area network (CAN) bus. The control unit may comprise or be connectedto a user interface with a display device as well as operator input interface forreceiving operator commands and information to the control unit.

[0020] The control unit 20 may be configured to control at least positioningcontrol related operations, but may be configured to perform also other controloperations, such as autonomous operation control. There may be one or more othercontrol units in the vehicle for controlling other operations. It is to be appreciatedthat the control unit 20 may be configured to perform at least some of the belowillustrated features, or a plurality of control units or controllers may be applied toperform these features. There may be further operations modules or functionsperformed by the control unit(s), e.g. an automatic positioning mode selectionfunction, at least one positioning unit / module / function, and / or a navigationfunction. It is to be appreciated that at least some of the control functionality couldbe implemented even outside the vehicle, e.g. at the worksite control system.

[0021] The vehicle 10 may comprise a wireless communication device, bywhich the control unit 20 and / or another unit of control system of the vehicle 10may establish a data transmission connection to another (second) control systemexternal to the vehicle by utilising a wireless connection provided by a base stationor access node 4. The communication device may thus be connected to acommunications system of the worksite, such as a wireless access systemcomprising a wireless local area network (WLAN) and / or a cellularcommunications network (e.g. a 4G, 5G or another generation cellular network).Non-terrestrial communication by a non-terrestrial transceiver may be configuredvia a satellite, e.g. by a Third Generation Partnership Project (3GPP) 5G based nonterrestrialnetwork (NTN).

[0022] The external control system may comprise or be connected to furthernetwork(s) and / or data processing system(s), such as a worksite managementsystem, a cloud service, a data analytics device / system, an intermediatecommunications network, such as the internet, etc. The system may comprise or beconnected to further device(s) or control unit(s), such as a handheld user unit, avehicle unit, a worksite management device / system, a remote control and / ormonitoring device / system, data analytics device / system, sensor system / device, etc.

[0023] The vehicle 10 may be unmanned. Thus, the user interface may beremote from the vehicle and the vehicle may be remotely controlled by an operatorin the tunnel, or in control room at the mine area, or even long distance away fromthe mine via communications network(s). A control unit outside the vehicle 10, forexample in the worksite management system may be configured to perform someof the below illustrated features. The vehicle 10 may be an automated vehicle,which in an autonomous operating or driving mode may operate / driveindependently without requiring continuous user control but which may be takenunder external control during states of emergencies, f or example. When the vehicleis in a manual driving mode, an operator drives the vehicle manually, by remotecontrol or locally at the vehicle by operator controls. The operator may set thevehicle into a (default) automatic driving mode in which the vehicle drivesautomatically a specified route, e.g. between a loading point and a dump shaft.Below disclosed positioning control related features may be applied when thevehicle 10 operates in the automatic driving mode, and / or for manually operatedvehicles or when the vehicle is in the manual operating mode.

[0024] The vehicle 10 comprises a positioning device or unit 30 for satellitebasedpositioning, which may also be referred to as satellite positioning unit, or asin the present example embodiments below, as Global Navigation Satellite System(GNSS) device. GNSS generally refers to satellite positioning systems that areoperating or planned, such as GPS, GLONASS (Russia), Galileo (European Union),BeiDou (China), the Indian Regional Navigation Satellite System (IRNSS), QZSS(Japan). When the vehicle 10 is positioned in the surface portion 2, the GNSS devicemay have a line of sight to a satellite 50, receive GNSS signal and define positionfor the vehicle based on the GNSS signal. The GNSS device and the wirelesscommunication device may be implemented in a single device.

[0025] In an embodiment, the positioning unit 30 includes a GPS receiverand an antenna for the GPS. When the position of the antenna is detected, theposition of the vehicle 10 is detected. The antenna receives a radio wave from aGPS satellite. The antenna outputs an electric signal based on the received radiowave to the GPS receiver which calculates the position of the antenna based on thesignal. It is to be noted that configuration of multiple antennas may be used, whichmay enable to calculate more accurate position information and also orientationinformation of the vehicle.

