SE1650608A1 - Method and control unit for a vehicle - Google Patents

Abstract

Method (400) and control unit (310) in a vehicle (100) for determining if a preceding vehicle. (130) is suitable for platooning. The method (400) comprises measuring (401) at least one parameter of a tail of the preceding vehicle (130) with a first sensor (110), of a first type; measuring (402) at least one parameter of the tail of the preceding vehicle (130) with a second sensor (120), of a second type; estimating (404) a probability value of the preceding vehicle (130) being suitable for platooning, based on the measured (401, 402) at least one parameter; and determining (405) that the preceding vehicle (130) is suitable for platooning when the determined (404) probability value exceeds a threshold value.(Publ. Fig. 1B)

Description

METHOD AND CONTROL UNIT FOR A VEHICLE TECHNICAL FIELD This document discloses a method and a control unit. More particularly, a method and acontrol unit are disclosed, for determining if a preceding vehicle is suitable for platooning.

BACKGROUND Grouping vehicles into platoons is an emerging technology, leading to reduced fuel con-sumption and increased capacity of the roads. A number of vehicles, e.g. 2-25 or more, maybe organised in a platoon or vehicle convoy, wherein the vehicles are driving in coordinationafter each other with only a small distance between the vehicles, such as some decimetresor some meters, e.g. up to about 20 meters (the inter-vehicular distance may be dependente.g. on vehicle velocity, vehicle weight, road topography, road condition, etc.). Thereby airresistance is reduced, which is important for reducing energy consumption, in particular forheavy duty vehicles such as trucks, busses and goods vehicles or other vehicles having alarge frontal area. ln principle it may be said that the shorter the distance is between thevehicles, the lower the air resistance becomes, which reduces energy consumption for thevehicle platoon.

The commercially available Adaptive Cruise Control (ACC) enables both of the above men-tioned techniques for reducing air drag (and fuel consumption) by utilising radar, lidar, and/or camera information and thereby allowing for reducing air drag when a fonNard vehicle ispresent; and staying closer to a forward vehicle which may reduce air drag due to the aero-dynamic effects.

Platooning brings a multitude of advantages, such as improved fuel economy due to reducedair resistance, and also reduced traffic congestion leading to increased capacity of the roadsand enhanced traffic flow, thereby bringing advantages also to other road users. On longdistance routes, vehicles could be mostly unattended whilst in following mode, giving thedriver an opportunity to rest and be well rested when leaving the platoon for the final desti-nation, which potentially leads to less traffic incidents. Further, it may not be required to stopthe vehicle in order for the driver to rest, leading to a reduced transportation time (this mayrequire modified law regulation concerning driving times, breaks and rest periods for driversof vehicles in a platoon).

However, although platooning is advantageous for the vehicle owner, the enumerated ad-vantages may not be achieved, either because an inappropriate vehicle is followed when anad-hoc platoon is assembled, or because the driver is unwilling to drive in a platoon formation and therefore never form any ad-hoc platoon, or form fewer ad-hoc platoons (or for shorterdistances) than it in reality would be possible. As the owner of heavy duty vehicles typicallynot is present during transportation, he/ she may not be aware of this situation. Thereby, lessfuel is saved than would have been possible.

The on-board systems in modern vehicles can monitor whether the radar is detecting anobject in front of the own vehicle and if the ACC is actively governing the vehicle. However,the type of vehicle that is being tracked, i.e. its characteristic properties, is not known andtherefore it becomes very difficult for the owner or a service provider, to determine whetherplatooning in fuel efficient circumstances have been conducted.

Document WO2013187834 presents a system for regulating vehicles in a vehicle train,wherein the vehicles are intercommunicating via wireless communication. lnformation rele-vant for determining the distance to keep between vehicles in the vehicle train is collectedby a leader vehicle of the vehicle train, and based on this information, the appropriate dis-tance is determined and sent to the respective follower vehicle in the vehicle train.

The system concerns regulation of inter-vehicle distances of an already formed vehicle train,not creation of an ad hoc vehicle train. Further, the system requires wireless communicationand extensive information exchange between the involved vehicles. However, many vehicleswhich per se are suitable for driving in a platoon are not configured for wireless communica-tion. Even in case the vehicle is configured for wireless communication, it may not want toshare information with any other vehicle which may belong to a competitor; thus it would bedesired to not be dependent on wireless communication when forming a vehicle train. lnaddition, the system requires a leader vehicle of the vehicle train to initiate the wireless com-munication. lt would be desired to instead develop a system where any arbitrary vehicle, notbelonging to any vehicle train could initiate the formation of an ad hoc vehicle train.

Document US6081756 relates to a vehicle running management system for a highway com-prising a lane for automatically driven vehicles, which vehicles are configured for wirelesscommunication. The system communicates with vehicles in the lane and detects any manu-ally driven vehicle, driving in the lane and provides information concerning those detectedmanually driven vehicles to any automatically driven vehicle, warning those vehicles for fol-lowing such vehicle too close.

The system does not concern creation of vehicle platoons. Further, the system is based onwireless communication, thereby suffering from the same disadvantages as already con-cluded above. Further, the system is directed towards warning automatically driven vehicles from manually driven vehicles, which may be driving in an unpredictable manner, such asswapping between lanes without using indicators, exceeding vehicle speed regulations,overtaking other vehicles in the inside lane, etc., so that they may keep a longer distance to manually driven vehicles.

Document US20050228588 illustrates a system for assisting a vehicle driver in positioningthe vehicle laterally on the road. The position of the vehicle is determined in relation to bound-aries of a lane in which it is driving. A vehicle in another neighbouring driving lane is detected,tracked and used for autonomous lateral positioning of the own vehicle.

The system does not concern neither creation nor driving management of vehicle platoons,but is focusing on lateral lane positioning of an individual vehicle.

Document WO2013165297 concerns a system for forming a platoon. The system identifiestwo vehicles for inclusion into the platoon. Based upon various vehicle characteristics suchas e.g.: vehicle model, vehicle size, vehicle weight, load size, load weight, etc., a decisionmay be made, whether the two vehicles are suitable for inclusion into a common platoon.The identification is made by a road side unit, wherein all calculations and computations areperformed.

The disclosed system requires an infrastructure with road side units comprising a multitudeof sensors for detecting the vehicles and categorise them. Such infrastructure is currentlynon-existing and expensive to create. The disclosed system thus appears very unrealistic,as heavy investments are required by the owner of the road, while the economic earnings ofthe platoon driving goes to the vehicle owners enabled to exploit the system. lt appears that further development is required for enabling and facilitating creation of vehicleplatoons and detecting vehicle drivers which are unwilling to drive in platoon formation, alsowhen suitable vehicles for platoon formation are available.

