Multi-directional transducer system

Abstract

An obstacle sensing system in or on a host carrier, the obstacle sensing system comprising at least two sensor devices (34), each sensor device (34) comprising a base (16) unit having in or on a planar outer surface thereof first, second and third transducer arrays (10, 12, 14), each transducer array (10, 12, 14) comprising a plurality of active transducer elements, one or more of which are transmitters and another or more of which are receivers, the first, second and third transducer arrays (10, 12, 14) being arranged along said planar outer surface of said base (16), in side by side and spaced apart relation, such that said second transducer array (12) is substantially central and the first and third transducer arrays (10), (14) are located on either side of said second transducer element (12), the sensor device (34) further comprising a first reflector plate (18) mounted in relation to said first transducer array (10) at substantially 135° relative to said planar outer surface of the base unit (16), and a second reflector plate (20), mounted in relation to said third transducer array (14) at substantially 45° to said planar outer surface of the base unit (16), such that, in use, waveform beams (28, 30, 32) emitted by the first, second and third transducer arrays (10, 12, 14) cover a 270° region around said sensor device (34), the obstacle sensing system further comprising an analysis module for receiving and analysing reflected signals received by transducer elements of one or more of said transducer arrays (10, 12, 14) to generate target data and identify thereby obstacles in the vicinity thereof, said at least two sensor devices (34) being arranged and configured in or on said host carrier such that the beams (28, 20, 32) formed by the transducer elements of the transducer arrays (10, 12, 14) thereof at least partially overlap to provide at least bifocal / bistatic sensor coverage around a peripheral region of said host carrier.

Description

[0001] MULTI-DIRECTIONAL TRANSDUCER SYSTEM

[0002] Field of the Invention

[0003] This invention relates generally to a multi-directional transducer system and, more particularly, but not necessarily exclusively, to a sensor device and an improved beamforming and sensing system for high-resolution, omni-directional surround sensing systems, particularly (but again not necessarily exclusively) suitable for use in automated driving systems (ADS) or advanced driver-assisted systems (ADAS).

[0004] Background of the Invention

[0005] References throughout the following description and claims to an ‘antenna’ are intended to include any beamforming and / lor imaging transducer suitable for use in, for example, radio frequency (RF), optical, sonar, and ultrasonic applications, and the present invention is not necessarily intended to be limited in his regard. Accordingly, the terms ‘antenna’ and ‘transducer’ may be used interchangeably herein, without limitation.

[0006] Antenna and other transducer systems are well known in various fields of technology, for receiving and transmitting mechanical (pressure) and electromagnetic waves. The configurations of such systems vary greatly, depending on the waves in question and the field of application, as well as the performance metrics to be achieved. Examples of such systems can, for example, be found in the field of millimetre waves that utilise electromagnetic waves of frequency 30 - 300GHz in a wide range of applications, including radio astronomy, remote sensing, imaging, security screening, telecommunications, military systems and automotive radar. Many of these, and other real-world systems require effective multi-directional or even omnidirectional (360°) operation in near real time in order to meet the requirements of the application. This functionality can, in theory at least, be attained by scanning (i.e. rotating the antenna about an axis to capture signals from a 360° volume surrounding it). However, in practice, such systems are impractical for many applications, including vehicular monitoring and / or imaging applications (such as automotive radar), as the environment surrounding the antenna changes too quickly to be captured and processed sufficiently quickly and at a sufficiently high resolution. Furthermore, the usage of electromechanical parts like motors and drive assemblies have cost, size, weight and power implications, and are often impractical for use in applications such as vehicular monitoring simply from a logistic perspective in that they cannot be easily incorporated into a vehicle body.

[0007] There is a need for a multi-directional surround sensing device and system that is particularly effective and suitable for use in mobile vehicles, and aspects of the present invention seek to address at least one or more of the issues noted above.

