Approaches for determination of vehicle motion

Abstract

An arrangement is disclosed for determining motion of a vehicle in relation to a ground surface. The arrangement comprises a computer system comprising processing circuitry, and one or more radar transceivers mountable on the vehicle. Each radar transceiver is configured to transmit two or more beams directed non-perpendicularly at the ground surface, receive backscatter from the ground surface caused by the two or more beams, and provide backscatter information to the computer system. A first beam of the two or more beams is directed rearwards along a side of the vehicle, and a second beam of the two or more beams is directed laterally across a front of the vehicle. The processing circuitry is configured to determine at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information. Corresponding computer system, vehicle, methods, computer program product, and non-transitory computer-readable storage medium are also disclosed.

Description

APPROACHES FOR DETERMINATION OF VEHICLE MOTIONTECHNICAL FIELD

[0001] The disclosure relates generally to vehicle motion estimation. In particular aspects, the disclosure relates to an arrangement and related approaches for determination of vehicle motion (e.g., in relation to a ground surface supporting the vehicle). The disclosure can be applied to heavy-duty vehicles, such as trucks, buses, and construction equipment, among other vehicle types. Although the disclosure may be described with respect to a particular vehicle, the disclosure is not restricted to any particular vehicle.BACKGROUND

[0002] In relation to vehicle control, it may be beneficial to have an estimation of the current motion of the vehicle (e.g., motion of the vehicle in relation to a ground surface on which the vehicle travels / rests). For example, the vehicle may be controlled based on the motion estimation aiming to achieve a desired motion.

[0003] It is typically desirable to have a motion estimation which is as accurate as possible. Further, it may be desirable to achieve the motion estimation at a relatively low cost (e.g., in terms of one or more of: computational cost, energy consumption, hardware cost, etc.).

[0004] Therefore, there is a need for approaches for vehicle motion estimation.SUMMARY

[0005] According to a first aspect of the disclosure, an arrangement is provided for determining motion of a vehicle in relation to a ground surface. The arrangement comprises a computer system comprising processing circuitry, and one or more radar transceivers mountable on the vehicle. Each radar transceiver is configured to transmit two or more beams directed non-perpendicularly at the ground surface, receive backscatter from the ground surface caused by the two or more beams, and provide backscatter information to the computer system. A first beam of the two or more beams is directed rearwards along a side of the vehicle, and a second beam of the two or more beams is directed laterally across a front ofthe vehicle. The processing circuitry is configured to determine at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information.

[0006] The first aspect of the disclosure may seek to enable provision of motion estimation for a vehicle. A technical benefit may include improved accuracy and / or reduced cost compared to other approaches for vehicle motion estimation.

[0007] Optionally in some examples, including in at least one preferred example, the at least one parameter of the motion of the vehicle in relation to the ground surface may comprise one or more of a lateral speed of the vehicle in relation to the ground surface, a longitudinal speed of the vehicle in relation to the ground surface, and a yaw rate of the vehicle in relation to the ground surface. A technical benefit may include that motion parameters which are suitable for use in vehicle motion management are provided.

[0008] Optionally in some examples, including in at least one preferred example, the processing circuitry may be configured to determine the at least one parameter of the motion of the vehicle in relation to the ground surface by matching the backscatter information to an expected backscatter pattern. The expected backscatter pattern is indicative of a corresponding possible motion of the vehicle in relation to the ground surface. A technical benefit may include that the motion estimation becomes relatively simple.

[0009] Optionally in some examples, including in at least one preferred example, each radar transceiver may be configured to be comprised in a respective side mirror of the vehicle. A technical benefit may include that the radar transceiver is mounted such that it can conveniently provide the two or more beams without obstruction by the vehicle. Alternatively or additionally, a technical benefit may include that no additional protrusions (which may, for example, affect air flow around the vehicle) appear on the exterior of the vehicle due to the mounting of the radar transceiver. Yet alternatively or additionally, a technical benefit may include that the side mirrors may provide the radar transceiver(s) with protection against physical damages.

[0010] Optionally in some examples, including in at least one preferred example, the two or more beams of at least one of the radar transceivers may comprise at least a third beam directed away from the vehicle. A technical benefit may include that the accuracy of the motion estimation may be further increased. Alternatively or additionally, a technical benefit may include that a possibility to detect objects other than ground surface is improved.

[0011] Optionally in some examples, including in at least one preferred example, the processing circuitry may be further configured to detect objects other than ground surface based on the backscatter information. A technical benefit may include that objects (such as other vehicles, pedestrians, animals, infrastructural obstacles, etc.) can be conveniently detected using the same radar transceiver s) as are used for the motion estimation.

[0012] Optionally in some examples, including in at least one preferred example, the processing circuitry may be configured to detect objects other than ground surface by applying a spatial filter to the backscatter information, wherein the spatial filter is configured to separate backscatter of the ground surface from backscatter of objects other than ground surface. A technical benefit may include improved detection accuracy compared to other approaches. Alternatively or additionally, a technical benefit may include that convenient detection is enabled due to the possibility to use a spatial filter which is based on the expected backscatter pattern of the motion estimation.

[0013] According to a second aspect of the disclosure, a computer system is provided for determining motion of a vehicle (in relation to a ground surface. The computer system comprises processing circuitry configured to acquire backscatter information from one or more radar transceivers mountable on the vehicle, and determine at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information. The backscatter information from each radar transceiver is based on backscatter from the ground surface caused by two or more beams transmitted by the radar transceiver and directed non-perpendicularly at the ground surface. A first beam of the two or more beams is directed rearwards along a side of the vehicle, and a second beam of the two or more beams is directed laterally across a front of the vehicle.

[0014] The second aspect of the disclosure may seek to enable provision of motion estimation for a vehicle. A technical benefit may include improved accuracy and / or reduced cost compared to other approaches for vehicle motion estimation.

[0015] According to a third aspect of the disclosure, a vehicle is provided, which comprises the arrangement according to the first aspect and / or the computer system of the second aspect. The third aspect of the disclosure may seek to provide a vehicle with improved motion estimation. A technical benefit may include improved accuracy and / or reduced cost compared to other approaches for vehicle motion estimation.

[0016] According to a fourth aspect of the disclosure, a method is provided for determining motion of a vehicle in relation to a ground surface. The method comprises transmitting (by one or more radar transceivers mounted on the vehicle) two or more beams directed non-perpendicularly at the ground surface. A first beam of the two or more beams is directed rearwards along a side of the vehicle, and a second beam of the two or more beams is directed laterally across a front of the vehicle. The method also comprises receiving (by the one or more radar transceivers) backscatter from the ground surface caused by the two or more beams, providing (by the one or more radar transceivers) backscatter information to a computer system comprising processing circuitry, and determining (by the processing circuitry) at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information. The fourth aspect of the disclosure may seek to enable provision of motion estimation for a vehicle. A technical benefit may include improved accuracy and / or reduced cost compared to other approaches for vehicle motion estimation.