SUMMARY lt is therefore an object of this invention to solve at least some of the above problems andprovide improved vehicle platoon formation.

According to a first aspect of the invention, this objective is achieved by a method in a vehiclefor determining if a preceding vehicle is suitable for platooning. The method comprises meas-uring at least one parameter of a tail of the preceding vehicle with a first sensor, of a firsttype. Further, the method also comprises measuring at least one parameter of the tail of the preceding vehicle with a second sensor, of a second type. ln addition, the method furthercomprises estimating a probability value of the preceding vehicle being suitable for platoon-ing, based on the measured at least one parameter. The method furthermore comprisesdetermining that the preceding vehicle is suitable for platooning when the determined prob-ability value exceeds a threshold value.

According to a second aspect of the invention, this objective is achieved by a control unit ina vehicle for determining if a preceding vehicle is suitable for platooning. The control unit isconfigured to send a first control signal to a first sensor, of a first type, for measuring at leastone parameter of a tail of the preceding vehicle. Further the control unit is also configured tosend a second control signal to a second sensor, of a second type, for measuring at leastone parameter of the tail of the preceding vehicle. ln addition, the control unit is further con-figured to estimate a probability value of the preceding vehicle being suitable for platooning,based on the measured at least one parameter. The control unit is furthermore also config-ured to determine that the preceding vehicle is suitable for platooning when the determinedprobability value exceeds a threshold value.

Thanks to the described aspects, by collecting sensor data from two distinct sensors of dif-ferent types, such as e.g. a radar and a camera, concerning the size of the tail of the pre-ceding vehicle, a decision concerning whether the preceding vehicle is suitable for forminga platoon with the own vehicle could be made with high reliability. Further, by introducingand using a probability value of the preceding vehicle being suitable for platooning, basedon the measured parameters and a truth function, the reliability of the suitability detection isfurther enhanced.

Thereby, a service for monitoring how much each vehicle in a vehicle fleet is actually pla-tooning under favourable conditions is provided. Thereby the vehicle owner may detect ve-hicle drivers who are unwilling to form and drive in platoons; vehicle drivers who select inap-propriate other vehicles to form platoons with, etc. Thus educational measures may be takenfor informing those identified drivers about the advantages of platooning and how to selectappropriate vehicles for platooning. Furthermore, thanks to the disclosed solution, also au-tonomous vehicles are enabled to form a platoon with another vehicle, independently of anyhuman intervention. Yet another advantage of the disclosed method is that an ad hoc platoonmay be easily performed, also when the involved vehicles cannot intercommunicate wire- lessly with each other.

Further, statistics may be established based on the obtained information concerning per-centage of driving in/ out of platoons; how much fuel that is saved by platooning, etc. Therebya tool for improved vehicle platoon formation is provided.

Other advantages and additional novel features will become apparent from the subsequentdetailed description.

FIGURES Embodiments of the invention will now be described in further detail with reference to theaccompanying figures, in which: Figure 1A illustrates a side view of a vehicle according to an embodiment, and anothervehicle; Figure 1B illustrates a scenario with a vehicle driving behind another vehicle in front,according to an embodiment, seen from above; Figure 2A schematically illustrates a vehicle interior of a vehicle driving behind anothervehicle, according to an embodiment; Figure 2B schematically illustrates a vehicle interior of a vehicle driving behind anothervehicle, according to an embodiment; Figure 3 schematically illustrates a truth function according to an embodiment; Figure 4 is a flow chart illustrating an embodiment of the method; Figure 5 is an illustration depicting a system according to an embodiment.

DETAILED DESCRIPTION Embodiments of the invention described herein are defined as a control unit and a methodin a control unit, which may be put into practice in the embodiments described below. Theseembodiments may, however, be exemplified and realised in many different forms and arenot to be limited to the examples set forth herein; rather, these illustrative examples of em-bodiments are provided so that this disclosure will be thorough and complete.

Still other objects and features may become apparent from the following detailed description,considered in conjunction with the accompanying drawings. lt is to be understood, however,that the drawings are designed solely for purposes of illustration and not as a definition ofthe limits of the herein disclosed embodiments, for which reference is to be made to theappended claims. Further, the drawings are not necessarily drawn to scale and, unless oth- en/vise indicated, they are merely intended to conceptually illustrate the structures and pro-cedures described herein.

Figure 1A illustrates a vehicle 100, driving in a driving direction 105 on a road 140. Thevehicle 100 may comprise a means for transportation in broad sense such as e.g. a truck, acar, a motorcycle, a trailer, a bus, a bike, or other similar manned or unmanned means of COHVGYGHCG.

The vehicle 100 may be driver controlled or driverless (i.e. autonomously controlled) in dif-ferent embodiments. However, for enhanced clarity, the vehicle 100 is subsequently de-scribed as having a driver.

The vehicle 100 comprises a first sensor 110 of a first type and a second sensor 120 of asecond type, for detecting objects in front of the vehicle 100, such as e.g. another vehicle130.

By using detection signals from the sensors 110, 120 of the other vehicle 130, various phys-ical parameters of the other vehicle 130 may be determined, such as e.g. height of the vehicle130, width of the vehicle 130, nature of the vehicle tail, etc. Also for example vehicle speedand/ or vehicle acceleration of the other vehicle 130 may be estimated. Based on the meas-ured information of the sensors 110, 120, it may be determined if the vehicle 130 in front issuitable for platooning, for the own vehicle 100; i.e. for forming an ad hoc platoon comprisingthe vehicle 100 and the other vehicle 130 (and possibly other vehicles in front of the othervehicle 130, and/ or behind the own vehicle 100).

Such platoon, or coordinated group of vehicles may be described as a chain of coordinated,vehicles travelling in the same direction 105 at given inter-vehicular distances and velocity.

The inter-vehicular distances may be fixed or variable in different embodiments. Thus thedistances may be e.g. some centimetres, some decimetres, some meters or some tenths ofmeters in different embodiments. Alternatively, each vehicle in the platoon may have a dif-ferent distance to the vehicle following, or leading, vehicle, than other vehicles in the coordi-nated group.

The preceding vehicle 130 may be considered suitable for platooning when the precedingvehicle 130 has about the same height and width as the own vehicle 100, or being higherand/ or wider. Other criteria may be applied, such as the type of vehicles may be consideredto be similar, estimated weight/ acceleration capacity of the vehicles, etc. lt may be noted that sometimes the preceding vehicle 130 may be suitable for platooningunder some circumstances, for example a timber vehicle being loaded, while inappropriatefor platooning when not loaded. However, this is solved according to the disclosed solutionby analysing the tail of the preceding vehicle 130. The herein discussed measurementsmade of the preceding vehicle 130 (height, width) concerns the tail of the preceding vehicle130.