[0008] Statements of Invention

[0009] In accordance with a first aspect of the invention, there is provided an obstacle sensing system in or on a host carrier, the obstacle sensing system comprising at least two sensor devices, each sensor device comprising a base unit having in or on a planar outer surface thereof first, second and third transducer arrays, each transducer array comprising a plurality of active transducer elements, one or more of which are transmitters and another or more of which are receivers, the first second and third transducer arrays being arranged along said planar outer surface of said base, in side by side and spaced apart relation, such that said second transducer array is substantially central and the first and third transducer arrays are located on either side of said second transducer element, the sensor device further comprising a first reflector plate mounted in relation to said first transducer array at substantially 135° relative to said planar outer surface of the base unit, and a second reflector plate mounted in relation to said third transducer array at substantially 45° to said planar outer surface of the base, such that, in use, waveform beams emitted by the first, second and third transducer arrays cover a 270° region around said sensor device, the obstacle sensing system further comprising an analysis module for receiving and analysing reflected signals received by transducer elements of one or more of said transducer arrays to generate target data and identify thereby obstacles in the vicinity thereof, said at least two sensor devices being arranged and configured in or on said host carrier such that the beams formed by the transducer elements of the transducer arrays thereof at least partially overlap to provide at least bifocal / bistatic sensor coverage around a peripheral region of said host carrier. In an obstacle sensing system substantially as described above, in which the host carrier is a vehicle, and the system may beneficially comprise a plurality of said sensor devices mounted at or near respective comers of a vehicle such that the beams formed by the transducer elements of the transducer arrays of adjacent sensors overlap to provide at least bifocal / bistatic sensor coverage all around a peripheral region of said vehicle.

[0010] In a preferred embodiment, the sensor devices may be arranged and configured such that the beams formed by the transducer arrays of adjacent sensor devices overlap to provide trifocal / tristatic sensor coverage at a region adjacent said one or more comers of said vehicle.

[0011] The central transducer array of each sensor device may, beneficially, be configured such that signals transmitted and / or received by the transducer elements thereof are unhindered, in normal use.

[0012] Beneficially, the signals received and / or transmitted by said transducer elements of the sensor devices may be radio frequency signals.

[0013] In an embodiment, a distance ‘d’ between the axis of signals emanating from the central transducer array of each sensor device and the centre of the respective reflector plates and a distance ‘h’ between the first and third transducer arrays of each sensor device and the centre of the respective reflector plates may be substantially equal.

[0014] Each sensor device may, beneficially, be enclosed in a housing that is substantially transparent to radio frequency signals.

[0015] In an embodiment, each said sensor device may have, integrated therein, a GNSS (Global Navigation Satellite System) sensor for generating global position data in respect of said host carrier, and the system may further comprise a receiving module configured to extract and combine global position data from each of said at least two sensor devices.

[0016] The system may further comprise a position analysis module for receiving data representative of the combined global position data from said receiving module and combined target data from each of said at least two sensor devices to generate local and central position data with respect to said host carrier.

[0017] According to another aspect of the invention, there is provided a method of sensing an obstacle relative to a host carrier using an obstacle sensing system substantially as described above, the method comprising transmitting beams from active transducer elements of each sensor device and receiving reflected signals at active transducer elements of each sensor device, using said reflected signals to generate respective target data indicative of one or more real or ghost obstacles in the vicinity of said host carrier, combining the target data of at least two of said sensor devices and comparing said combined target data of said at least two sensor devices to identify real obstacles in, and eliminate ghost obstacles from, said target data.

[0018] The method may, beneficially, comprise synchronising the target data of at least two of said sensor devices and comparing said synchronised target data of said at least two sensor devices to identify real obstacles in, and eliminate ghost obstacles from, said target data.

[0019] The method may further comprise using said target data to generate local position data indicative of a location of one or more obstacles relative to said host carrier, obtaining global position data in respect of said host carrier, and fusing said local position data and said global position data to determine actual position data indicative a location of said one or more obstacles relative to said host carrier.

[0020] These and other aspects of the invention will become apparent from the following detailed description.

[0021] Brief Description of the Drawings

[0022] Embodiments of the invention will now be described, by way of examples only, and with reference to the accompanying drawings, in which:

[0023] Figure 1 is a schematic diagram illustrating a sensor for use in a sensing system according to an exemplary embodiment of the present invention; Figure 2 is a schematic diagram illustrating the beam forming operation of the sensor of Figure 1 , in use;

[0024] Figure 3 is a schematic diagram illustrating the sensor of Figure 1 , including the parameters ‘h’ and ‘d’ referenced in the detailed description;

[0025] Figure 4 is a schematic diagram illustrating the sensor of Figure 1 including a housing;

[0026] Figure 5 is a schematic perspective view of a sensor for use in a sensing system according to an exemplary embodiment of the present invention;

[0027] Figure 6 is a schematic perspective view of the sensor of Figure 5 illustrating the beam forming operation thereof, in use;

[0028] Figure 7 is schematic perspective view of vehicle incorporating a quad sensing system according to an exemplary embodiment of the present invention in an internal or external portion thereof, incorporating four sensors of the type illustrated in Figure 1 , for example;