[0017] According to a fifth aspect of the disclosure, a computer-implemented method is provided for determining motion of a vehicle in relation to a ground surface. The method comprises acquiring (by processing circuitry of a computer system) backscatter information from one or more radar transceivers mountable on the vehicle, and determining (by the processing circuitry) at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information. The backscatter information from each radar transceiver is based on backscatter from the ground surface caused by two or more beams transmitted by the radar transceiver and directed non-perpendicularly at the ground surface. A first beam of the two or more beams is directed rearwards along a side of the vehicle, and a second beam of the two or more beams is directed laterally across a front of the vehicle. The fifth aspect of the disclosure may seek to enable provision of motion estimation for a vehicle. A technical benefit may include improved accuracy and / or reduced cost compared to other approaches for vehicle motion estimation.

[0018] According to a sixth aspect of the disclosure, a computer program product is provided comprising program code for performing, when executed by the processing circuitry, the method of any of the fourth and fifth aspects.

[0019] According to a seventh aspect of the disclosure, a non-transitory computer- readable storage medium is provided comprising instructions, which when executed by theprocessing circuitry, cause the processing circuitry to perform the method of any of the fourth and fifth aspects.

[0020] The sixth and / or seventh aspect of the disclosure may seek to convey program code for enabling vehicle motion estimation. A technical benefit may include that new vehicles and / or legacy vehicles comprising one or more suitably mounted radar transceivers may be conveniently configured, by software installation / update, to perform (improved) motion estimation.

[0021] The disclosed aspects, examples (including any preferred examples), and / or accompanying claims may be suitably combined with each other as would be apparent to anyone of ordinary skill in the art. Additional features and advantages are disclosed in the following description, claims, and drawings, and in part will be readily apparent therefrom to those skilled in the art or recognized by practicing the disclosure as described herein.

[0022] There are also disclosed herein computer systems, control units, code modules, computer-implemented methods, computer readable media, and computer program products associated with the above discussed technical benefits.

[0023] In relation to any one or more of the aspects, the at least one parameter of the motion of the vehicle in relation to the ground surface may, for example, be determined based on backscatter information caused by the first beam and backscatter information caused by the second beam.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Examples are described in more detail below with reference to the appended drawings.

[0025] FIG. 1 is a schematic block diagram illustrating an arrangement according to some examples.

[0026] FIG. 2A is a schematic drawing illustrating a side view of a vehicle according to some examples.

[0027] FIG. 2B is a schematic drawing illustrating a top view of a vehicle according to some examples.

[0028] FIG. 3A is a schematic drawing illustrating radar transceiver and vehicle geometry according to some examples.

[0029] FIG. 3B is a schematic drawing illustrating radar transceiver and vehicle geometry according to some examples.

[0030] FIG. 4A is a schematic drawing illustrating backscatter information according to some examples.

[0031] FIG. 4B is a schematic drawing illustrating expected backscatter patterns according to some examples.

[0032] FIG. 5 is a flowchart illustrating a method according to some examples.

[0033] FIG. 6 is a flowchart illustrating a method according to some examples.

[0034] FIG. 7 is a schematic diagram illustrating a computer system for implementing examples disclosed herein according to some examples.

[0035] FIG. 8 is a schematic drawing illustrating a computer program product in the form of a non-transitory computer-readable storage medium according to some examples.

[0036] FIG. 9 is a schematic block diagram of a control unit according to some examples.DETAILED DESCRIPTION

[0037] The detailed description set forth below provides information and examples of the disclosed technology with sufficient detail to enable those skilled in the art to practice the disclosure.

[0038] As already mentioned, it may be beneficial to have an estimation of the current motion of the vehicle (e.g., motion of the vehicle in relation to a ground surface on which the vehicle travels / rests). For example, the vehicle may be controlled based on the motion estimation aiming to achieve a desired motion. In some examples, longitudinal and / or lateral stability control is based on the results of the motion estimation. In some examples, tire wear minimization is based on the results of the motion estimation. In some examples, the results of the motion estimation is used for a lane-keeping assist function. In some examples, the results of the motion estimation - together with wheel speed data - is used for advanced slip control functions (further exemplification may be found in WO 2023 / 169652 Al).

[0039] It is typically desirable that the motion estimation is as accurate as possible, while being provided at a relatively low cost (e.g., in terms computational cost, energy consumption, hardware cost, etc.).

[0040] To this end, the approaches described and exemplified herein aim to provide accurate vehicle motion estimation in a simple manner.

[0041] FIG. 1 schematically illustrates an arrangement 100 for determining motion of a vehicle in relation to a ground surface.

[0042] The arrangement 100 comprises two radar transceivers (RTRX) 130, 140, which are mountable on the vehicle. More generally, an arrangement (such as the arrangement 100) for determining motion of a vehicle in relation to a ground surface may comprise one or more radar transceivers (such as the RTRXs 130, 140) which are mountable on the vehicle.

[0043] The arrangement 100 also comprises a computer system (CS) 110. The computer system 110 comprises processing circuitry (PC) 120. For example, the processing circuitry may be implemented by one or more processor(s). The computer system 110 may be fully or partially comprisable in the vehicle. For example, the computer system 110 may be implemented by a vehicle control unit (VCU) or other suitable hardware.

[0044] Each of the radar transceivers 130, 140 is configured to transmit two or more beams. This may be accomplished in any suitable manner. For example, the radar transceiver may comprise an antenna array and corresponding controlling circuitry to enable the radar transceiver to transmit beams in different directions (either simultaneously or in a time division duplex manner). Alternatively or additionally, the radar transceiver may comprise a plurality of constituent radar transceivers, each configured to transmit a beam in a specific direction.

[0045] Yet alternatively or additionally, the radar transceiver may be configured to transmit using a relatively wide emission pattern (e.g., a relatively broad beam), which leads to illumination of a relatively large section of the ground (and possibly other objects). In this scenario transmission of the relatively wide emission pattern may be seen as implicitly including transmission of the two or more “beams” as described herein. To acquire the backscatter from the ground surface as caused by the two or more “beams”, the radar transceiver may be configured to perform selective angle-of arrival processing to extract the relevant portion(s) of the backscatter as caused by the relatively wide emission pattern.

[0046] When the radar transceivers 130, 140 are appropriately mounted on the vehicle, the two or more beams are directed non-perpendicularly at (towards) the ground surface. For example, each of the two or more beams may be directed at an angle between a vertical extension of the vehicle and a plane which is perpendicular to the vertical extension of thevehicle. Put differently, each of the two or more beams may be directed such that it intersects the ground surface at a non-perpendicular angle.

[0047] The non-perpendicular direction towards the ground surface enable accurate estimation of a motion component of the vehicle (parameter of the motion of the vehicle), wherein a direction of the motion component for velocity may correspond to the projection of the beam direction on the plane which is perpendicular to the vertical extension of the vehicle.

[0048] Furthermore, when the radar transceivers 130, 140 are appropriately mounted on the vehicle, a first beam of the two or more beams is directed rearwards along a side of the vehicle, and a second beam of the two or more beams is directed laterally across a front of the vehicle. For example, the first beam may be directed along (or relatively close to) a longitudinal extension of the vehicle, and the second beam may be directed along (or relatively close to) a lateral extension of the vehicle.

[0049] Covering these different directions enable convenient estimation of a plurality of motion components of the vehicle (e.g., in the plane which is perpendicular to the vertical extension of the vehicle). Typical example motion components which may be beneficial for vehicle control include longitudinal velocity, lateral velocity, and yaw rate.