[0026] The vehicle 10 comprises one or more scanning units, or scanners 40,configured to perform scanning of environment around the vehicle. For example,the vehicle 10 may comprise a front scanner configured to scan environmenttowards normal forward driving direction A (and naturally to sides within reach ofthe scanner). The vehicle may also comprise a rear scanner configured to scan theenvironment towards direction opposite to A, i.e. backwards of the vehicle.

[0027] In some embodiments, the scanning results are applied to detectposition and orientation of the vehicle and one or more further elements thereof,such as the scanner 40 or the bucket 11. The control unit 20, or alternatively anothercontrol / computation unit in the vehicle, may compare operational scanned tunnelprofile data to reference profile data stored in an environment model and positionthe vehicle on the basis of finding a match in the environment model to position thevehicle and thus operate as scanning position source. The environment model maybe obtained based on scanning by (teach-)driving the vehicle or other type ofsurvey, for example.

[0028] In an embodiment, the scanner 40 may be a 2D scanner configured tomonitor tunnel walls at desired height, for example. In another embodiment, thescanner 40 is a 3D scanner, in which case 3D scanning data or point cloud data isproduced and applied for positioning the vehicle. Point cloud data generated on thebasis of scanning may be applied for generating and updating an environmentmodel, such as an underground tunnel model, which may be applied for positioningthe vehicle at the worksite. The vehicle 10 may comprise a simultaneouslocalization and mapping (SLAM) unit configured to both position the vehicle and(augment) map the environment on the basis of (2D or 3D) scanning informationwhile the vehicle is driving.

[0029] A control unit, e.g. the control unit 20, may execute a point cloudmatching functionality for matching operational (scanned) point cloud data (beingscanned by the scanner(s) 40) to environment model point cloud data, i.e. referencepoint cloud data. Position and direction of the scanning device and / or anotherinterest point of the vehicle, such as the (leading edge of the) bucket 11, may bedetermined in worksite coordinate system on the basis of the detected matchesbetween the operational point cloud data and the reference cloud data. The (2D or3D) scanner may be a laser scanner, but it is to be appreciated that other scannerconfigurations and sensor types, appropriate for vehicles at underground worksiteconditions may be applied instead of or in addition to laser sensors.

[0030] A driving plan, or a route plan, may define a route to be driven by thevehicle 10 and may be used as an input for automatic driving control of the vehicle.The plan may be generated offline and off-site, for example in an office, or onboard the vehicle e.g. by a teaching drive. The plan may define a start point, an endpoint, and a set of route points for the automatic drive. Such plan may be sent via awired or wireless connection to, or otherwise loaded to the vehicle, to a memory ofthe vehicle for access by the control unit 20 or another unit of the vehicle controllingnavigation of the vehicle along the route. In another embodiment, route points arenot pre-defined, but the mine vehicle defines path and steering control to avoidobstacles during autonomous driving towards a destination point.

[0031] In some embodiments positioning of the vehicle 10 is performed bydead-reckoning based positioning. The control unit 20 (or another control unit ofthe vehicle) may perform a dead reckoning algorithm configured to accumulate thevehicle's travelled distance and heading on the basis of input signal(s) indicative ofvehicle wheel rotation and relative heading. Dead-reckoning (DR) refers generallyto a method in which position of the vehicle 10 is estimated based on the orientationof the vehicle, for example, calculated from integration of the angular velocitymeasured by a gyro, and the moving distance, for example, integration of thevehicle speed calculated from the number of pulses of a tire pulse sensor and thetire diameter. It is to be appreciated that the system may comprise furtheroperational modules supplementing dead reckoning based position tracking, suchas a tyre slipping and / or wear compensation module.

[0032] Since error is accumulated by DR, the DR based position orpositioning may be corrected by another positioning source. While in the surfacesection 2, satellite 50 visibility enables to correct positioning of the vehicle 10 basedon position obtained by the GNSS device 30. While in the underground section 3,environment based scanning may be used to correct the DR based positioning, suchas the positioning based on the scanner 40 and the mapping of scanned tunnelprofile data from 2D or 3D scanner and the environment model.