[0029] Figure 8 is a schematic perspective view of a vehicle incorporating a quad sensing system according to another exemplary embodiment of the present invention in an internal or external portion thereof;

[0030] Figure 9 is a schematic plan view of a vehicle incorporating a quad sensing system according to an exemplary embodiment of the invention, illustrating the overlapping operation of the multiple sensors;

[0031] Figure 10 is a schematic plan view of a vehicle incorporating a quad sensing system according to an exemplary embodiment of the invention, illustrating the overlapping operation of the multiple sensors;

[0032] Figure 11 is a schematic plan view of a vehicle incorporating a quad sensing system according to an exemplary embodiment of the invention in an internal or external portion thereof, illustrating the overlapping operation of the multiple sensors;

[0033] Figure 12 is a schematic plan view of a vehicle incorporating a sensing system combining an exemplary embodiment of the invention with cameras; Figure 13 is a schematic diagram illustrating how ghost targets can be eliminated in a sensing system according to an exemplary embodiment of the invention;

[0034] Figure 14 is a schematic diagram illustrating the user view of the ghost target elimination described with reference to Figure 13;

[0035] Figure 15 is a schematic diagram of a combined system, including an ADAS / ADS sensing system, together with a satellite communications system and terrestrial communications unit;

[0036] Figure 16 is a schematic diagram illustrating the general configuration of a combined sensing system of the type described with reference to Figure 15;

[0037] Figure 17 is a schematic diagram illustrating how using the quad-architecture for terrestrial and satellite communications provides the benefits of enhanced coverage, redundancy, enhanced accuracy, and signal security (resilience to interference, jamming, spoofing, etc.); and

[0038] Figure 18 is a schematic diagram illustrating the improved accuracy of a quad sensing system according to an exemplary embodiment of the invention.

[0039] Detailed Description

[0040] In the following description of various exemplary embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which are shown, by way of examples and illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that variations and modifications may be made, without departing from the scope of the invention as defined in the appended claims. The following detailed description is therefore not to be taken in a limited sense.

[0041] The specification may refer to “an”, “one” or “some” embodiment(s) in some parts. This does not necessarily imply that each such reference is to the same embodiment(s), or that the feature applies to only one embodiment. Single features of different embodiments may also be combined to make another embodiment. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms “includes”, “comprises”, “including” and / or “comprising”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, operations, steps, elements, components and / or groups thereof As used herein, the term “and / or” includes any and all combinations and arrangements of one or more of the associated listed items.

[0042] Directional descriptors such as upper, lower, left, right, clockwise, anti-clockwise, front, rear and other similar adjectives are used for clarity and refer to the orientation of the invention as illustrated in the drawings, however it will be clear to those skilled in the art that the invention may not always be oriented as illustrated and the invention is not intended to be limited in this regard.

[0043] In the following detailed description, an exemplary embodiment of a unique, high- precision, fully redundant and signal secure sensing system will be described, that is particularly suited for localization and communication in mobile vehicles.

[0044] 360° coverage around a vehicle is considered necessary for various communication and ADAS / ADS functions. Currently available sensors have a limited field of view and are, therefore, unable to augment each other. In the following description, there is disclosed a wide field-of-view, solid state sensor without any moving parts (thus enabling reduced cost and elimination of the tortional effect in spinning antennas / optics). In the following, therefore, there is disclosed a unique multidirectional sensor / transducer, and a novel multi sensor arrangement / system in which the sensors can be used on a vehicle to provide significant performance benefits in comparison with the current state of the art.

[0045] Referring to Figure 1 of the drawings, there is illustrated schematically an exemplary embodiment of a multi-directional sensing system. The sensing system comprises first, second and third transducer arrays 10, 12, 14 arranged in side-by-side, spaced apart relation. Each transducer array 10, 12, 14 comprises a plurality of individual (active) antenna elements. Whilst not absolutely essential for all embodiments of the invention, it is considered advantageous for the antenna elements to be low profile or planar antenna elements, which are particularly suited to microwave frequency applications (>100MHz). A patch antenna is an antenna formed by etching a patch of conductive material on a dielectric substrate. The dielectric substrate is mounted on a ground plane which supports the structure. Thus, the entire base 16 of the sensor may comprise a ground plane that supports a dielectric substrate on which is provided the arrays 10, 12, 14 of antenna elements. The ground plane, dielectric substrate and antenna elements may be formed using a microstrip technique by fabricating on a printed circuit board (PCB), as will be well known to a person skilled in the art.