[0050] Generally, each of the radar transceivers 130, 140 is preferably mounted such that the first and second beams may be transmitted as described above without substantial obstruction by portion(s) of the vehicle. Appropriate mounting of the radar transceivers 130, 140 on the vehicle may, for example, be at front end cab comers of a heavy-duty vehicle, front end comers of a bus, or similar. A particularly suitable mounting of the radar transceivers 130, 140 on the vehicle includes that each of the radar transceivers 130, 140 (or at least one of them) is comprised in (or mounted on) a respective - left / right - side mirror of the vehicle.

[0051] Each of the radar transceivers 130, 140 is also configured to receive backscatter from the ground surface caused by the two or more beams, and provide backscatter information to the computer system 110. Generally, the backscatter received by a radar transceiver is primarily caused by the transmission of that radar transceiver.

[0052] The processing circuitry 120 of the computer system 110 is configured to determine at least one parameter of the motion of the vehicle in relation to the ground surface(e.g., one or more of the motion components mentioned above) based on the acquired backscatter information.

[0053] In some examples, one or more of the radar transceivers 130, 140 (when appropriately mounted on the vehicle) is further configured to transmit a third beam directed away from the vehicle; e.g., directed non-perpendicularly at (towards) the ground surface. For example, the third beam may be directed at an angle between the directions of the first and second beams.

[0054] In some examples, there may be one or more further (e.g., fourth, fifth , etc.) beams directed away; e.g., directed non-perpendicularly at (towards) the ground surface and at different angles between the directions of the first and second beams.

[0055] Each of the third / further beam(s) may be a relatively narrow beam (similar to the first and second beams) or a relatively wide beam.

[0056] The third / further beams may be used together with (and in a similar manner as) the first and second beams to determine at least one parameter of the motion of the vehicle in relation to the ground surface based on corresponding backscatter information. Using more beams for the motion estimation typically improves the determination (e.g., in terms of one or more of: accuracy, certainty, reliability, etc.).

[0057] Alternatively or additionally, the third / further beams may be used by the processing circuitry to detect objects other than ground surface based on the backscatter information. The objects may be any relevant objects in vicinity of the vehicle (e.g., other vehicles, pedestrians or other vulnerable road users, animals, infrastructural obstacles, etc.).

[0058] Generally, the approaches presented and exemplified herein may have the technical effect of improving accuracy and / or reducing cost compared to other approaches for vehicle motion estimation. For example, the suggested mounting of the radar transceiver(s) can (at least to large extent) avoid observing objects which are not part of the ground surface; thereby improving the estimation accuracy. For motion estimation using radar, it is typically preferable that the radar transceiver observes only stationary elements in the environment (e.g., ground surface) so that the observed Doppler velocity will be exclusively due to the ego-motion and enables efficient estimation of the unknown motion parameter(s). Therefore, the placement of the radar transceiver s) should preferably reduce the risk of the field of view being occluded by dynamic elements in the surroundings of the vehicle, which can be achieved by keeping the observed ground patch as close as possible to the vehicle body.

[0059] As already mentioned, an appropriate mounting of a radar transceiver to be used as described herein is in relation to (e.g., within the housing of) a side mirror of the vehicle. A benefit may include that the radar transceiver is mounted such that it can conveniently provide the two or more beams without obstruction by the vehicle. Alternatively or additionally, a benefit may include that the mounting of the radar transceiver causes no additional protrusions on the exterior of the vehicle. Yet alternatively or additionally, a benefit may include that the radar transceiver is protected against physical damages. Yet alternatively or additionally, a benefit may include that - since the side mirror is often located relatively high up on the vehicle - the risk of the radar transceiver bumping into obstacles in vicinity of the vehicle is reduced (thereby reducing alignment problems). Yet alternatively or additionally, a benefit may include that the side mirror - including the radar transceiver - can be assembled as an integrated module and / or separately from the main assembly of the vehicle. Yet alternatively or additionally, a benefit may include that the side mirror may be assembled (e.g., off-site) in two different versions - including the radar transceiver and without the radar transceiver - and the vehicle may be selectively assembled using either of the side mirror versions (e.g., depending on customer requests).

[0060] FIG. 2A schematically illustrates an example vehicle 200 for cargo transport where the techniques disclosed herein can be advantageously applied. The vehicle 200 comprises a truck / tractor / towing unit 210 configured to tow one or more trailer unit(s) 220 in a known manner.

[0061] The vehicle 200 comprises one or more radar transceiver(s) 230 (e.g., the radar transceivers 130, 140 of FIG. 1), each appropriately mounted on the vehicle (e.g., in the side mirrors) and configured to transmit two or more beams, receive backscatter from the ground surface caused by the two or more beams, and provide backscatter information to a computer system, as explained herein.

[0062] The vehicle 200 also comprises a computer system (e.g., the computer system 110 of FIG. 1), configured to determine at least one parameter of the motion of the vehicle in relation to the ground surface based on backscatter information received / acquired from the one or more radar transceiver(s) 230 as explained herein.

[0063] For example, the tractor unit 210 and / or the trailer unit(s) 220 may comprise a vehicle control unit (VCU) 290 configured to perform various vehicle control functions, such as vehicle motion management (VMM), power / energy management, etc. Any of one or moreVCU(s) 290 may be configured to determine at least one parameter of the motion of the vehicle in relation to the ground surface based on backscatter information received / acquired from the one or more radar transceiver(s) 230. Thus, the techniques disclosed herein may be performed by any of one or more VCU(s) 290 of the vehicle 200.

[0064] FIG. 2B is a schematic top view of an example vehicle 200 (e.g., the vehicle 200 of FIG. 2A). The vehicle 200 comprises a truck / tractor / towing unit 210 configured to tow one or more trailer unit(s) 220 in a known manner. A lateral extension of the vehicle 200 is illustrated by “y” and a longitudinal extension of the vehicle 200 is illustrated by “x”. The coordinate system spanned by the lateral and a longitudinal extensions of the vehicle 200 may be termed as a vehicle coordinate frame.

[0065] The vehicle 200 comprises one or more radar transceiver(s) 230-r, 230-1 (e.g., the radar transceivers 130, 140 of FIG. 1, compare with 230 of FIG. 2A), each appropriately mounted on the vehicle (e.g., in the side mirrors). Each of the radar transceivers 230-r, 230-1 is configured to transmit two or more beams, receive backscatter from the ground surface caused by the two or more beams, and provide backscatter information to a computer system, as explained herein.

[0066] The vehicle 200 also comprises a computer system (e.g., the computer system 110 of FIG. 1), configured to determine at least one parameter of the motion of the vehicle in relation to the ground surface based on backscatter information received / acquired from the one or more radar transceiver(s) 230-r, 230-1 as explained herein.

[0067] For example, the tractor unit 210 and / or the trailer unit(s) 220 may comprise a vehicle control unit (VCU) 290 configured to perform various vehicle control functions, such as vehicle motion management (VMM), power / energy management, etc. Any of one or more VCU(s) 290 may be configured to determine at least one parameter of the motion of the vehicle in relation to the ground surface based on backscatter information received / acquired from the one or more radar transceiver(s) 230-r, 230-1. Thus, the techniques disclosed herein may be performed by any of one or more VCU(s) 290 of the vehicle 200.

[0068] As illustrated in the example of FIG. 2B, each of the radar transceivers 230-r, 230-1 is configured to transmit a first beam 231-r, 231-1 directed rearwards along a side of the vehicle, and a second beam 232-r, 232-1 directed laterally across a front of the vehicle.