The first sensor 110, of a first type may be based on emission of electromagnetic radiationand detection of reflections of the emitted electromagnetic radiation from the tail of the pre-ceding vehicle 130, and may comprise e.g. a radar, a lidar, an ultrasound device or similardevice, in different embodiments.

The second sensor 120, of the second type is based on capturing of an image of the tail ofthe preceding vehicle 130 may comprise a camera, a stereo camera, an infrared camera, avideo camera, a time-of-flight camera, or a similar device, in different embodiments.

According to some embodiments, firstly, a detection and estimation of the tail of the preced-ing vehicle 130 is conducted. There are different vehicle types or tails on the road 140 thatare to be separated and identified in order to determine if the preceding vehicle 130 is suit-able for forming a platoon with the own vehicle 100.

While the first sensor 110, e.g. a radar, may provide information regarding the precedingvehicle dynamics. The second sensor 120, e.g. a camera, can provide additional informationof the preceding vehicle 130, such as vehicle width, height, and other vehicle tail character-istics, i.e. such as if it is open or closed.

The information may then be fused and a probability check may be made on the reliability ofthe information provided to the vehicle type classification method. Furthermore, environmentinformation such as e.g. the light conditions (day, dusk, night, fog, rain, snow, etc.) may beused to estimate the confidence of the identification process, e.g. by assuming differentstandard deviations for properties measured by the second sensor 120, such as the camera.Also, the detection range may be used to estimate the standard deviation, in some embodi- mentS.

The vehicle type identification method may be illuminated in more detail by the following example: Measurable properties such as width, height, vehicle acceleration, etc., of the preceding ve-hicle 130 may be determined and used to calculate an instantaneous probability of determin-ing the type of the preceding vehicle 130. Several instantaneous probabilities can then beweighed together with different weights in some embodiments.

For example, heavy vehicles may be assumed to be more than ~2m wide while passengercars are assumed to be between 1.5 and 2.1 m wide. lt may also be determined, based on signals of the first sensor 110 and the second sensor120, that the tail of the in-front vehicle 130 is homogeneous/ solid, or if it comprises holes/openings, such as on e.g. an empty timber vehicle.

The instantaneous probabilities for several classification types may then be low-pass filteredand when the filtered probability exceeds a threshold value, the type with the highest proba-bility may be locked in some embodiments.

Further, as soon as a suitable tail end of the preceding vehicle 130 has been detected forfuel efficient platooning, the information may be sent, possibly together with a GPS-tag, to aback-end office over a suitable wireless medium such as WiFi, Bluetooth, the mobile phonenetwork, etc., in different embodiments. Thereby, the back-end office can monitor the ratiofor which platooning has been conducted over the whole transport segment. Naturally, theengine torque and instantaneous fuel consumption can also be determined and sent to theback-end office to monitor how much energy or fuel reduction that occurs when the vehicle100 is travelling in a platoon under favourable conditions. ln some embodiments, the involved vehicles 100, 130 may be configured for wireless inter-communication between each other, e.g. via Vehicle-to-Vehicle (V2V) communication, e.g.based on Dedicated Short-Range Communications (DSRC) devices. DSRC works in 5.9GHz band with bandwidth of 75 MHz and approximate range of 1000 m in some embodi-ments. By such wireless communication, the vehicles 100, 130 may coordinate their move-ments, which will enable a more informed and advanced control that in turn will facilitate asmaller inter-vehicle spacing with maintained safety. Thereby the fuel gain will be increasedas the air resistance will be further reduced.

However, when a suitable preceding vehicle 130 is discovered according to the disclosedmethod, it is desired to form a platoon with that vehicle 130, also when any or both of theinvolved vehicles 100, 130 lack ability of wireless communication with each other.

The disclosed method enables the possibility of creating a service for monitoring how mucheach vehicle in a vehicle fleet is actually platooning under favourable conditions. Therebythe vehicle owner may detect vehicle drivers who are unwilling to drive in platoons; vehicledrivers who select inappropriate other vehicles to form platoons with, etc. Further, statisticsmay be established based on the obtained information concerning percentage of driving in/out of platoons; how much fuel that is saved, etc. Thus, the disclosed method is essential forhelping the fleet owners to monitor how the vehicles are being operated in traffic and whetherplatooning is conducted under favourable conditions. Thereby fuel is saved.

Figure 1B illustrates the vehicle 100, driving in the driving direction 105, following a preced-ing vehicle 130 on a road 140, e.g. the scenario in Figure 1A as seen from above.

The vehicle 100 has a first sensor 110, of a first type such as a laser, for measuring at leastone parameter of a tail of the preceding vehicle 130, such as height of the preceding vehicle130 and/ or width of the preceding vehicle 130. The vehicle 100 may also have a set ofsensors 110 of the first type, such as one instance of the first sensor 110 on the left side ofthe vehicle 100 and a second instance of the first sensor 110 on the right side of the vehicle100.

The vehicle 100 also has a second sensor 120, of a second type such as a camera, formeasuring at least one parameter of the tail of the preceding vehicle 130.

The second sensor 120 is forwardly directed in the driving direction 105 and may be situatede.g. at the front of the vehicle 100, behind the windscreen of the vehicle 100.

Mounting the fon/vardly directed second sensor 120 behind the windshield have some ad-vantages compared to externally mounted camera systems. These advantages include thepossibility to use windshield wipers for cleaning and using the light from headlights to illumi-nate objects in the camera's field of view. lt is also protected from dirt, snow, rain and tosome extent also from damage, vandalism and/ or theft. Such sensor 120 may also be usedfor a variety of other tasks.

The second sensor 120 comprises, or may be connected to a control unit configured to imagerecognition/ computer vision and object recognition.

Computer vision is a technical field comprising methods for acquiring, processing, analysing,and understanding images and, in general, high-dimensional data from the real world in orderto produce numerical or symbolic information. A theme in the development of this field has been to duplicate the abilities of human vision by electronically perceiving and understandingan image. Understanding in this context means the transformation of visual images (the inputof retina) into descriptions of world that can interface with other thought processes and elicitappropriate action. This image understanding can be seen as the disentangling of symbolicinformation from image data using models constructed with the aid of geometry, physics,statistics, and learning theory. Computer vision may also be described as the enterprise ofautomating and integrating a wide range of processes and representations for vision percep- tion.