[0046] Referring back to Figure 1 of the drawings, the sensor further comprises first and second reflector plates 18, 20. The first reflector plate 18 is mounted relative to the first transducer array 10, at an angle of substantially 135° relative to the plane of the base 16, such that signals 22 emanating horizontally (i.e. orthogonally to the plane of the base 16) from the antenna elements of the first transducer array 10 hit the first reflector plate 18 and are reflected thereby in a direction away from the reflector plate 18 (and away from the center of the sensor) and substantially parallel to the plane of the base 16 (the respective reflected signal is denoted in Figure 1 as 22’).

[0047] The second reflector plate 20 is mounted relative to the third transducer array 14, at an angle of substantially 45° relative to the plane of the base 16, such that signals 24 emanating horizontally (i.e. orthogonally to the plane of the base 16) from the antenna elements of the third transducer array 14 hit the second reflector plate 20 and are reflected thereby in a direction away from the reflector plate 20 (and away from the center of the sensor) and substantially parallel to the plane of the base 16 (the respective reflected signal is denoted in Figure 1 as 24’).

[0048] It will be understood that the above is a simplified description of the operation of the sensor in relation to the reflector plates 18, 20, simply to illustrate their position and function. Thus, three clusters of transducer array elements (which could be printed antennas, slot antennas, optical transducers, etc.) are arranged on a planar PCB and produce energy beams in the ‘upward’ direction. The middle beam 26 (emanating from the second transducer array 12 travels upwards unhindered, whereas the two side beams 22, 24 (emanating from the first and third transducer arrays 10, 14) are reflected at substantially 90° angles by the two reflector plates 18, 20 placed at 45° angles relative to the planar PCB (i.e. the plane on which the transducer arrays are provided). This configuration creates compound beams to cover sectors of 90° each in order to cover a total of 270° of space.

[0049] Referring to Figure 2 of the drawing, and as referenced above, the general formation of the beams 28, 30, 32 formed by the respective transducer arrays 10, 12, 14 is illustrated schematically and, as such, is illustrative in representing the required separation between the central transducer array 12 and the distance between the side transducer arrays 10, 14 and their respective reflectors plates 18, 20.

[0050] Referring now additionally to Figure 3 of the drawings, it will be understood that the three sections of the sensor system comprising, respectively, the three transducer arrays 10, 12, 14, operate independently of each other, except at the 45° interface (between the reflector plates 18, 20 and the respective signals 22, 24). In Figure 3 of the drawings, the parameters ‘d’ and ‘h’ are indicated. Parameter ‘d’ defines the distance between the axis of the signal 26 emanating from the central transducer array 12 and the center of each reflector plate 18, 20. Parameter ‘h’ denotes the distance between the peripheral transducer arrays 10, 14 and the center of the respective reflector plate 18, 20. Independent ‘targets’ located in each region (defined, respectively by the three transducer arrays 10, 12, 14) can be detected independently / separately from each other with the target parameters (range, angle, etc.) being reported correctly (to a control system not shown in Figure 3) regardless of the parameters ‘h’ and ‘d’ referenced above , as long as the transducers (i.e. transmitters) in the three sections have the same time base. This is because the phase center of each section of the system is different from each other (as illustrated schematically in Figure 2 of the drawings) and lies at the center of the transducer array for each section. It is only when a ‘target’ lies at the interface or boundary between two sections that the ‘target’s’ return signal reaches both the central section and one of the peripheral or side sections. In order to optimize this case, the parameter ‘h’ should, beneficially, be chosen to be equal to the parameter ‘d’ to match the path lengths to the ‘target’ so that the return signal from the same ‘target’ is displayed on adjacent cells on the display (of the control system). In an embodiment, this could be optimized by designing the system such that the tangent plane of the reflector plates 18, 20 passes through the origin of the system, i.e. the center of the middle transducer array 12. Nevertheless, the target ranges are usually much higher than the dimensions of the sensor system and, therefore, it would normally be expected that the return signal would be in adjacent cells even when the parameters ‘h’ and ‘d’ are not the same. As a result, the system is highly robust against mechanical tolerances, for example, during system assembly.

[0051] Referring to Figures 4 and 5 of the drawings, the sensing system described above with reference to Figures 1 to 3 can be enclosed in a housing 34 of any suitable shape and size (depending on the required application) to protect the transducer arrays 10, 12, 14 and reflector plates 18, 20 from environmental factors. Indeed, referring to Figure 5 of the drawings, an example sensing system enclosed within a housing 34 could also be provided with a plurality (in this case, four) extended tabs 36 incorporating mounting holes 38 to allow the device to be mounted on the part of a vehicle at which it is required to be utilized.