[0069] In some examples, one or more of the radar transceivers 230-r, 230-1 may be further configured to transmit a third beam directed away from the vehicle, which is exemplified by the relatively wide beams 233-r, 233-1.

[0070] The transmitted beams 231-r, 231-1, 232-r, 232-1 of the radar transceiver(s) 230-r, 230-1 are directed non-perpendicularly towards the ground surface, and can therefore be conveniently used to determine velocity over the ground surface of the vehicle 200 in a reliable manner.

[0071] For example, each beam may enable determination of a velocity over the ground surface as experienced by the radar transceiver that transmitted the beam, wherein the velocity has a direction that corresponds to the direction of the beam as projected on the plane which is perpendicular to the vertical extension of the vehicle. Combining information of the determined velocities for some / all beams transmitted by the two or more radar transceivers 230-r, 230-1 enables determination of various motion components of the vehicle 200 (e.g., longitudinal velocity vx, lateral velocity vy, and yaw rate mz).

[0072] FIG. 3A schematically illustrates an example tractor unit 210 comprising a radar transceiver 230 appropriately mounted on the vehicle (compare with FIGs. 2A, 2B). The radar transceiver 230 is configured to transmit at least first and second beams directed non- perpendicularly at the ground surface, wherein the first beam is directed rearwards along a side of the tractor unit 210 (compare with 231-1 of FIG. 2B) and the second beam is directed laterally across a front of the tractor unit 210 (compare with 232-1 of FIG. 2B).

[0073] The direction of the first beam is illustrated by 380, and it can be seen that it is non-perpendicular to the ground surface since it has an angle a 385 relative a plane which is perpendicular to the vertical extension of the vehicle, wherein the angle 385 has a magnitude which is larger than zero degrees and less than 90 degrees.

[0074] The radar transceiver 230 is also configured to receive backscatter from the ground surface caused by the transmitted beam, and provide backscatter information to a computer system, for determination of at least one parameter of the vehicle motion in relation to the ground surface. Particularly, the backscatter information related to the first beam enables determination of the longitudinal velocity vx320 of the tractor unit 210.

[0075] As will be described more thoroughly herein, the backscatter provides information relating to Doppler velocity and range between the radio transceiver 230 and the groundsurface. Generally, the Doppler velocity may be defined as relative velocity between the radio transceiver 230 and the ground surface, estimated based on the Doppler shift of the backscatter compared to the transmitted beam.

[0076] FIG. 3B schematically illustrates an example vehicle 200 comprising a tractor unit 210 and a towed trailer unit 220 (compare with FIGs. 2A, 2B, 3A). A lateral extension of the vehicle 200 is illustrated by “y” and a longitudinal extension of the vehicle 200 is illustrated by “x”; spanning the vehicle coordinate frame.

[0077] The vehicle 200 comprises two radar transceivers 230-r, 230-1 appropriately mounted on the vehicle 200, and FIG. 3B exemplifies some components of the vehicle geometry in relation to the vehicle coordinate frame. The velocity of the vehicle 200 is represented by 310 (and can be seen as spanned by the longitudinal velocity vxof the vehicle 200 which is represented by 320 and the lateral velocity vyof the vehicle 200 which is represented by 330), and the yaw rate mzof the vehicle 200 is represented by 370.

[0078] The position of the radar transceiver 230-r in the vehicle coordinate frame is represented by 360 and a beam direction of the radar transceiver 230-r is represented by 350. It should be noted that the beam direction 350 may be compared to the direction of any of the beams 231-r, 232-r, 233-r of FIG. 2B. Corresponding statements may be provided for the radar transceiver 230-1.

[0079] For the example of FIG. 3A, the Doppler velocity v of the backscatter may be expressed as v = cos(cr) vx+ ev, where evrepresents noise (e.g., with Gaussian distribution at zero mean and variance <JV2).

[0080] When the radar transceiver observes stationary elements in the environment (e.g., the ground surface), the resulting Doppler velocity observations will be due to the ego-motion of the vehicle and it is possible to effectively estimate unknown motion variables (components, parameters) of the vehicle. To this end, the radar transceiver s) are preferably placed to avoid that the field of view is occluded by dynamic elements in the surroundings of the vehicle. This can be achieved by keeping the observed patch of the ground surface as close as possible to the vehicle body (compare with beams 231-r, 231-1, 232-r, 232-1 of the radar transceiver(s) 230-r, 230-1 in FIG. 2B).

[0081] The magnitude of the angle a 385 should preferably be selected to be sufficiently lower than 90 degrees since a relatively large angle magnitude tends to result in a relativelypoor (low) signal-to-noise ratio (SNR), which in turn degrades the estimation performance for the motion components of the vehicle.

[0082] For the example of FIG. 3B, the Doppler velocity Vj observed along the corresponding observation axis j (the axis spanned by 350) will be due to a combination of all motion components vx, vy, )z. Using kinematics knowledge, the Doppler velocity can be expressed as Vjrepresents a unitlength observation vector along the observation axis j and [cxcy] represents the position 360 of the radar transceiver 230-r in the vehicle coordinate frame. This can be expressed via the linear relation= x between the Doppler velocity and a state vector x = [vxvya>z]T.

[0083] Observing the Doppler velocities along several different observation axes j = 1 ... N (compare with beams 231-r, 231-1, 232-r, 232-1 of FIG. 2B) yields an extended linear model v = Cx, where v = [vx... vN]T, which can be solved using any suitable approach for solving linear equation systems to achieve x.

[0084] Adding more observation axes, e.g., directed away from the vehicle (compare with beams 233-r, 233-1 of FIG. 2B), can improve the result; e.g., in terms of increased accuracy and / or certainty information.

[0085] To obtain reasonably reliable Doppler velocity estimates for a beam that is directed away from the vehicle, it is beneficial to be able to identify (and remove or ignore) backscatter that is not caused by the ground surface. This can be achieved by applying a spatial filter to the backscatter wherein the spatial filter corresponds to an expected backscatter pattern if there was only ground surface in the field of view of the beam. The filter can be refined so that it corresponds to only an expected velocity range (e.g., a velocity range derived based on the velocity estimations of beams directed very close to the vehicle).

[0086] Other motion components of the vehicle include pitch angle (p and roll angle 0 (vehicle pose). For example, the beams 231-r, 231-1 may be used to determine pitch angle (p of the vehicle and the beams 232-r, 232-1 may be used to determine roll angle 0 of the vehicle. With reference to FIG. 3A, the pitch angle may be achieved by using the expressions v = cos(a + <p) vxand (h — Z?)cos(<p) — I sin(<p) + R = r sin(<z + <p) for given values of vx, h, R, and Z, where h represents the height over ground of the radar transceiver, I represents the horizontal distance between the radar transceiver and the font wheel axle, and R represents front wheel radius, and correspondingly for the roll angle. To this end, it istypically beneficial if the range measurements are relatively sensitive to changes in the pose (relatively small change in pitch / roll angle leading to a relatively large change in range). This can be achieved by using a relatively small elevation angle a for the first beam (relating to the pitch angle; compare with 385 of FIG. 3A) and / or for the second beam (relating to the roll angle).