[0033] At many worksites comprising underground and surface sections, afleet of vehicles needs to drive between these sections at challenging conditions,e.g. haul excavated rock to a surface unloading position, such as a crusher or a stockpile in paddock area. Transition (or portal) area between underground and surfacesections is often at a fairly steep slope, and stopping especially of a loaded vehicleis to be avoided. However, transitioning between underground and open airpositioning is challenging. One challenge is that transition to GNSS basedpositioning system is slow, in a worst case scenario even over 60 seconds. Whilethe vehicle is in the underground section, satellite data may get outdated, and reobtainingsatellite data upon again transitioning to the surface section 2 the may bevery slow. Even if the satellite data would be up-to-date, satellite signal reacquisitionis fairly slow, may take up to 15 seconds. It is very important to havereliable position information at all points of (underground-surface) transition areasto avoid collisions and stopping of the vehicle. A particular challenge is how andwhen to switch between underground and open-air positioning methods, which aretechnically very different.

[0034] There are now provided further improvements for positioning control,as further illustrated below.

[0035] Figure 2 illustrates a method for controlling positioning according tosome embodiments. The method may be performed by a vehicle and a controllingapparatus thereof, such as the vehicle 10, and by the control unit 20 thereof.

[0036] The method may comprise defining 210 first confidence levelinformation for position information by a satellite based first positioning source ofa vehicle at a worksite comprising an underground tunnel system. Block 220comprises defining second confidence level information for position informationby a second positioning source configured t o position the vehicle based onenvironment scanning. A positioning correction source is selected 230 for thevehicle on the basis of the first confidence level information and the secondconfidence level information. Reliability or quality of the positioning sources maythus be reviewed or compared on the basis of processing of the first and the secondconfidence level information. The selected positioning correction source is applied240 for correcting DR-based positioning for the vehicle.

[0037] When two position estimates are available, the one from the selectedpositioning correction source may then be used in or after block 240 for correctingthe DR-based positioning. The method may be continuously repeated, e.g. atpreconfigured time intervals, when there is need to correct the DR-based position,or even every time when new position estimates are available.

[0038] An optimal positioning source may be selected for correcting positingby DR, in particular when transitioning between surface section 2 and undergroundsection 3 of a worksite. Interruptions and stopping of an autonomously operatingvehicle due to non-available positioning correction may thus be minimized oravoided, improving production efficiency and affecting other vehicles at the sameroute. For example, switching due to reduced quality of current positioning sourceto another positioning source with very low confidence level may be avoided, butpositioning based on the current positioning source even at reduced confidencelevel may be temporarily allowed. Furthermore, additional infrastructure, such asGNSS signal repeaters at the transition areas may be avoided or minimized.

[0039] Comparable first confidence level value and second confidence scoreor level value may be generated on the basis of processing information explicitly orimplicitly indicative of position information accuracy or quality from the firstpositioning source and second positioning source, respectively. Such qualityinformation may comprise error estimate and / or correlation information (e.g.between measured position points and map position points), for example. Theprocessing may involve parameterization and / or weighting of input informationfrom the respective position source, such as an alysis of scanning resultsdistribution, some further examples being illustrated later. Positioning source andmethod specific confidence information / value generation algorithms andconfigurations may be configured e.g. to the control unit 20 to generate thecomparable confidence values.

[0040] Such comparable first and second confidence level values may begenerated in blocks 210 and 220, respectively. Alternatively, the comparable valuesare generated after block 220 on the basis of the first confidence level informationand the second confidence level information. The comparable confidence valuesenable comparison of current quality and confidence of the fundamentally verydifferent positioning sources may be compared in block 230.

[0041] In addition to or instead of (directly) comparing the confidencevalues, one or more further criterion or conditions and associated trigger orthreshold values may be applied in block 230 for changing from the currentlyapplied positioning correction source and selecting the source, some examplesbeing illustrated below. In a simple example, the positioning correction source ischanged in response to confidence level of currently applied positioning correctionsource meeting a position source change threshold value, i.e. is not reliable anymore. Thus, although the other positioning source does not either have a highreliability value, it may still be selected if the currently applied positioning sourceis too unreliable. However, if both first and second confidence values meet aposition source change threshold value, the vehicle may be permitted to proceedbased for a maximum allowed distance (without position correction), or a stopcommand may be issued.