[0052] Referring to Figure 6 of the drawings, it is illustrated schematically how the beams 28, 30, 32 emanate from the housing 34 when the device is in use, to cover 270° of the space around it.

[0053] Referring to Figure 7 of the drawings, it is envisaged that, in an obstacle sensing system in a vehicle, one or more sensing systems or sensor devices (denoted in the drawing by the housing 34) be installed behind the bumper of any vehicle, one on each of the four comers, for example. In the configuration illustrated in Figure 7 of the drawings, the four sensor devices are installed on the vehicle 40 at the same height from the ground. However, as shown in Figure 8 of the drawings, the sensor devices (denoted in the drawing by the housing 34) could be installed on a vehicle 40 at different heights from the ground. This configuration could provide better target differentiation (or resolution) in the vertical plane by utilizing the phase difference between two sensor devices “looking” at the same ‘target’. Referring to Figure 9 of the drawings, it can be readily seen how the 270° waves emerge from each sensor device 34 to provide coverage all the way around the vehicle 40.

[0054] As shown in the above-referenced figures, the waves from each of the four corner sensing systems overlap with those of adjacent sensing systems, which provides:

[0055] 1 . Full 360° coverage around the vehicle to create a virtual “safety bubble” around the vehicle. In fact, with four sensing systems, each having 270° coverage, the total coverage is 4 x 270° = 1080° coverage, which is equivalent to 360° three times over.

[0056] Referring to Figure 10 of the drawings, we can partition the space around the vehicle 40 into eight sections:

[0057] • The front, back and two side regions of the vehicle 40 are covered by two respective sensing systems, providing high-accuracy bifocal vision / bistatic coverage;

[0058] • The four corner regions are covered by three sensing systems on the vehicle simultaneously, providing another degree of freedom for even higher precision sensing.

[0059] 2. Higher precision localization of targets: The targets can be sensed from different perspectives; hence the accuracy of localizing targets increases beyond what is possible with a single sensor.

[0060] • This includes higher precision in range and azimuth when all sensors are installed on a vehicle at the same height.

[0061] • In the case of sensors installed on a vehicle at different heights, this includes higher precision in range, azimuth, and elevation.

[0062] 3. Better cross-range imaging: The new sensing architecture provides a new system for cross-range resolution enhancement through synthetic aperture radar (SAR) techniques. The corner regions with tri-focal coverage could provide extremely high-resolution imaging of the environment around the vehicle. Redundancy: If one sensor stops working due to a failure, the remaining three sensors provide a backup for the failed sensor and the full 360-degree coverage remains intact. Signal security due to spatial diversity: The system provides resilience to interference, jamming, spoofing, and related security threats. Electronic attacks are directional in nature. If the attack is incident on a conventional sensor, it will blind it or corrupt its data, which cannot be remedied. On the other hand, in the example novel sensor architecture, if one sensor is blinded by interference or jamming, or is showing data corruption due to spoofing, the other three sensors can report targets without any problem. This is the first example of a system providing security through spatially diverse sensor arrangement in a vehicle, as illustrated schematically in Figure 11 of the drawings. In the novel example sensor architecture, if one sensor is blinded by interference or jamming, or is showing data corruption due to spoofing, the other three sensors can report targets without any problem. This is the first example of a system providing high security by means of a spatially diverse sensor arrangement in a vehicle, and this is highlighted in Figure 11.

[0063] Using multiple ADAS sensors on a vehicle with overlapping field-of-view allows the opportunity to: a) detect that an attack is occurring because the attack vectors impact the spatially diverse sensors in varying degrees, b) locate the direction of the attack precisely for mitigation measures, and c) built-in resilience to such attacks because the 360° ‘picture’ around the vehicle is being constructed by four spatially diverse sensors. This leads to an overall resilient on-vehicle ADAS sensor network. This can provide an enormous amount of cyber / network resilience in V2X communications protocols, encryption techniques and the I nternet-of- Vehicles (loV) through the introduction of novel secure communications protocols, encryption techniques and Intrusion Detection Systems (IDS). Hence, this scheme can provide the required step-change to meet the security challenges in modem vehicles. Note that each sensor acts as a primary sensor and a back-up sensor simultaneously, which is considered to be an entirely novel concept. 6. Resolution: The vehicle can combine the view from two or three sensors to come up with a more accurate picture of the environment. Applications include:

[0064] • High Resolution reversing sensor:

[0065] • The resolution of one ADAS / AD sensor is limited by the bandwidth of the system. Current automotive radar bandwidth is limited to a maximum of 4 GHz which gives a best-case / theoretical resolution of 3.75 cm.