The image data of the second sensor 120 may take many forms, such as e.g. images, video sequences, views from multiple cameras, or multi-dimensional data from a scanner.

Computer vision may comprise e.g. scene reconstruction, event detection, video tracking,object recognition, object pose estimation, learning, indexing, motion estimation, and image restoration, just to mention some examples. ln some embodiments, the image recognition of images captured by the second sensor 120may be used for detecting size and/ or category of the preceding vehicle 130, e.g. for con-firming the data captured by the first sensor 110 in some embodiments. Further, imagerecognition may be used for detecting whether the preceding vehicle 130 is inappropriate forforming a platoon, even if the height and/ or width of the preceding vehicle 130 appears tobe appropriate.

Some examples of such vehicles may be emergency vehicles (which may have to exceedtraffic regulations in an emergency situation); vehicles with dangerous goods/ hazardousmaterials such as corrosive, oxidising, flammable, explosive, radioactive, asphyxiating, bio-hazardous, toxic, pathogenic, and/ or allergenic materials (as an incident may have devas-tating consequences); city busses (firstly because it may be unpleasant for the passengersof the bus, secondly because a city bus typically stops regularly at bus stops); vehicles be-longing to a driving school for practising driving (may put unnecessary additional stress onthe driving school trainee); military vehicles (which may contain explosives or even nuclearweapons without any particular markings); a platform truck with insufficiently covered or se-cured, etc.

Emergency vehicles may be detected by comparing a tail image with a reference tail imagein some embodiments. Vehicles with dangerous goods may be detected by detecting a signin the tail of such vehicle, informing about the dangerous content. Busses may be detectedby discovering a glass window at the tail of the preceding vehicle 130. Vehicles belonging to 11 vehicle schools may be detected by detecting a sign at the tail of such vehicle. Military vehi-cles may be detected by the camouflage colour scheme, etc.

Figure 2A illustrates the scenario in Figure 1A and/ or Figure 1B, as it may be perceivedfrom the driver of the vehicle 100 (if any), driving behind the preceding vehicle 130 whiledriving in the driving direction 105.

The vehicle 100 comprises a sensor 305 configured to detect environmental conditions in-fluencing sensor detections of the first type of sensor 110 and/ or the second type of sensor120 at the vehicle 100. The sensor 305 may detect e.g. light conditions (by a light sensor),snow/ rain detection (by a rain sensor), fog detection (by a fog sensor) etc. The sensor 305 may comprise any, some or all of these enumerated sensors in different embodiments.

The vehicle 100 comprises a control unit 310. The control unit 310 is arranged in the vehicle100 for determining if a preceding vehicle 130 is suitable for platooning, and performing var-ious calculations, computations and control tasks associated therewith. Thus the control unit310 is configured to communicate via a wired or wireless communication interface with thefirst sensor 110 and the second sensor 120. Thereby parameters of a tail of the precedingvehicle 130 as measured by the sensors 110, 120 may be obtained. Based upon the obtainedparameters, a probability value of the preceding vehicle 130 being suitable for platooningwith the vehicle 100, is estimated and in case the estimated probability value exceeds athreshold value, it is determined that the preceding vehicle 130 is suitable for platooning withthe vehicle 100.

The vehicle 100 also comprises a communication device 320, for wireless communicationwith a vehicle external entity 350, such as e.g. a back-end office, a fleet management portal,a vehicle service planning tool, or similar entity which may be accessible for the vehicleowner. The vehicle external entity 350 may comprise a transceiver 360 for receiving/ com-municating with the communication device 320 in the vehicle 100. The vehicle external entity350 may also comprise a computational unit 370 and a database 380. Information concern-ing detected other vehicles 130 suitable for platooning may be stored in the database 380,e.g. together with information concerning geographical position of the vehicle 100.

The geographical position of the vehicle 100 may be determined by a positioning device 330,or navigator, in the vehicle 100, which may be based on a satellite navigation system suchas the Navigation Signal Timing and Ranging (Navstar) Global Positioning System (GPS),Differential GPS (DGPS), Galileo, GLONASS, or the like. 12 The positioning device 330 may be connected to a database comprising map data. Suchdatabase may be situated in the vehicle 100, or possibly external to the vehicle 100 in someembodiments.

The geographical position of the positioning device 330, (and thereby also of the vehicle 100)may be made continuously with a certain predetermined, or configurable time intervals ac- cording to various embodiments.

Positioning by satellite navigation is based on distance measurement using triangulationfrom a number of satellites 340-1, 340-2, 340-3, 340-4. ln this example, four satellites 340-1, 340-2, 340-3, 340-4 are depicted, but this is merely an example. l\/|ore than four satellites340-1, 340-2, 340-3, 340-4 may be used for enhancing the precision, or for creating redun-dancy. The satellites 340-1, 340-2, 340-3, 340-4 continuously transmit information about timeand date (for example, in coded form), identity (which satellite 340-1, 340-2, 340-3, 340-4that broadcasts), status, and where the satellite 340-1, 340-2, 340-3, 340-4 are situated atany given time. The GPS satellites 340-1, 340-2, 340-3, 340-4 sends information encodedwith different codes, for example, but not necessarily based on Code Division Multiple Ac-cess (CDMA). This allows information from an individual satellite 340-1, 340-2, 340-3, 340-4 distinguished from the others' information, based on a unique code for each respectivesatellite 340-1, 340-2, 340-3, 340-4. This information can then be transmitted to be receivedby the appropriately adapted positioning device comprised in the vehicle 100.

Distance measurement can according to some embodiments comprise measuring the differ-ence in the time it takes for each respective satellite signal transmitted by the respectivesatellites 340-1, 340-2, 340-3, 340-4 to reach the positioning device 330. As the radio signalstravel at the speed of light, the distance to the respective satellite 340-1, 340-2, 340-3, 340-4 may be computed by measuring the signal propagation time.

The positions of the satellites 340-1, 340-2, 340-3, 340-4 are known, as they continuouslyare monitored by approximately 15-30 ground stations located mainly along and near theearth's equator. Thereby the geographical position, i.e. latitude and longitude, of the vehicle100 may be calculated by determining the distance to at least three satellites 340-1, 340-2,340-3, 340-4 through triangulation. For determination of altitude, signals from four satellites340-1, 340-2, 340-3, 340-4 may be used according to some embodiments.