[0042] One criterion may be amount of difference between the comparableconfidence level values. The first confidence level information and the secondconfidence level information are or are processed into comparable values. Thepositioning correction source may thus be selected 230 based on difference betweenthe first confidence level and the second confidence l evel. In a simple example,applied positioning correction source is changed from first source to the secondsource in response to the confidence level of the first source being at least 20% lessthan that of the second source.

[0043] However, when position estimate is available from both positioningsources and the overall positioning system applies same coordinate system for bothpositioning sources, such threshold value may be omitted or kept low, since it maynot be that problematic if the positioning correction method and source is changedback and forth. Due to the substantially differing characteristics of the associatedpositioning techniques, different criterion and threshold values may bepreconfigured for the positioning sources, and depending on if the currently appliedpositioning correction source is satellite-based or scanning-based. One or more(positioning correction) source selection configuration parameters may thus beapplied in block 230. One or more confidence configuration parameters affectingthe confidence level information definition may be applied in blocks 210 and 220.At least some of the parameters may be dynamically adapted.

[0044] Figure 3 illustrates an example of operational modules for controllingpositioning according to some example embodiments. A GNSS source 302 and ascanning (based) positioning source 304 are connected to a vehicle positioningcontrol module or unit 300, which may be implemented e.g. by the control unit 20of the vehicle 10. The control unit 300 comprises a GNSS confidence levelestimator 310, which may perform block 210 and define the confidence level forthe GNSS-based position source 302, such as a GPS receiver device. The controlunit 300 comprises a scanning confidence level estimator 312, which may performblock 220 and define the confidence level for the environment scanning basedposition source 304, such as a module or unit generating position estimate based onmapping operational scanned tunnel profile data from scanner(s) 40 to referenceprofile data stored in an environment model.

[0045] The estimators 310, 312 may provide their respective confidence levelvalues to a controller 320, which may be configured to operate at least as apositioning source selector performing block 2 30 and cause block 240. Thecontroller 320, or another module in the unit 300 or the vehicle 10, may host apositioning service or provider, configured to determine or receive DR-basedposition estimate based on information from DR-positioning source 330 and correctthe estimate on the basis of the selected positioning correction source. The controlunit 300, such as the controller 320 may be configured to define and / or accumulateDR-based positioning error. Alternatively, the DR-position source may accumulatethe error and indicate it to the controller 320. The controller 320 may be configuredto control DR-position correction and / or the correction source selection, in someembodiments based on the DR-positioning error reaching a correction threshold, ora preconfigured time period or travelled distance threshold since the previouscorrection being reached.

[0046] The positioning service may provide current position of the vehicle10 to one or more position consumers 340. A navigation / travel controller orautomatic driving controller of the vehicle may be the position informationconsumer 340, and apply the position information to generate steering commandsfor guiding the vehicle to a subsequent route point of a route plan. The vehicle mayalso comprise or be connected to other module(s), which may utilize the positioninformation, such as a specific collision avoidance control module, a task manager(may be configured to assign work tasks for a fleet of vehicles and update and / ormonitor task performance and status), a visualizer module (to generate at least somedisplay views for an operator (locally and / or remotely), a remote monitoring andcontrol module, etc.

[0047] In GPS embodiments, the positioning source 302 comprises a GPS(receiver) device which detects the position (the GPS position) of the vehicle 10 bydetecting the position (the GPS position) of an antenna of the GPS device. The firstconfidence level may be defined in block 210 by processing quality informationfrom the GPS device. Such quality information may be indicative of received signalquality, and may comprise error estimate information, for example.

[0048] The GPS device may detect a Fix solution, a Float solution, or a Singlesolution indicating the accuracy of the detected GPS position. This may be basedon the number of the positioning satellites from which the antenna has receivedinformation, for example, in the process of detecting the position of the antenna.