[0066] • By combining the data from two corner sensors, it is possible to provide better accuracy than a single sensor. In the above example, sub-centimeter accuracy is possible with two sensors.

[0067] • Elevation measurement at two levels (within one sensor and combine two sensors using techniques like DPCA, mono-pulse, etc.)

[0068] • Fast measurement of target dynamics for motion prediction. Target vehicle maneuvers can be predicted due to different look angles of the sensors combined with the vehicle speed data.

[0069] 7. Augmentation: All four sensors act as the primary sensor and backup sensor at the same time.

[0070] • In theory, only two 270° corner sensors can cover the full 360° around the vehicle.

[0071] • Using four sensors provides much more than a backup - if one sensor develops a fault or is blinded by interference the other sensors can be used to reconstruct the full 360° / 4D image around a vehicle.

[0072] • Targets having high SNR can be detected locally by one sensor, while weak or ambiguous targets can be detected by combining multi-sensor data to enable safe ADAS (advanced driver-assistance systems) and ADS (automated driving systems).

[0073] 8. Immunity to Noise and Weather Phenomena: The overlapping nature of the sensors provides measurements from different aspects which improves the noise immunity and weather rejection of the system. External noises like multipath, clutter, interference, etc. affect different sensors to a varying degree making the system immune as a whole. The same goes for weather phenomena - the clutter from rain, snow, fog, etc. affects different sensors from different aspect angles, making the overall system resilient.

[0074] 9. Multi-Modal / Multi-Frequency: The transducer array elements can be made from multiple technologies, including cameras, LiDAR, radar, thermal, ultrasonic, etc. To process the data from the “multi-sensor”, new computing architectures for data fusion can be devised to simplify the design of vehicles having two different sensing modalities connected using the same power and communications cabling. The sensors can be installed inside the vehicle bumpers and / or or inside / on the roof of the vehicle.

[0075] 10. All ADAS functions enabled using four sensors only, which is a boon for the automotive world.

[0076] • OEMs will save the cost of using a large number of sensors: hence there will be fewer sensors to install and maintain.

[0077] • The power and communications wiring of the sensors inside the vehicle will simplify significantly, saving cost.

[0078] • Fewer sensors means less changes to the vehicle chassis to support the installation of the sensors, hence saving engineering costs;

[0079] • Arguably one of the most important advantages is that the novel architecture allows different ADAS functions to be turned on / off through software-supported / software-defined vehicle architecture.

[0080] 11 . Sensing Layer for Autonomous Driving: New sensor installation architectures can be envisaged based on the disclosed technology. An example sensor installation is illustrated in Figure 12 of the drawings, which includes 270-degree cameras installed in the four comers of the roof and 270-degree radars or lidars installed in the four comers of the car inside the bumpers.

[0081] ■The sensors can be used all together, in pairs, or in any combination desired. •Due to the symmetric arrangement, the data from all sensors can be processed and / or fused by a single central data processor.

[0082] Multipath Ghost Rejection using the Quad-Sensor System (described above)

[0083] In the sensor architecture described above, four sensing systems are utilized, one on (or near) each corner of a vehicle. Hereinafter, this architecture may be referred to as a quad sensor architecture. The quad sensor architecture enables a new method of eliminating ghost targets arising due to inter-target multipath. This phenomenon happens when two or more targets are close by. In dense target environments, the multipath vectors can add up to create a large number of ‘ghost targets’, which can cause confusion and suboptimal decision making in ADAS / ADS systems. By combining the target detection responses from two or more sensors on a vehicle, the ghost targets can be eliminated, improving the accuracy and reliability of target localization.

[0084] Using vector diagrams, Figure 13 of the drawings illustrates schematically the multipath vectors for the case when the signals bounce first off Target 1 , then off Target 2, and then back to either the left 270° sensor or the right 270° sensor. This is an unwanted return in echolocating sensor and can lead to the impression that there is a ghost target behind an actual target. In Figure 13 of the drawings, four cases leading to four ghost targets are illustrated.