The geographical position of the positioning device 330, (and thereby also of the vehicle100), as well as time, vehicle speed, heading, etc., may be determined continuously, or at a certain predetermined or configurable time interval according to various embodiments. 13 The geographical position of the vehicle 100 may alternatively be determined, e.g. by havingtransponders positioned at known positions around the route and a dedicated sensor in thevehicle 100, for recognising the transponders and thereby determining the position; by de-tecting and recognising WiFi networks (WiFi networks along the route may be mapped withcertain respective geographical positions in a database); by receiving a Bluetooth beaconingsignal, associated with a geographical position, or other signal signatures of wireless signalssuch as e.g. by triangulation of signals emitted by a plurality of fixed base stations with knowngeographical positions. The position may alternatively be entered by the driver of the vehicle100, if any.

Communication may be made over a wireless communication interface, such as e.g. Vehicle-to-Vehicle (V2V) communication, or Vehicle-to-Structure (V2X) communication in some em-bodiments. ln some embodiments, the communication between the vehicle 100 and the vehicle externalstructure 350 may be performed via V2X communication, e.g. based on Dedicated Short-Range Communications (DSRC) devices. DSRC works in 5.9 GHz band with bandwidth of75 l\/lHz and approximate range of 1000 m in some embodiments.

The wireless communication may be made according to any IEEE standard for wireless ve-hicular communication like e.g. a special mode of operation of IEEE 802.11 for vehicularnetworks called Wireless Access in Vehicular Environments (WAVE). IEEE 802.11p is anextension to 802.11 Wireless LAN medium access layer (MAC) and physical layer (PHY)specification.

Such wireless communication interface may comprise, or at least be inspired by wirelesscommunication technology such as Wi-Fi, Wireless Local Area Network (WLAN), Ultra Mo-bile Broadband (Ul\/IB), Bluetooth (BT), Near Field Communication (NFC), Radio-FrequencyIdentification (RFID), Z-wave, ZigBee, lPv6 over Low power Wireless Personal Area Net-works (6LoWPAN), Wireless Highway Addressable Remote Transducer (HART) Protocol,Wireless Universal Serial Bus (USB), optical communication such as Infrared Data Associa-tion (IrDA) or infrared transmission to name but a few possible examples of wireless com- munications in some embodiments.

The communication may alternatively be made over a wireless interface comprising, or atleast being inspired by radio access technologies such as e.g. SGPP LTE, LTE-Advanced, 14 E-UTRAN, UMTS, GSM, GSM/ EDGE, WCDMA, Time Division Multiple Access (TDMA) net-works, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA)networks, Single-Carrier FDMA (SC-FDMA) networks, Worldwide lnteroperability for Micro-wave Access (WiMax), or Ultra Mobile Broadband (UMB), High Speed Packet Access(HSPA) Evolved Universal Terrestrial Radio Access (E-UTRA), Universal Terrestrial RadioAccess (UTRA), GSM EDGE Radio Access Network (GERAN), 3GPP2 CDMA technologies,e.g., CDMA2000 1x RTT and High Rate Packet Data (HRPD), or similar, just to mention some few options, via a wireless communication network.

Communication between the various units 110, 120, 305, 310, 320, 330 in the vehicle 100may interactively communicate between themselves via e.g. a wired or wireless communi-cation bus. The communication bus may comprise e.g. a Controller Area Network (CAN)bus, a Media Oriented Systems Transport (MOST) bus, or similar. However, the communi-cation may alternatively be made over a wireless connection comprising, or at least be in- spired by any of the previously discussed wireless communication technologies.

Figure 2B illustrates the scenario in Figure 1A and/ or Figure 1B, as it may be perceivedfrom the driver of the vehicle 100 (if any), driving behind the preceding vehicle 130 whiledriving in the driving direction 105; which is alternative to the embodiment illustrated in Figure2A.

All entities and units discussed in Figure 2A are the same, similar or corresponding in theembodiment illustrated in Figure 2B, except for that there is no communication device 320and no wireless communication with the vehicle external entity 350. lnstead, the informationconcerning detection and determination of the preceding vehicle 130 as suitable for platoonformation together with the vehicle 100, possibly together with a representation of the geo-graphical position of the vehicle 100, may be stored in a database 380 situated in the vehicle100. When the vehicle reaches e.g. a garage of the vehicle owner, or other vehicle externalentity, the information stored in the database 380 may be transferred to a database of thevehicle owner via a wired or wireless communication interface, such as e.g. a Universal Se- rial Bus (USB) connection; or similar solution.

Figure 3 illustrates an example of how a detected vehicle width of the preceding vehicle 130may be used in a truth function, for estimating whether the preceding vehicle 130 is a HeavyDuty Vehicle (HDV). ln a non-limiting example, measurement data obtained from the first sensor 110 and/ or thesecond sensor 120 may be used for determining the vehicle width, like e.g., 2. 1 metres. By using the truth function, a likelihood, or probability value, corresponding to the determinedvehicle width may be extracted from the truth function, such as e.g., 0.75. Then, by compar-ing the obtained likelihood 0.75 with a threshold value, such as e.g., 0.5, it may be deter-mined that the preceding vehicle 130 is suitable for platooning when the determined proba-bility value exceeds the threshold value.

The threshold value may be predetermined or configurable in different embodiments, andmay be set to e.g. any arbitrary value exceeding zero but smaller than or equal to one indifferent embodiments, depending on the level of reliability that is desired. The higher thethreshold value is set, the more reliable is the conclusion that the preceding vehicle 130 is aheavy vehicle suitable for platooning. lt may thereby be avoided that a platoon is formed with an inappropriate preceding vehicle130, e.g. a vehicle 130 having a tail being smaller than the front of the own vehicle 100,which would not be optimal from a fuel saving perspective. This may present a problemperhaps in particular for autonomous vehicles 100, which may decide to form a platoon in-dependently in some embodiments.

The illustrated example in Figure 3 only relates to vehicle width; however, other similar truthfunctions may be established and utilised for vehicle tail height; and/ or a combination of tailheight and tail width, etc.

Further, different truth functions may be utilised, depending on environmental conditions. Forexample, heavy snow/ rain may disturb radar signals, which thus may be less reliable whilee.g. darkness may influence the reliability of camera images, etc. lt may thus be appropriatein some embodiments to apply a larger safety margin for the detected parameter values in rough environmental conditions.

Furthermore, obviously, the utilised truth function is dependent on the dimensions of the ownvehicle 100. For achieving satisfying fuel savings, it is desired to form a platoon with a pre-ceding vehicle 130 having the same or higher height, and/ or the same or broader width.

Thus a motorcycle may form a platoon when driving behind a truck, and save a satisfyingamount of fuel, but not the opposite.