[0049] In simplified example scenarios, when the accuracy of the GPSposition is Fix solution, the vehicle 10 will select GPS position over the scanningbased position. Thus, full or 100% confidence may be assumed for GPS positionselected over the scanning based position, However, when the accuracy of the GPSposition is Float or Single solution, the methods may be compared by applying themethod of Figure 2. Scanning based position may thus often be selected, unless thescanning based position has high inaccuracy. The GPS receiver may output a signalindicating No solution when the GPS position cannot be measured. Thus, thescanning-based positioning update is used if position estimate with adequateconfidence level is available, or the DR-based positioning is continued (as long asallowed by DR positioning control configuration or until adequate position estimateis available from either positioning correction source.

[0050] The quality information from the GPS device may comprise real-timekinematic correction information and / or error variance information (which may bein an error ellipse). Error ellipse is related to the positioning confidence level orintegrity by horizontal position error (HPE) cumulative distribution function.

[0051] In some embodiments, the first and / or second confidence level isdefined 210, 220 by processing an error estimate for the associated positioninformation (by the first or second positioning source) on the basis of a targetpositioning accuracy parameter, such as comparing an error estimate value to oneor more error threshold or characterization values.

[0052] With reference to Figure 4, in an embodiment, the first confidencelevel information is defined based on computed probability of correct positionresiding within a target radius 402 from a reported position 400 (i.e. positionreported by the GPS device).

[0053] 1-sigma error estimate may be received from the GPS device,illustrated by ellipse 404. 1-sigma error may indicate that the correct position hassmaller error compared to the reported position within the ellipse in 67%probability, standard deviation. The first first confidence level information may bedefined by processing the received 1-sigma error estimate. GPS positioningconfidence may be computed based on parametrized target accuracy, illustrated inthe simple example of Figure 4 by Rtarget 402. Based on standard deviation, it ispossible to calculate the probability that the correct position is within the configuredtarget radius 402 from the reported position 400. This probability may be appliedas the position confidence level for GPS, or the final confidence level value may becalculated based on the probability.

[0054] The second positioning source 304 or the control unit 20, 300 may beconfigured to compare scanned tunnel profile data to reference profile data storedin an environment model (map data) and define information indicative of (amountor level of) correlation between them. In some embodiments, the second confidencelevel information is defined 220 on the basis of level of correlation between thescanned tunnel profile data (represented by measurement points) and the referenceprofile data (of the environment model). Some example embodiments are illustratedbelow.

[0055] Vehicle properties, including machine dimensions, dynamic vehiclestate parameters, including vehicle articulation angle, and DR-based positionestimate may be applied as input parameters in finding matching between points ofan environment model portion (based on the DR-based position estimate) andscanned measurement points.

[0056] In an example embodiment, an intensity (or correlation) table (oranother suitable form of information for processing) indicative of scanned tunnelprofile data correlation to environment model data may be generated (by thescanning positioning source 304 or the control unit 20, 300). Distance between a(scanned) measurement point and closest environment model point may bedetermined for each measurement point. This may be performed in lateral 2D planein respect of the vehicle, in x and y directions. Information based on such shortestdistances may be stored in the table, and the second position confidence levelinformation / value may be generated on the basis of processing the entries of thetable indicative of the correlation.In some embodiments, weighting is configured inthe system and applied in or after blocks 210 and 220. At least some of the positionestimate information received from the first positioning source and / or the secondpositioning source may be weighted, or the first and / or second confidence valuesare weighted. The positioning correction source selection may then be performedbased on the weighted values. A first confidence value may be defined by weightingposition estimate information received from the first positioning source by a firstweighting input. A second confidence value may be defined by weighting positionestimate information received from the second positioning source by a secondweighting input. The first confidence value and / or the second confidence valueis / are applied for the selecting of the applied positioning information source.

[0057] Figure 5 illustrates a top-view example of the vehicle 10 driving alonga route defined by a set of route points 500a, 500b, 500c. The broken line illustratesan example path and deviation from the route points caused by DR-positioningerror.