[0087] FIG. 4A schematically illustrates example backscatter information 400, caused by transmission of a beam directed non-perpendicularly towards the ground surface (compare with beams 231-r, 231-1, 232-r, 232-1 of the radar transceiver(s) 230-r, 230-1 in FIG. 2B). The backscatter is represented by backscatter power distribution 403 for different values of range 401 from the radar transceiver to the reflecting surface and for different values of registered Doppler velocity 402.

[0088] FIG. 4A illustrates an example range-Doppler power spectrum 400 from a real- world radar transceiver. The expected range-Doppler appearance (i.e., the expected backscatter pattern) corresponds to a bent curve in the range-Doppler plane. The artefact 404 around zero range and zero Doppler is most likely due to near-field effects and can be ignored for the purposes herein.

[0089] FIG. 4B schematically illustrates some example backscatter patterns 410, 420, 430, 440 in a coordinate system spanned by range 401 from the radar transceiver to the reflecting surface and registered Doppler velocity 402, as expected by transmission of a beam directed non-perpendicularly towards the ground surface (compare with FIG. 4A). It may be noted that each expected backscatter pattern 410, 420, 430, 440 exhibits a similar shape; a bent (banana-like) curve in the range-Doppler plane.

[0090] The example expected backscatter patterns 410, 420, 430, 440 relate to different velocities over the ground surface as experienced by the radar transceiver that transmitted the beam. As the range 401 increases, each curve approaches a Doppler velocity 402 which corresponds to the velocity experienced by the radar transceiver in the direction of the transmitted beam as projected on the plane which is perpendicular to the vertical extension of the vehicle, as illustrated by 411, 421, 431, 441. When the range 401 approaches the height over ground of the radar transceiver (i.e., backscatter components perpendicular to the ground surface), each curve approaches zero Doppler velocity 402-0, as illustrated by 450.

[0091] Thus, when a transmitted beam of a radar transceiver is directed non- perpendicularly towards the ground surface, the backscatter it causes can be convenientlyused to determine velocity over the ground surface as experienced by the radar transceiver. Particularly, mapping the range-Doppler power spectrum 400 of the backscatter to a corresponding expected backscatter pattern 410, 420, 430, 440 renders a value of the velocity 411, 421, 431, 441 of the over the ground surface as experienced by the radar transceiver in the direction of the transmitted beam as projected on the plane which is perpendicular to the vertical extension of the vehicle (compare with the Doppler velocity Vj observed along the corresponding observation axis j as explained in relation to FIG. 3B).

[0092] Generally, a beam of the radar transceiver typically illuminates an area on the ground surface rather than a small point. Thus, backscatter from different observation directions is simultaneously collected. This means that there will be a spread in the elevation angle a and the azimuth angle [J in the transmitted beam, which results in the variations in range and Doppler velocity as exemplified by FIG. 4A.

[0093] Referring to the example of FIG. 3A, the expected backscatter pattern is derivable by varying a and fl in the expressions v = cos(cr) cos P') vxand h = r sin a for given values of vxand h, where h represents the height over ground of the radar transceiver. Thus, the expected backscatter pattern can be determined analytically. There are, however, also other ways to determine the expected backscatter pattern given a certain vehicle motion over the surface supporting the vehicle. One such method is an experimental method where the vehicle is moved over the surface at a known motion state (known velocity etc.) and the range-Doppler appearance is recorded a few times, averaged, and then stored in a database indexed by vehicle motion state. This database can then be consulted if an expected backscatter pattern for a given motion state is wanted.

[0094] An expected backscatter pattern (an expected range-Doppler appearance) can, according to the teachings herein, be formatted in different ways. According to one example the expected range-Doppler appearance is formatted as a curve in the range-Doppler plane, i.e., as a function v = f(r According to another example the expected range-Doppler appearance is a discrete set of magnitudes indexed by range r and by velocity v, i.e., similar to a fast Fourier transform based discrete range-Doppler map obtained from a radar transceiver. According to yet another example the expected range-Doppler appearance is a continuous three-dimensional function which indicates expected power (possibly with phase) over range r and velocity v.

[0095] The expected range-Doppler appearance can be used by a computer system (e.g., one or more VCUs) to define one or more spatial range-Doppler filters that can be applied to the range-Doppler data obtained from the one or more radar transceivers. Referring to FIG. 4B, a spatial filter may be configured to pass only signals associated with (e.g., in a region in close vicinity to) the expected pattern 410, 420, 430, 440 of a particular velocity 411, 421, 431, 441, which may be beneficial to remove backscatter that is not caused by the ground surface. Alternatively or additionally, a spatial filter may be configured to block signals associated with the expected pattern 410, 420, 430, 440 of a particular velocity 411, 421, 431, 441, which may be beneficial to detect objects other than ground surface based on the backscatter information. Other types of filters may be equally applicable (e.g., filters with graded edges). Thus, spatial filters may be configured to separate backscatter of the ground surface from backscatter of objects other than ground surface.

[0096] For a particular beam, the corresponding Doppler velocity may be identified by mapping the backscatter information to the expected backscatter pattern which is considered to have best resemblance with the backscatter information. For example, this can be achieved by applying spatial filters for different velocities and selecting the velocity that yields the highest signal power at the filter output.

[0097] FIG. 5 illustrates an example method 500 for determining motion of a vehicle in relation to a ground surface. For example, the method 500 may be performed by the arrangement 100 of FIG. 1 and / or by the vehicle 200 of FIGs. 2A, 2B. Thus, the arrangement 100 of FIG. 1 and / or the vehicle 200 of FIGs. 2A, 2B may be configured to perform, or cause performance of, one or more steps of the method 500.

[0098] As illustrated by step 510, two or more beams are transmitted by each of one or more radar transceivers mounted on the vehicle. The two or more beams are directed non- perpendicularly at (towards) the ground surface. A first beam of the two or more beams is directed rearwards along a side of the vehicle, and a second beam of the two or more beams is directed laterally across a front of the vehicle.

[0099] As illustrated by step 520, backscatter from the ground surface - caused by the two or more beams - is received by each of the one or more radar transceivers.

[0100] As illustrated by step 530, backscatter information is provided by the one or more radar transceivers to a computer system comprising processing circuitry.

[0101] As illustrated by step 540, at least one parameter of the motion of the vehicle in relation to the ground surface is determined by the processing circuitry based on the backscatter information.

[0102] FIG. 6 illustrates an example computer-implemented method 600 for determining motion of a vehicle in relation to a ground surface by a computer system comprising processing circuitry. For example, the method 600 may be performed by the computer system 110 of FIG. 1 and / or by the VCU 290 of FIGs. 2A, 2B. Thus, the computer system 110 of FIG. 1 and / or the VCU 290 of FIGs. 2A, 2B may be configured to perform, or cause performance of, one or more steps of the method 600.

[0103] As illustrated by steps 630 and 640 (compare with steps 530 and 540 of FIG. 5), the processing circuitry acquires backscatter information from one or more radar transceivers, and determines at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information.

[0104] Generally, any measurements acquired using the approaches described herein (and / or parameter values derived therefrom) may be used in combination with measurements from a vehicle inertial measurement unit (IMU). For example, pitch / roll angle estimations may be used directly together with angular rate measurements collected from gyroscopes of the IMU (e.g., comprising all of them in a measurement vector related to a system of linear equations for motion estimation or other purposes). Alternatively or additionally, acceleration measurements from the IMU may undergo integration to obtain velocity values, which may be combined in any suitable way with the velocities as estimated using radar transceivers.