Figure 4 illustrates an example of a method 400 according to an embodiment. The flow chartin Figure 4 shows the method 400 in a vehicle 100. The method 400 aims at determining ifa preceding vehicle 130, driving in front of the vehicle 100 on a road 140 is suitable for 16 platooning, i.e. creating an ad hoc platoon, together with the vehicle 100.

The suitability of the preceding vehicle 130 to form a platoon with the vehicle 100 is depend-ing both of the dimensions (height and width) of the own vehicle 100, which is known, andthe dimensions (height and width) of the preceding vehicle 130. The preceding vehicle 130may be suitable for platooning in case it has at least the same height and width as the vehicle100, in some embodiments.

The road 140, as the concept is utilised herein, may be an asphalt road, a gravel road, apath, a trail, a passage, etc. ln order to be able to determine platoon formation suitability, the method 400 may comprisea number of steps 401-409. However, some of these steps 401-409 may be performed solelyin some alternative embodiments, like e.g. steps 403 and/ or steps 406-409. Further, thedescribed steps 401-409 may be performed in a somewhat different chronological order thanthe numbering suggests. The method 400 may comprise the subsequent steps: Step 401 comprises measuring at least one parameter of a tail of the preceding vehicle 130with a first sensor 110, of a first type.

The first type sensor 110 may be based on emission of electromagnetic radiation and detec-tion of reflections of the emitted electromagnetic radiation from the tail of the preceding ve-hicle 130, in some embodiments, such as e.g. radar, lidar, an ultrasound device or similardevice.

The at least one parameter of the tail of the preceding vehicle 130 may comprise height ofthe tail, width of the tail, open/ closed tail or similar parameter.

Step 402 comprises measuring at least one parameter of the tail of the preceding vehicle130 with a second sensor 120, of a second type.

The second sensor, of the second type may be based on capturing of an image of the tail ofthe preceding vehicle 130.

Step 403, which only may be performed in some embodiments, comprises detecting envi-ronmental conditions influencing sensor detections of the first type of sensor 110 and/ or thesecond type of sensor 120 at the vehicle 100. 17 Such environmental conditions may comprise darkness, fog, snow, rain, smoke, etc. Theenvironmental conditions may be made with a sensor 305 of the vehicle 100.

When parameters are measured with the first type sensor 110 and/ or the second type sen-sor 120, perhaps in particular the second type sensor 120, in rough environmental conditionssuch as darkness, fog, snow, rain, smoke, etc., they may be given less credibility. ln someembodiments, different truth functions may be used, based on the environmental conditions.

Thereby, by combining measurements made by at least two different types of sensors 110,120 the risk of making erroneous decisions due to incorrectly measured parameter values iseliminated, or at least reduced, leading to a more reliable functionality.

Step 404 comprises estimating a probability value of the preceding vehicle 130 being suita-ble for platooning, based on the measured 401, 402 at least one parameter.

The probability value of the preceding vehicle 130 may be estimated 404, further based onthe detected 403 environmental conditions, in some embodiments wherein step 403 hasbeen performed. ln some embodiments, wherein both the vehicle 100 and the preceding vehicle 130 are con-figured for wireless communication exchange, the estimation of the probability value of thepreceding vehicle 130 being suitable for platooning with the vehicle 100 may be further basedon information received from the preceding vehicle 130 via the wireless communication ex-change, concerning the size of the tail of the preceding vehicle 130, such as height of the tailand/ or width of the tail.

Step 405 comprises determining that the preceding vehicle 130 is suitable for platooningwhen the determined 404 probability value exceeds a threshold value.

The threshold value may be e.g. 0.5, 0.6, 0.7, 0.8, 0.9, etc., or there about, in different em-bodiments. ln some embodiments, the preceding vehicle 130 is not determined 405 to be suitable forplatooning when the preceding vehicle 130 is recognised as any of: an emergency vehicle,a vehicle comprising dangerous goods/ hazardous materials, a vehicle belonging to a drivingschool, a city bus. Such recognition may be made via image recognition. lt is thereby possible to avoid forming a platoon with a vehicle 130, which if only size would 18 be regarded, may be considered suitable. Thereby inappropriate vehicle behaviour and/ oraccidents may be avoided. ln some embodiments, a recommendation to the driver to form a platoon with the precedingvehicle 130 may be outputted, e.g. on a display in the cab, by a loudspeaker, by a tactical device or a combination thereof.

Step 406, which only may be performed in some embodiments, comprises determining ge-ographical position of the vehicle 100 when the preceding vehicle 130 is determined 405suitable for platooning.

The geographical position of the vehicle 100 may be determined by a positioning device 330 in some embodiments.

Such estimation of geographical position may be made continuously or at some configurableor predetermined time interval of any arbitrary length, from e.g. some seconds, to several hours or even days, in some embodiments.

The determined geographical position may be stored in the database 380 in some embodi- mentS.

Step 407, which only may be performed in some embodiments, comprises obtaining infor-mation concerning whether the vehicle 100 is driving in a platoon formation behind the pre-ceding vehicle 130, or not.

This may be determined by measuring the inter-vehicular distance between the vehicle 100and the preceding vehicle 130 in some embodiments, e.g. via the first sensor 110. ln casethe determined distance is smaller than a threshold distance (which may be velocity depend-ent), such as e.g. five meters when driving in 80 km/ h (merely an illustrating, non-limitingexample), it may be determined that the vehicles 100, 130 are driving in a common platoon. ln case both the vehicle 100 and the preceding vehicle 130 are configured to communicatewirelessly, it may be determined based on analyse of the wireless communication that thevehicles 100, 130 has formed a platoon in some embodiments.

Step 408, which only may be performed in some embodiments, comprises storing the deter-mined 406 position of the vehicle 100 and the obtained 407 information in a database 380. 19 The database 380 may be situated in a vehicle external entity 350 in some embodiments, orin the vehicle 100 in different embodiments. ln some embodiments also information concerning geographical position of the vehicle 100when a suitable preceding vehicle 130 has been detected may be stored in the database380.

Step 409, which only may be performed in some embodiments, comprises determining seg-ments of the vehicle route where it has been determined 405 that the preceding vehicle 130is suitable for platooning, but the vehicle 100 has not been driving in platooning mode, in some embodiments.

This information may also be stored in the database 380 in some embodiments.

Figure 5 presents a system 500. The system 500 aims at determining if a preceding vehicle 130 is suitable for platooning with a vehicle 100, driving behind that vehicle 100.

The system 500 comprises a first sensor 110 of a first type such as e.g. radar, lidar or similar,for measuring at least one parameter of a tail of the preceding vehicle 130.