[0058] In some embodiments, the control unit 20 or the controller 320accumulates for DR-based positioning latitudinal error (in direction y) andlongitudinal error (direction x in the direction of driving) after reset at the previousposition correction while the vehicle 10 is moving. In an embodiment, thelongitudinal and / or latitudinal error is estimated on the basis of recent historicalerror correction to DR-based positioning by the scanning-based positioning, e.g.such historical error correction data recorded for a predetermined time or distance.Thus, positioning error estimation and / or associated threshold setting may beadapted based on amount of correction required at one or more earlier correctionevents, i.e. difference(s) between the DR-based position and scanning-basedposition.

[0059] The accumulated latitudinal and / or longitudinal error(s) may becompared to maximum allowed error threshold value(s), which may also be referredto or associated with safety margin for the vehicle. In response to a maximumallowed error threshold value(s) being exceeded, and if no position correction withadequate confidence level is available from either position correction source 302,304, the vehicle 10 may be stopped or speed further reduced. Monitoring of thelatitudinal error is particularly relevant in underground tunnels. For example, whenthe accumulated latitudinal error exceeds safety margin D, the vehicle may becontrolled to stop. The error threshold(s) applied may be configurable. In someembodiments, the error threshold(s) are automatically configured based on theenvironment traversed by the vehicle and / or properties of the vehicle. The errorthreshold(s) may be configured on the basis of the environment model, route model,and / or path traversed by the vehicle. In an example, width of the tunnel W isestimated on the basis of the environment model and the error threshold ET maydefine maximum allowed estimated vehicle distance from a wall and may bedefined:ET = W - (D + VW (vehicle width))

[0060] In some embodiments, time of the vehicle and / or distance travelledby the vehicle since the previous position update is monitored. The vehicle iscontrolled to stop in response to detecting that a maximum time or maximumdistance is reached.

[0061] In some embodiments, speed reduction for the vehicle 10 is controlledin response to both positioning sources 302, 304 indicating weak or weakeningconfidence, e.g. both the first and second confidence values meeting apreconfigured slowdown threshold value. For example, the control unit 20 mayreduce speed of the vehicle to a value in the range 2 to 10 km / h in such case. Thecontrol unit 20 may set a speed limit for the vehicle. The speed of the vehicle maybe reduced gradually to the associated value or range.

[0062] It is to be appreciated that various further features may be complementor differentiate at least some of the above-illustrated embodiments. For example,there may be further user interaction and / or automation functionality furtherfacilitating the operator to monitor the vehicle, select appropriate action toovercome an issue regarding lacking accurate position information, and control thevehicle.

[0063] In an embodiment, position of the vehicle 10 in the transition areamay be updated on the basis of an external location reference unit, if available. Thelocation reference unit may be a wireless signal emission unit at a tunnel wall or alocation tracking unit of another vehicle, for example. An RF tag, an access point,a visually readable code or another fixed unit, the location of which is accuratelyknown may serve as the location reference. Reference is also made to US7899599disclosing that such identifier may be applied to update dead reckoning basedlocation.

[0064] An electronic device comprising electronic circuitries may be anapparatus for realizing at least some embodiments illustrated above, such as themethod illustrated in connection with Figure 2 and features illustrated for thecontrol unit 20. The apparatus may be comprised in at least one computing deviceconnected to or integrated into a control system of the vehicle. Such control systemmay be an intelligent on-board control system controlling operation of various sub25systems of the vehicle, such as a hydraulic system, a motor, etc. Such controlsystems are often distributed and include many independent modules connected bya bus system of controller area network (CAN) nodes, for example.

[0065] Figure 6 illustrates a simplified example apparatus capable ofsupporting at least some embodiments of the present invention. Illustrated is adevice 60, which may be configured to carry out at least some of the aboveillustratedembodiments relating to positioning control. In some embodiments, thedevice 60 comprises or implements the control unit 20, or other module(s),functions and / or unit(s) for performing at least some of the above-illustratedembodiments.