[0105] FIG. 7 is a schematic diagram of a computer system 700 for implementing examples disclosed herein. The computer system 700 is adapted to execute instructions from a computer-readable medium to perform these and / or any of the functions or processing described herein. The computer system 700 may be connected (e.g., networked) to other machines in a LAN (Local Area Network), LIN (Local Interconnect Network), automotive network communication protocol (e.g., FlexRay), an intranet, an extranet, or the Internet. While only a single device is illustrated, the computer system 700 may include any collection of devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. Accordingly, any reference in the disclosure and / or claims to a computer system, computing system, computer device, computing device, control system, control unit, electronic control unit (ECU), processordevice, processing circuitry, etc., includes reference to one or more such devices to individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. For example, control system may include a single control unit or a plurality of control units connected or otherwise communicatively coupled to each other, such that any performed function may be distributed between the control units as desired. Further, such devices may communicate with each other or other devices by various system architectures, such as directly or via a Controller Area Network (CAN) bus, etc.

[0106] The computer system 700 may comprise at least one computing device or electronic device capable of including firmware, hardware, and / or executing software instructions to implement the functionality described herein. The computer system 700 may include processing circuitry 702 (e.g., processing circuitry including one or more processor devices or control units), a memory 704, and a system bus 706. The computer system 700 may include at least one computing device having the processing circuitry 702. The system bus 706 provides an interface for system components including, but not limited to, the memory 704 and the processing circuitry 702. The processing circuitry 702 may include any number of hardware components for conducting data or signal processing or for executing computer code stored in memory 704. The processing circuitry 702 may, for example, include a general-purpose processor, an application specific processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a circuit containing processing components, a group of distributed processing components, a group of distributed computers configured for processing, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processing circuitry 702 may further include computer executable code that controls operation of the programmable device.

[0107] The system bus 706 may be any of several types of bus structures that may further interconnect to a memory bus (with or without a memory controller), a peripheral bus, and / or a local bus using any of a variety of bus architectures. The memory 704 may be one or more devices for storing data and / or computer code for completing or facilitating methods described herein. The memory 704 may include database components, object code components, script components, or other types of information structure for supporting thevarious activities herein. Any distributed or local memory device may be utilized with the systems and methods of this description. The memory 704 may be communicably connected to the processing circuitry 702 (e.g., via a circuit or any other wired, wireless, or network connection) and may include computer code for executing one or more processes described herein. The memory 704 may include non-volatile memory 708 (e.g., read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.), and volatile memory 710 (e.g., randomaccess memory (RAM)), or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a computer or other machine with processing circuitry 702. A basic input / output system (BIOS) 712 may be stored in the non-volatile memory 708 and can include the basic routines that help to transfer information between elements within the computer system 700.

[0108] The computer system 700 may further include or be coupled to a non-transitory computer-readable storage medium such as the storage device 714, which may comprise, for example, an internal or external hard disk drive (HDD) (e.g., enhanced integrated drive electronics (EIDE) or serial advanced technology attachment (SATA)), HDD (e.g., EIDE or SATA) for storage, flash memory, or the like. The storage device 714 and other drives associated with computer-readable media and computer-usable media may provide nonvolatile storage of data, data structures, computer-executable instructions, and the like.

[0109] Computer-code which is hard or soft coded may be provided in the form of one or more modules. The module(s) can be implemented as software and / or hard-coded in circuitry to implement the functionality described herein in whole or in part. The modules may be stored in the storage device 714 and / or in the volatile memory 710, which may include an operating system 716 and / or one or more program modules 718. All or a portion of the examples disclosed herein may be implemented as a computer program 720 stored on a transitory or non-transitory computer-usable or computer-readable storage medium (e.g., single medium or multiple media), such as the storage device 714, which includes complex programming instructions (e.g., complex computer-readable program code) to cause the processing circuitry 702 to carry out actions described herein. Thus, the computer-readable program code of the computer program 720 can comprise software instructions for implementing the functionality of the examples described herein when executed by theprocessing circuitry 702. In some examples, the storage device 714 may be a computer program product (e.g., readable storage medium) storing the computer program 720 thereon, where at least a portion of a computer program 720 may be loadable (e.g., into a processor) for implementing the functionality of the examples described herein when executed by the processing circuitry 702. The processing circuitry 702 may serve as a controller or control system for the computer system 700 that is to implement the functionality described herein.

[0110] The computer system 700 may include an input device interface 722 configured to receive input and selections to be communicated to the computer system 700 when executing instructions, such as from a keyboard, mouse, touch-sensitive surface, etc. Such input devices may be connected to the processing circuitry 702 through the input device interface 722 coupled to the system bus 706 but can be connected through other interfaces, such as a parallel port, an Institute of Electrical and Electronic Engineers (IEEE) 1394 serial port, a Universal Serial Bus (USB) port, an IR interface, and the like. The computer system 700 may include an output device interface 724 configured to forward output, such as to a display, a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)). The computer system 700 may include a communications interface 726 suitable for communicating with a network as appropriate or desired.

[0111] According to some examples, the computer system 700 may be suitable for determining motion of a vehicle in relation to a ground surface as described herein.

[0112] For example, the computer system 700 may be configured to perform, or cause performance of, one or more steps of the method 500 of FIG. 5 and / or the method 600 of FIG. 6. Alternatively or additionally, the computer system 700 may be comprised in, or comprise, one or more VCU(s) (e.g., the VCU 290 of FIGs. 2A and 2B). Yet alternatively or additionally, the computer system 700 may be comprised in a vehicle (e.g., the vehicle 200 of FIGs. 2A and 2B). Yet alternatively or additionally, the computer system 700 may implement the computer system 110 of FIG. 1.

[0113] The operational actions described in any of the exemplary aspects herein are described to provide examples and discussion. The actions may be performed by hardware components, may be embodied in machine-executable instructions to cause a processor to perform the actions, or may be performed by a combination of hardware and software. Although a specific order of method actions may be shown or described, the order of theactions may differ. In addition, two or more actions may be performed concurrently or with partial concurrence.

[0114] The described examples and their equivalents may be realized in software or hardware or a combination thereof. The examples may be performed by general purpose circuitry. Examples of general purpose circuitry include digital signal processors (DSP), central processing units (CPU), co-processor units, field programmable gate arrays (FPGA) and other programmable hardware. Alternatively or additionally, the examples may be performed by specialized circuitry, such as application specific integrated circuits (ASIC). The general purpose circuitry and / or the specialized circuitry may, for example, be associated with or comprised in an electronic apparatus such as a vehicle control unit (VCU) or other suitable control unit.

[0115] The electronic apparatus may comprise arrangements, circuitry, and / or logic according to any of the examples described herein. Alternatively or additionally, the electronic apparatus may be configured to perform method steps according to any of the examples described herein.

[0116] According to some examples, a computer program product comprises a non- transitory computer readable medium such as, for example, a universal serial bus (USB) memory, a plug-in card, an embedded drive, or a read only memory (ROM). FIG. 8 illustrates a computer program product 800 exemplified as a non-transitory computer- readable medium in the form of a compact disc (CD) ROM. The computer-readable medium has stored thereon program code 840 comprising instructions. The program code is loadable into processing circuitry (PROC; e.g., a data processing unit) 820, which may, for example, be comprised in a processing unit 810. When loaded into the processing circuitry, the program code may be stored in a memory (MEM) 830 associated with, or comprised in, the processing circuitry. According to some examples, the program code may, when loaded into, and run by, the processing circuitry, cause execution of method steps according to, for example, any of the methods described herein.