Thus the first sensor 110, of a first type may be based on emission of electromagnetic radi-ation and detection of reflections of the emitted electromagnetic radiation from the tail of thepreceding vehicle 130.

The system 500 also comprises a second sensor 120 of a second type, configured for cap-turing an image such as e.g. a camera, a video camera etc., for measuring at least one parameter of the tail of the preceding vehicle 130.

The second sensor 120, of the second type may be based on capturing of an image of thetail of the preceding vehicle 130.

The system 500 furthermore comprises a control unit 310 in the vehicle 100, for determiningif a preceding vehicle 130 is suitable for platooning. The control unit 310 may perform themethod 400 according to any, some or all of the previously described steps 401-409 as de-scribed above and illustrated in Figure 4. The control unit 310 is configured to send a firstcontrol signal to a first sensor 110, of a first type, for measuring at least one parameter of atail of the preceding vehicle 130. Further the control unit 310 is configured to send a secondcontrol signal to a second sensor 120, of a second type, for measuring at least one parameter of the tail of the preceding vehicle 130. ln addition, the control unit 310 is configured to esti-mate a probability value of the preceding vehicle 130 being suitable for platooning, based onthe measured at least one parameter. Also, furthermore, the control unit 310 is configured todetermine that the preceding vehicle 130 is suitable for platooning when the determinedprobability value exceeds a threshold value. ln some embodiments, the control unit 310 may be configured to determine geographicalposition of the vehicle 100 when the preceding vehicle 130 is determined suitable for pla-tooning, e.g. via a positioning unit 330.

Further the control unit 310 may also be configured to obtain information concerning whetherthe vehicle 100 is driving in a platoon formation behind the preceding vehicle 130 or not.

This may be made e.g. by measuring the distance between the vehicles 100, 130 e.g. viathe first sensor 110. Also, alternatively, it may be determined based on wireless signallingexchanged between the vehicles 100, 130, in case both vehicles 100, 130 are configured for wireless communication. ln further addition the control unit 310 may also be configured to store the determined posi-tion of the vehicle 100 and the obtained information in a database 380. The database 380may be comprised in the vehicle 100 in some embodiments, or in a vehicle external entity360 in some embodiments.

Additionally, the control unit 310 may also be configured to detect, via a sensor 305, envi-ronmental conditions influencing sensor detections of the first type of sensor 110 and/ or thesecond type of sensor 120 at the vehicle 100, such as light, darkness, snow, rain, fog, etc.

Further the control unit 310 may adjust the estimated probability value of the preceding ve-hicle 130, further based on the detected environmental conditions. ln some embodiments wherein both the vehicle 100 and the preceding vehicle 130 are con-figured for wireless communication exchange, the control unit 310 may be configured to es-timate the probability value of the preceding vehicle 130 being suitable for platooning, furtherbased on information received from the preceding vehicle 130 via the wireless communica-tion exchange, concerning the size of the tail of the preceding vehicle 130, i.e. height and/or width of the vehicle tail. 21 Further the control unit 310 may be configured to determine segments of the vehicle routewhere it has been determined that the preceding vehicle 130 is suitable for platooning, butthe vehicle 100 has not been driving in platooning mode. This information may be stored inthe database 380 in some embodiments.

The control unit 310 may comprise a receiving unit 510 configured for receiving informationfrom the environmental sensor 305, the first sensor 110, the second sensor 120 and/ or thepositioning unit 330.

The control unit 310 may further comprise a processor 520 configured for performing variouscalculations for conducting the method 400 according to at least some of the previously de-scribed method steps 401-409 for determining if a preceding vehicle 130 of the vehicle 100is suitable for platooning.

Such processor 520 may comprise one or more instances of a processing circuit, i.e. a Cen-tral Processing Unit (CPU), a processing unit, an Application Specific Integrated Circuit(ASIC), a microprocessor, or other processing logic that may interpret and execute instruc-tions. The herein utilised expression “processor” may thus represent a processing circuitrycomprising a plurality of processing circuits, such as, e.g., any, some or all of the ones enu-merated above.

Furthermore, the control unit 310 may comprise a memory 525 in some embodiments. Theoptional memory 525 may comprise a physical device utilised to store data or programs, i.e.,sequences of instructions, on a temporary or permanent basis. According to some embodi-ments, the memory 525 may comprise integrated circuits comprising silicon-based transis-tors. The memory 525 may comprise e.g. a memory card, a flash memory, a USB memory,a hard disc, or another similar volatile or non-volatile storage unit for storing data such ase.g. ROIVI (Read-Only Memory), PROIVI (Programmable Read-Only Memory), EPROIVI(Erasable PROIVI), EEPROIVI (Electrically Erasable PROIVI), etc. in different embodiments.

Further, the control unit 310 may comprise a signal transmitting unit 530. The signal trans-mitting unit 530 may be configured for transmitting control signals for controlling the sensors305, 110, 120 and the positioning device 330; for wireless communication with the vehicleexternal entity 360 via the communication device 350 for wireless communication; and/ or for storing data in the database 380 in some embodiments.

The previously described method steps 401-409 to be performed in the control unit 310 maybe implemented through the one or more processors 520 within the control unit 310, together 22 with computer program product for performing at least some of the functions of the steps401 -409. Thus a computer program product, comprising instructions for performing the steps401-409 in the control unit 310 may perform the method 400 comprising at least some of thesteps 401-409 for determining if a preceding vehicle (130) of a vehicle (100) is suitable forplatooning, when the computer program is loaded into the one or more processors 520 ofthe control unit 310.

The described steps 401-409 thus may be performed by a computer algorithm, a machineexecutable code, a non-transitory computer-readable medium, or a software instructions pro-grammed into a suitable programmable logic such as the one or more processors 520 in the control unit 310 in various embodiments.

The computer program product mentioned above may be provided for instance in the formof a data carrier carrying computer program code for performing at least some of the step401-409 according to some embodiments when being loaded into the one or more proces-sors 520 of the control unit 310. The data carrier may be, e.g., a hard disk, a CD ROIVI disc,a memory stick, an optical storage device, a magnetic storage device or any other appropri-ate medium such as a disk or tape that may hold machine readable data in a non-transitorymanner. The computer program product may furthermore be provided as computer programcode on a server and downloaded to the control unit 310 remotely, e.g., over an Internet or an intranet connection.

Further, some embodiments may comprise a vehicle 100, comprising the control unit 310,as described above, for performing the method according to at least some of the describedmethod steps 401-409.

The terminology used in the description of the embodiments as illustrated in the accompa-nying drawings is not intended to be limiting of the described method 400, control unit 310;computer program, and/ or system 500. Various changes, substitutions and/ or alterationsmay be made, without departing from invention embodiments as defined by the appended claims.