[0066] Comprised in the device 60 is a processor 61, which may comprise,for example, a single- or multi-core processor. The processor 61 may comprisemore than one processor. The processor may comprise at least one application specificintegrated circuit, ASIC. The processor may comprise at least one fieldprogrammable gate array, FPGA. The processor may be configured, at least in partby computer instructions, to perform actions.

[0067] The device 60 may comprise memory 62. The memory may compriserandom-access memory and / or permanent memory. The memory may be at least inpart accessible to the processor 61. The memory may be at least in part comprisedin the processor 61. The memory may be at least in part external to the device 60but accessible to the device. The memory 62 may be means for storing information,such as parameters 64 affecting operations of the device. The parameter informationin particular may comprise parameter information affecting the positioning controlrelated features, such as threshold values.

[0068] The memory 62 may be a non-transitory computer readable mediumcomprising computer program code 63 including computer instructions that theprocessor 61 is configured to execute. When computer instructions configured tocause the processor to perform certain actions are stored in the memory, and thedevice in overall is configured to run under the direction of the processor usingcomputer instructions from the memory, the processor and / or its at least oneprocessing core may be considered to be configured to perform said certain actions.The processor may, together with the memory and computer program code, formmeans for performing at least some of the above-illustrated features in the device,such as the method of Figure 2.

[0069] The device 60 may comprise a communications unit 65 comprising atransmitter and / or a receiver. The transmitter and the receiver may be configured totransmit and receive, respectively, i.a. data and control commands within or outsidethe vehicle. The transmitter and / or receiver may be configured to operate inaccordance with global system for mobile communication, GSM, wideband codedivision multiple access, WCDMA, long term evolution, LTE, 3GPP new radioaccess technology (N-RAT), wireless local area network, WLAN, a non-terrestrialcommunication standard, and / or Ethernet standards, for example. The device 60may comprise a near-field communication, NFC, transceiver. The NFC transceivermay support at least one NFC technology, such as NFC, Bluetooth, or similartechnologies.

[0070] The device 60 may comprise or be connected to a UI. The UI maycomprise at least one of a display 66, a speaker, an input device 67 such as akeyboard, a joystick, a touchscreen, and / or a microphone. The UI may beconfigured to display views on the basis of above illustrated embodiments. A usermay operate the device and control at least some of above illustrated features. Insome embodiments, the user may control the vehicle 10 via the UI, for example tomanually drive the vehicle, operate a boom, change driving mode, change displayviews, modify parameters 64, etc.

[0071] The device 60 may further comprise and / or be connected to furtherunits, devices and systems, such as one or more sensor devices 68, such as thescanner(s) 40 or other sensor devices sensing environment of the device 60 orproperties of the vehicle, such wheel rotation or orientation changes.

[0072] The processor 61, the memory 62, the communications unit 65 andthe UI may be interconnected by electrical leads internal to the device 60 in amultitude of different ways. For example, each of the aforementioned devices maybe separately connected to a master bus internal to the device, to allow for thedevices to exchange information. However, as the skilled person will appreciate,this is only one example and depending on the embodiment various ways ofinterconnecting at least two of the aforementioned devices may be selected withoutdeparting from the scope of the present invention.

[0073] It is to be understood that the embodiments of the invention disclosedare not limited to the particular structures, process steps, or materials disclosedherein, but are extended to equivalents thereof as would be recognized by thoseordinarily skilled in the relevant arts. It should also be understood that terminologyemployed herein is used for the purpose of describing particular embodiments onlyand is not intended to be limiting.

[0074] References throughout this specification to one embodiment or anembodiment means that a particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodiment of thepresent invention. Thus, appearances of the phrases "in one embodiment" or "in anembodiment" in various places throughout this specification are not necessarily allreferring to the same embodiment.

[0075] As used herein, a plurality of items, elements, and / or materials maybe presented in a common list for convenience. However, these lists should beconstrued as though each member of the list is individually identified as a separateand unique member. Furthermore, the described features, items, elements, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

[0076] While the forgoing examples are illustrative of the principles of thepresent invention in one or more particular applications, it will be apparent to thoseof ordinary skill in the art that numerous modifications in form, usage and detailsof implementation can be made without the exercise of inventive faculty, andwithout departing from the principles and concepts of the invention. Accordingly,it is not intended that the invention be limited, except as by the claims set forthbelow.