[0117] FIG. 9 schematically illustrates, in terms of a number of functional units, the components of a control unit 900 according to some examples. This control unit 900 may be comprised in the vehicle 200; e.g., in the form of a VCU 290 (compare with FIGs. 2A and 2B). Processing circuitry 910 is provided using any combination of one or more of a suitable central processing unit CPU, multiprocessor, microcontroller, digital signal processor DSP,etc., capable of executing software instructions stored in a computer program product, e.g. in the form of a storage medium 930. The processing circuitry 910 may further be provided as at least one application specific integrated circuit ASIC, or field programmable gate array FPGA.

[0118] Particularly, the processing circuitry 910 is configured to cause the control unit 800 to perform a set of operations, or steps, such as any of the methods discussed in connection to FIGs. 5 and 6.

[0119] For example, the storage medium 930 may store the set of operations, and the processing circuitry 910 may be configured to retrieve the set of operations from the storage medium 930 to cause the control unit 900 to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus, the processing circuitry 910 is thereby arranged to execute methods as herein disclosed. In particular, there is disclosed a control unit 900 for controlling an articulated vehicle 200 comprising a tractor 210 and / or one or more towed vehicle units 220, the control unit comprising processing circuitry 910, an interface 920 coupled to the processing circuitry 910, and a memory 930 coupled to the processing circuitry 910, wherein the memory comprises machine readable computer program instructions that, when executed by the processing circuitry, causes the control unit to perform the methods discussed herein.

[0120] The storage medium 930 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

[0121] The control unit 900 may further comprise an interface 920 for communications with at least one external device. As such, the interface 920 may comprise one or more transmitters and receivers, comprising analogue and digital components and a suitable number of ports for wireline or wireless communication.

[0122] The processing circuitry 910 controls the general operation of the control unit 900, e.g., by sending data and control signals to the interface 920 and the storage medium 930, by receiving data and reports from the interface 920, and by retrieving data and instructions from the storage medium 930. Other components, as well as the related functionality, of the control node are omitted in order not to obscure the concepts presented herein.A non-exhaustive list of examples:

[0123] Example 1: An arrangement for determining motion of a vehicle in relation to a ground surface, the arrangement comprising a computer system comprising processing circuitry, and one or more radar transceivers mountable on the vehicle, wherein each radar transceiver is configured to transmit two or more beams directed non-perpendicularly at the ground surface, receive backscatter from the ground surface caused by the two or more beams, and provide backscatter information to the computer system, wherein a first beam of the two or more beams is directed rearwards along a side of the vehicle, and a second beam of the two or more beams is directed laterally across a front of the vehicle, and wherein the processing circuitry is configured to determine at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information.

[0124] Example 2: The arrangement of Example 1, wherein the at least one parameter of the motion of the vehicle in relation to the ground surface comprises one or more of: a lateral speed of the vehicle in relation to the ground surface, a longitudinal speed of the vehicle in relation to the ground surface, and a yaw rate of the vehicle in relation to the ground surface.

[0125] Example 3: The arrangement of any of Examples 1-2, wherein the processing circuitry is configured to determine the at least one parameter of the motion of the vehicle in relation to the ground surface by matching the backscatter information to an expected backscatter pattern, wherein the expected backscatter pattern is indicative of a corresponding possible motion of the vehicle in relation to the ground surface.

[0126] Example 4: The arrangement of any of Examples 1-3, wherein each radar transceiver is configured to be comprised in a respective side mirror of the vehicle.

[0127] Example 5: The arrangement of any of Examples 1-4, wherein the two or more beams of at least one of the radar transceivers comprises at least a third beam directed away from the vehicle.

[0128] Example 6: The arrangement of Example 5, wherein the processing circuitry is further configured to detect objects other than ground surface based on the backscatter information.

[0129] Example 7: The arrangement of Example 6, wherein the processing circuitry is configured to detect objects other than ground surface by applying a spatial filter to the backscatter information, wherein the spatial filter is configured to separate backscatter of the ground surface from backscatter of objects other than ground surface.

[0130] Example 8: A computer system for determining motion of a vehicle in relation to a ground surface, the computer system comprising processing circuitry configured to acquire backscatter information from one or more radar transceivers mountable on the vehicle, and determine at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information, wherein the backscatter information from each radar transceiver is based on backscatter from the ground surface caused by two or more beams transmitted by the radar transceiver and directed non-perpendicularly at the ground surface, and wherein a first beam of the two or more beams is directed rearwards along a side of the vehicle, and a second beam of the two or more beams is directed laterally across a front of the vehicle.

[0131] Example 9: The computer system of Example 8, wherein the at least one parameter of the motion of the vehicle in relation to the ground surface comprises one or more of: a lateral speed of the vehicle in relation to the ground surface, a longitudinal speed of the vehicle in relation to the ground surface, and a yaw rate of the vehicle in relation to the ground surface.

[0132] Example 10: The computer system of any of Examples 8-9, wherein the processing circuitry is configured to determine the at least one parameter of the motion of the vehicle in relation to the ground surface by matching the backscatter information to an expected backscatter pattern, wherein the expected backscatter pattern is indicative of a corresponding possible motion of the vehicle in relation to the ground surface.

[0133] Example 11: The computer system of any of Examples 8-10, wherein the two or more beams of at least one of the radar transceivers comprises at least a third beam directed away from the vehicle.

[0134] Example 12: The computer system of Example 11, wherein the processing circuitry is further configured to detect objects other than ground surface based on the backscatter information.

[0135] Example 13: The computer system of Example 12, wherein the processing circuitry is configured to detect objects other than ground surface by applying a spatial filter to the backscatter information, wherein the spatial filter is configured to separate backscatter of the ground surface from backscatter of objects other than ground surface.

[0136] Example 14: A vehicle comprising the arrangement according to any of Examples 1-7 and / or the computer system of any of Examples 8-13.

[0137] Example 15: A method for determining motion of a vehicle in relation to a ground surface, the method comprising transmitting (by one or more radar transceivers mounted on the vehicle) two or more beams directed non-perpendicularly at the ground surface, wherein a first beam of the two or more beams is directed rearwards along a side of the vehicle, and a second beam of the two or more beams is directed laterally across a front of the vehicle, receiving (by the one or more radar transceivers) backscatter from the ground surface caused by the two or more beams, providing (by the one or more radar transceivers) backscatter information to a computer system comprising processing circuitry, and determining (by the processing circuitry) at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information.

[0138] Example 16: A computer-implemented method for determining motion of a vehicle in relation to a ground surface, the method comprising acquiring (by processing circuitry of a computer system) backscatter information from one or more radar transceivers mountable on the vehicle, and determining (by the processing circuitry) at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information, wherein the backscatter information from each radar transceiver is based on backscatter from the ground surface caused by two or more beams transmitted by the radar transceiver and directed non-perpendicularly at the ground surface, and wherein a first beam of the two or more beams is directed rearwards along a side of the vehicle, and a second beam of the two or more beams is directed laterally across a front of the vehicle.