[0085] In Figure 14, there are shown schematically the left and right sensor screens that may be provided in a ADAS or ADS system, and they illustrate, in this case, the images as they may be shown to a user (in relation to the specific situation illustrated and described in relation to Figure 13 of the drawings).

[0086] As shown, ghosts 3 and 4 have been eliminated by combining the waveforms of the left and right sensors. Ghosts 1 and 2 are detected at different locations by both sensors while the actual targets are detected at their correct positions. Hence the multipath ghosts can be identified and eliminated by combining the data from both sensors using a suitable algorithm. Beneficially, the waveforms of the left and right sensors are combined through synchronization to give the best outcome in terms of resolution, image quality, etc. However, the waveforms could be combined asynchronously and still provide adequate ghost detection, resolution and image quality, at least for some applications.

[0087] Quad -Sensor System for Locating Sensing and Communications

[0088] The quad-sensor configuration described above is not limited to ADAS / ADS sensing. Indeed, terrestrial and satellite communications can also be enhanced using the approach described above. Referring to Figure 15 of the drawings, there is illustrated schematically a system block diagram including ADAS / ADS transducer systems with terrestrial (cellular, V2X, etc.) and satellite communications electronics in the same package.

[0089] Referring to Figure 16 of the drawings, an example is illustrated comprising an arrangement of the antennas for location sensing and communications. Other arrangements are, of course, possible. The ADAS / ADS sensor system has the transducer arrays with 45° reflectors, as discussed previously. The sat-comms 50 and land-comms 60 antennas and circuits could be placed either side of the ADAS / ADS transducer arrays. This system combines various ADAS / ADS and Communications functions in one unit, and the quad-sensor architecture provides redundancy and futureproofing for the software-defined vehicles (SDV) era. In Figure 16, there is illustrated schematically how the antenna / transducer systems of the elements can appear together in a single unit. The illustrated system shows how the sensing and communication capabilities can be contained in a single unit, and can be installed in the same way as in relation to the vehicular sensing described above (for the ADAS / ADS case only).

[0090] Referring to Figure 17 of the drawings, there is illustrated schematically how using the quad-architecture for terrestrial and satellite communications provides the previously- discussed benefits of enhanced coverage, redundancy, enhanced accuracy, and signal security (resilience to interference, jamming, spoofing, etc.).

[0091] As shown in Figure 17, the waves from the corner sensors overlap with the respective adjacent sensor, which provides: Full 360° coverage around the vehicle ensures connectivity for all directions. The four channels can be used to enhance the connectivity data or communicate with different entities at the same time to avoid data overload. If one receiver fails for any reason, there are three more receivers to provide redundancy. Four GNSS receivers enhance the signal to noise ratio and the accuracy of providing global positioning data by extracting global position data using, for example, a real-time kinematics (RTK) algorithm, and combining the signals from four receivers. This combined global position data can then be combined with local position data derived using the sensors to provide real-time, accurate local and central position data with respect to the vehicle. The four receivers can be used to extract inertial navigation data (roll, pitch, yaw) which can be used to record and validate the trajectory of the vehicle. In addition, this data can be shared with other vehicles (through cellular or dedicated V2X, etc.) for them to predict the motion of the vehicle more accurately, which leads to an overall safe driving experience for all road users. The local positioning data (from the ADAS / ADS unit) and the global positioning data can be combined to locate objects around the vehicle precisely in the “world” coordinate system.

[0092] • Specifically, if a vehicle knows its own global position less accurately, it will measure the location of targets and road infrastructure with less accuracy. This can lead to false positives in the ADAS / ADS unit. The inaccurate data will not be reliable enough to be shared with other road users for decision making.

[0093] • An example illustrated in Figure 18 of the drawings is that of a lorry parked on the roadside at a bend in the road, which can appear as a hazard to the ADAS sensor due to its line-of-sight operation. However, if the vehicle knows its own global position accurately and maps the ADAS / ADS data on a navigation map, then the parked lorry will be classed as safe. • Hence, fusing accurate local positioning data with accurate global positioning data is an optional, but highly beneficial, step for sensor-map fusion and providing trusted data to other vehicles and the relevant infrastructure.

[0094] • Beneficially, a GNSS receiver may be incorporated within each sensor device 34, thus providing the local and global position sensors in a single package, using the same architecture and circuitry, thereby minimizing the hardware required to provide both local and central position data in respect of the vehicle.

[0095] 6. Receiving communication data from four receivers can mitigate the effects multipath signal propagation in way similar to the ADAS / ADS sensors described previously.