[0077] The verbs "to comprise" and "to include" are used in this documentas open limitations that neither exclude nor require the existence of also un-recitedfeatures. The features recited in depending claims are mutually freely combinableunless otherwise explicitly stated. Furthermore, it is to be understood that the useof "a" or "an", that is, a singular form, throughout this document does not excludea plurality.

Claims

1. An apparatus comprising means configured for performing: - defining (210) first confidence level information for position information by a satellite based first positioning source (302) of a vehicle (10) at a worksite (1) comprising an underground tunnel system, - defining (220) second confidence level information for position information by a second positioning source (304) configured to position the vehicle based on environment scanning, - generating, on the basis of the first confidence level information and the second confidence level information, a first confidence level value and a second confidence level value, respectively; - selecting (230) a positioning correction source for the vehicle on the basis of the first confidence level value and the second confidence level value, and - applying (240) the selected positioning correction source for correcting dead-reckoning based positioning for the vehicle.

2. The apparatus of claim 1, wherein the means are configured for performing: defining a first confidence value on the basis of processing position estimate information from the first positioning source (302) and a second confidence value on the basis of processing position estimate information from the second positioning source (304), and comparing the first confidence value and the second confidence value for the selecting of the applied positioning information source.

3. The apparatus of claim 2, wherein the processing comprises weighting at least some of the position estimate information or the confidence values before selecting (230) the positioning correction source.

4. The apparatus of any preceding claim, wherein the means are configured to define (210) the first confidence level on the basis of quality information from a global navigation satellite system unit (302).

5. The apparatus of claim 4, wherein the means are configured to receive an error estimate from a global positioning system device and define (210) the first confidence level by processing the error estimate on the basis of a target positioning accuracy parameter.

6. The apparatus of claim 5, wherein the first confidence level information is defined (210) based on computed probability of correct position residing within a target radius from a reported position.

7. The apparatus of any preceding claim, wherein the second positioning source (304) is configured to compare scanned tunnel profile data to reference profile data stored in an environment model, and the means are configured to define the second confidence level information on the basis of level of correlation between the scanned tunnel profile data and the reference profile data.

8. The apparatus of any preceding claim, wherein the apparatus is a loading and / or hauling vehicle or a drilling rig configured to operate autonomously.

9. A method for controlling positioning of a vehicle (10) at a worksite (1) comprising an underground tunnel system, comprising: - defining (210) first confidence level information for position information by a satellite based first positioning source (302) of the vehicle, - defining (220) second confidence level information for position information by a second positioning source (304) configured to position the vehicle based on environment scanning, - generating, on the basis of the first confidence level information and the second confidence level information, a first confidence level value and a second confidence level value, respectively; - selecting (230) a positioning correction source for the vehicle on the basis of the first confidence level value and the second confidence level value, and - applying (240) the selected positioning correction source for correcting dead-reckoning based positioning for the vehicle.

10. The method of claim 9, further comprising: defining a first confidence value on the basis of processing position estimate information from the first positioning source (302) and a second confidence value on the basis of processing position estimate information from the second positioning source (304), and comparing the first confidence value and the second confidence value for the selecting of the applied positioning information source.

11. The method of claim 9 or 10, wherein the first confidence level is defined (210) on the basis of quality information from a global navigation satellite system unit (302).

12. The method of claim 11, wherein an error estimate is received from a global positioning system device and the first confidence level is defined (210) by processing the error estimate on the basis of a target positioning accuracy parameter.

13. The method of claim 12, wherein the first confidence level information is defined based on computed probability of correct position residing within a target radius from a reported position.

14. The method of any preceding claim, wherein the second positioning source (304) compares scanned tunnel profile data to reference profile data stored in an environment model, and the second confidence level information is defined (220) on the basis of level of correlation between the scanned tunnel profile data and the reference profile data.

15. A computer program comprising code for, when executed in a data processing apparatus (60), causing the method of any one of claims 9 to 14 to be performed.