[0139] Example 17: The method of any of Examples 15-16, wherein the at least one parameter of the motion of the vehicle in relation to the ground surface comprises one or more of: a lateral speed of the vehicle in relation to the ground surface, a longitudinal speed of the vehicle in relation to the ground surface, and a yaw rate of the vehicle in relation to the ground surface.

[0140] Example 18: The method of any of Examples 15-17, wherein determining the at least one parameter of the motion of the vehicle in relation to the ground surface comprises matching the backscatter information to an expected backscatter pattern, wherein the expected backscatter pattern is indicative of a corresponding possible motion of the vehicle in relation to the ground surface.

[0141] Example 19: The method of any of Examples 15-18, wherein the two or more beams of at least one of the radar transceivers comprises at least a third beam directed away from the vehicle.

[0142] Example 20: The method of Example 19, further comprising detecting objects other than ground surface based on the backscatter information.

[0143] Example 21: The method of Example 20, wherein detecting objects other than ground surface comprises applying a spatial filter to the backscatter information, wherein the spatial filter is configured to separate backscatter of the ground surface from backscatter of objects other than ground surface.

[0144] Example 22: A computer program product comprising program code for performing, when executed by the processing circuitry, the method of any of Examples 15- 21

[0145] Example 23: A non-transitory computer-readable storage medium comprising instructions, which when executed by the processing circuitry, cause the processing circuitry to perform the method of any of Examples 15-21.

[0146] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0147] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

[0148] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element to another elementas illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0149] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0150] It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.

Claims

ClaimsWhat is claimed is:

1. An arrangement (100) for determining motion of a vehicle (200) in relation to a ground surface, the arrangement comprising a computer system (110, 290, 700) comprising processing circuitry (120), and one or more radar transceivers (130, 140, 230, 230-r, 230-1) mountable on the vehicle, wherein each radar transceiver (130, 140, 230, 230-r, 230-1) is configured to transmit two or more beams (231-r, 232-r, 233-r, 231-1, 232-1, 233-1) directed non- perpendicularly at the ground surface, receive backscatter from the ground surface caused by the two or more beams (231-r, 232-r, 233-r, 231-1, 232-1, 233-1), and provide backscatter information (400) to the computer system (110, 290, 700), wherein a first beam (231-r, 231-1) of the two or more beams is directed rearwards along a side of the vehicle (200), and a second beam (232-r, 232-1) of the two or more beams is directed laterally across a front of the vehicle (200), and wherein the processing circuitry (120) is configured to determine at least one parameter of the motion of the vehicle (200) in relation to the ground surface based on the backscatter information.

2. The arrangement of claim 1, wherein the at least one parameter of the motion of the vehicle in relation to the ground surface comprises one or more of: a lateral speed (330) of the vehicle in relation to the ground surface; a longitudinal speed (320) of the vehicle in relation to the ground surface; and a yaw rate (370) of the vehicle in relation to the ground surface.

3. The arrangement of any of claims 1-2, wherein the processing circuitry is configured to determine the at least one parameter of the motion of the vehicle in relation to the ground surface by matching the backscatter information to an expected backscatter pattern (410, 420, 430, 440), wherein the expected backscatter pattern is indicative of a corresponding possible motion (350) of the vehicle in relation to the ground surface.

4. The arrangement of any of claims 1-3, wherein each radar transceiver is configured to be comprised in a respective side mirror of the vehicle.

5. The arrangement of any of claims 1-4, wherein the two or more beams of at least one of the radar transceivers comprises at least a third beam (233-r, 233-1) directed away from the vehicle.

6. The arrangement of claim 5, wherein the processing circuitry is further configured to detect objects other than ground surface based on the backscatter information.

7. The arrangement of claim 6, wherein the processing circuitry is configured to detect objects other than ground surface by applying a spatial filter to the backscatter information, wherein the spatial filter is configured to separate backscatter of the ground surface from backscatter of objects other than ground surface.

8. A computer system (110, 290, 700) for determining motion of a vehicle (200) in relation to a ground surface, the computer system comprising processing circuitry (120) configured to: acquire backscatter information (400) from one or more radar transceivers (130, 140, 230, 230-r, 230-1) mountable on the vehicle; and determine at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information, wherein the backscatter information from each radar transceiver (130, 140, 230, 230-r, 230-1) is based on backscatter from the ground surface caused by two or more beams (231-r, 232-r, 233-r, 231-1, 232-1, 233-1) transmitted by the radar transceiver and directed non-perpendicularly at the ground surface, and wherein a first beam (231-r, 231-1) of the two or more beams is directed rearwards along a side of the vehicle (200), and a second beam (232-r, 232-1) of the two or more beams is directed laterally across a front of the vehicle (200).

9. The computer system of claim 8, wherein the processing circuitry is configured to determine the at least one parameter of the motion of the vehicle in relation to the groundsurface by matching the backscatter information to an expected backscatter pattern (410, 420, 430, 440), wherein the expected backscatter pattern is indicative of a corresponding possible motion (350) of the vehicle in relation to the ground surface.

10. A vehicle (200) comprising the arrangement (100) according to any of claims 1-7 and / or the computer system (110, 290, 700) of any of claims 8-9.

11. A method (500) for determining motion of a vehicle (200) in relation to a ground surface, the method comprising: transmitting (510), by one or more radar transceivers (130, 140, 230, 230-r, 230-1) mounted on the vehicle, two or more beams (231-r, 232-r, 233-r, 231-1, 232-1, 233-1) directed non-perpendicularly at the ground surface, wherein a first beam (231-r, 231-1) of the two or more beams is directed rearwards along a side of the vehicle (200), and a second beam (232- r, 232-1) of the two or more beams is directed laterally across a front of the vehicle (200); receiving (520), by the one or more radar transceivers, backscatter from the ground surface caused by the two or more beams; providing (530), by the one or more radar transceivers, backscatter information (400) to a computer system comprising processing circuitry; and determining (540), by the processing circuitry, at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information.

12. A computer-implemented method (600) for determining motion of a vehicle (200) in relation to a ground surface, the method comprising: acquiring (630), by processing circuitry of a computer system, backscatter information (400) from one or more radar transceivers (130, 140, 230, 230-r, 230-1) mountable on the vehicle; and determining (640), by the processing circuitry, at least one parameter of the motion of the vehicle in relation to the ground surface based on the backscatter information, wherein the backscatter information from each radar transceiver is based on backscatter from the ground surface caused by two or more beams (231-r, 232-r, 233-r, 231-1, 232-1, 233-1) transmitted by the radar transceiver and directed non-perpendicularly at the ground surface, andwherein a first beam (231-r, 231-1) of the two or more beams is directed rearwards along a side of the vehicle (200), and a second beam (232-r, 232-1) of the two or more beams is directed laterally across a front of the vehicle (200).

13. The method of any of claims 11-12, wherein determining the at least one parameter of the motion of the vehicle in relation to the ground surface comprises matching the backscatter information to an expected backscatter pattern (410, 420, 430, 440), wherein the expected backscatter pattern is indicative of a corresponding possible motion (350) of the vehicle in relation to the ground surface.

14. A computer program product (800) comprising program code (840) for performing, when executed by the processing circuitry, the method of any of claims 11-13.

15. A non-transitory computer-readable storage medium (800) comprising instructions, which when executed by the processing circuitry, cause the processing circuitry to perform the method of any of claims 11-13.

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