[0096] 7. It can be noted that the disclosed topology does not depend on the specific type of satellite communications or terrestrial communications employed.

[0097] 8. The system is quite suitable for software-defined vehicles, in which different ADAS, ADS and comms functions can be turned on / off depending on the OEM’s offerings.

[0098] It will be apparent to a person skilled in the art, from the foregoing description, that modifications and variations can be made to the described embodiments without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS1 . An obstacle sensing system in or on a host carrier, the obstacle sensing system comprising at least two sensor devices, each sensor device comprising a base unit having in or on a planar outer surface thereof first, second and third transducer arrays, each transducer array comprising a plurality of active transducer elements, one or more of which are transmitters and another or more of which are receivers, the first second and third transducer arrays being arranged along said planar outer surface of said base, in side by side and spaced apart relation, such that said second transducer array is substantially central and the first and third transducer arrays are located on either side of said second transducer element, the sensor device further comprising a first reflector plate mounted in relation to said first transducer array at substantially 135° relative to said planar outer surface of the base unit, and a second reflector plate mounted in relation to said third transducer array at substantially 45° to said planar outer surface of the base, such that, in use, waveform beams emitted by the first, second and third transducer arrays cover a 270° region around said sensor device, the obstacle sensing system further comprising an analysis module for receiving and analysing reflected signals received by transducer elements of one or more of said transducer arrays to generate target data and identify thereby obstacles in the vicinity thereof, said at least two sensor devices being arranged and configured in or on said host carrier such that the beams formed by the transducer elements of the transducer arrays thereof at least partially overlap to provide at least bifocal / bistatic sensor coverage around a peripheral region of said host carrier.

2. An obstacle sensing system according to claim 1 , wherein said host carrier is a vehicle, and the obstacle sensing system comprises a plurality of said sensor devices mounted at or near the comers of a vehicle such that the beams formed by the transducer elements of the transducer arrays of adjacent sensors overlap to provide at least bifocal / bistatic sensor coverage all around a peripheral region of said vehicle.

3. An obstacle sensing system according to claim 2, wherein said sensor devices are arranged and configured such that the beams formed by the transducer arrays of adjacent sensor devices overlap to provide trifocal / tristatic sensor coverage at a region adjacent said one or more comers of said vehicle.

4. An obstacle sensing system according to any of the preceding claims, wherein said central transducer array of each sensor device is configured such that signals transmitted and / or received by the transducer elements thereof are unhindered, in normal use.

5. An obstacle sensing system according to any of the preceding claims, wherein signals received and / or transmitted by said transducer elements of the sensor devices are radio frequency signals.

6. An obstacle sensing system according to any of the preceding claims, wherein a distance ‘d’ between the axis of signals emanating from the central transducer array of each sensor device and the centre of the respective reflector plates and a distance ‘h’ between the first and third transducer arrays of each sensor device and the centre of the respective reflector plates are substantially equal.

7. An obstacle sensing system according to any of the preceding claims, wherein each sensor device is enclosed in a housing that is substantially transparent to radio frequency signals.

8. An obstacle sensing system according to any of the preceding claims, wherein each said sensor device has, integrated therein, a GNSS sensor for generating global position data in respect of said host carrier, and wherein the system further comprises a receiving module configured to extract and combine global position data from each of said at least two sensor devices.

9. An obstacle sensing system according to claim 8, further comprising a position analysis module for receiving data representative of the combined global position data from said receiving module and combined target data from each of said at least two sensor devices to generate local and central position data with respect to said host carrier.

10. A method of sensing an obstacle relative to a host carrier using an obstacle sensing system according to any of the preceding claims, the method comprisingtransmitting beams from active transducer elements of each sensor device and receiving reflected signals at active transducer elements of each sensor device, using said reflected signals to generate respective target data indicative of one or more real or ghost obstacles in the vicinity of said host carrier, combining the target data of at least two of said sensor devices and comparing said combined target data of said at least two sensor devices to identify real obstacles in, and eliminate ghost obstacles from, said target data.11 .A method according to claim 10, comprising synchronising the target data of at least two of said sensor devices and comparing said synchronised target data of said at least two sensor devices to identify real obstacles in, and eliminate ghost obstacles from, said target data.

12. A method according to claim 10 or claim 11 , further comprising using said target data to generate local position data indicative of a location of one or more obstacles relative to said host carrier, obtaining global position data in respect of said host carrier, and fusing said local position data and said global position data to determine actual position data indicative a location of said one or more obstacles relative to said host carrier.

Images