As used herein, the term "and/ or" comprises any and all combinations of one or more of theassociated listed items. The term “or” as used herein, is to be interpreted as a mathematicalOR, i.e., as an inclusive disjunction; not as a mathematical exclusive OR (XOR), unless ex-pressly stated otherwise. ln addition, the singular forms "a", "an" and "the" are to be inter-preted as “at least one", thus also possibly comprising a plurality of entities of the same kind,unless expressly stated othen/vise. lt will be further understood that the terms "includes", 23 "comprises", "including" and/ or "comprising", specifies the presence of stated features, ac-tions, integers, steps, operations, elements, and/ or components, but do not preclude thepresence or addition of one or more other features, actions, integers, steps, operations, ele-ments, components, and/ or groups thereof. A single unit such as e.g. a processor may fulfil5 the functions of several items recited in the claims. The mere fact that certain measures arerecited in mutually different dependent claims does not indicate that a combination of thesemeasures cannot be used to advantage. A computer program may be stored/ distributed ona suitable medium, such as an optical storage medium or a solid-state medium suppliedtogether with or as part of other hardware, but may also be distributed in other forms such 10 as via Internet or other wired or wireless communication system.

Claims (15)

1. A method (400) in a vehicle (100), for determining if a preceding vehicle (130) issuitable for platooning, which method (400) comprises: measuring (401) at least one parameter of a tail of the preceding vehicle (130) witha first sensor (1 10), of a first type; measuring (402) at least one parameter of the tail of the preceding vehicle (130)with a second sensor (120), of a second type; estimating (404) a probability value of the preceding vehicle (130) being suitable forplatooning, based on the measured (401, 402) at least one parameter; and determining (405) that the preceding vehicle (130) is suitable for platooning whenthe determined (404) probability value exceeds a threshold value.

2. The method (400) according to claim 1, further comprising: determining (406) geographical position of the vehicle (100) when the precedingvehicle (130) is determined (405) suitable for platooning; obtaining (407) information concerning whether the vehicle (100) is driving in a pla-toon formation behind the preceding vehicle (130) or not; and storing (408) the determined (406) position of the vehicle (100) and the obtained(407) information in a database (380).

3. The method (400) according to any of claim 1 or claim 2 further comprising: detecting (403) environmental conditions influencing sensor detections of the firsttype of sensor (1 10) and/ or the second type of sensor (120) atthe vehicle (100); and whereinthe probability value of the preceding vehicle (130) is estimated (404), further based on thedetected (403) environmental conditions.

4. The method (400) according to any of claims 1-3, wherein both the vehicle (100)and the preceding vehicle (130) are configured for wireless communication exchange, andwherein the estimation (404) of the probability value of the preceding vehicle (130) beingsuitable for platooning is further based on information received from the preceding vehicle(130) via the wireless communication exchange, concerning the size of the tail of the pre-ceding vehicle (130).

5. The method (400) according to any of claims 1-4, wherein the first sensor (110), ofa first type is based on emission of electromagnetic radiation and detection of reflections ofthe emitted electromagnetic radiation from the tail of the preceding vehicle (130), while thesecond sensor (120), of the second type is based on capturing of an image of the tail of thepreceding vehicle (130).

6. The method (400) according to any of claims 2-5, further comprising:determining (409) segments of the vehicle route where it has been determined (405)that the preceding vehicle (130) is suitable for platooning, but the vehicle (100) has not been driving in platooning mode.

7. The method (400) according to any of claims 1-6, wherein the preceding vehicle(130) is not determined (405) to be suitable for platooning when the preceding vehicle (130)is recognised as any of: an emergency vehicle, a vehicle comprising dangerous goods/ haz-ardous materials, a vehicle belonging to a driving school, a city bus.

8. A control unit (310) in a vehicle (100), for determining if a preceding vehicle (130) issuitable for platooning, wherein the control unit (310) is configured to: send a first control signal to a first sensor (1 1 0), of a first type, for measuring at leastone parameter of a tail of the preceding vehicle (130); send a second control signal to a second sensor (120), of a second type, for meas-uring at least one parameter of the tail of the preceding vehicle (130); estimate a probability value of the preceding vehicle (130) being suitable for pla-tooning, based on the measured at least one parameter; and determine that the preceding vehicle (130) is suitable for platooning when the de-termined probability value exceeds a threshold value.

9. The control unit (310) according to claim 8, further configured to: determine geographical position of the vehicle (100) when the preceding vehicle(130) is determined suitable for platooning; obtain information concerning whether the vehicle (100) is driving in a platoon for-mation behind the preceding vehicle (130) or not; and store the determined position of the vehicle (100) and the obtained information in adatabase (380).

10. The control unit (310) according to any of claim 8 or claim 9, further configured to:detect, via a sensor (305), environmental conditions influencing sensor detectionsof the first type of sensor (110) and/ or the second type of sensor (120) at the vehicle (100);and wherein the probability value of the preceding vehicle (130) is estimated, further basedon the detected environmental conditions.

11. The control unit (310) according to any of claims 8-10, wherein both the vehicle(100) and the preceding vehicle (130) are configured for wireless communication exchange, 26 and wherein the control unit (310) is configured to estimate the probability value of the pre-ceding vehicle (130) being suitable for platooning, further based on information received fromthe preceding vehicle (130) via the wireless communication exchange, concerning the sizeof the tail of the preceding vehicle (130).

12.of a first type is based on emission of electromagnetic radiation and detection of reflections The control unit (310) according to any of claims 8-1 1 , wherein the first sensor (1 1 0), of the emitted electromagnetic radiation from the tail of the preceding vehicle (130), while thesecond sensor (120), of the second type is based on capturing of an image of the tail of thepreceding vehicle (130).

13. The control unit (310) according to any of claims 8-12, further configured to:determine segments of the vehicle route where it has been determined that the pre-ceding vehicle (130) is suitable for platooning, but the vehicle (100) has not been driving inplatooning mode.

14.cording to any of claims 1-7 when the computer program is executed in a control unit (310), A computer program comprising program code for performing a method (400) ac- according to any of claims 8-13.

15.suitable for platooning, wherein the system (500) comprises: A system (500) for determining if a preceding vehicle (130) of a vehicle (100) is a first sensor (110) of a first type, for measuring at least one parameter of a tail ofthe preceding vehicle (130); a second sensor (120) of a second type, for measuring at least one parameter ofthe tail of the preceding vehicle (130); and a control unit (310), according to any of claims 8-13.