GB2609202A

GB2609202A - Housing assembly for a sensor assembly, sensor assemblies, vehicles with sensors, and methods of improving sensors

Info

Publication number: GB2609202A
Application number: GB2110509.3A
Authority: GB
Inventors: Keene David; Brewerton Simon
Original assignee: Richmond Design and Marketing Ltd
Current assignee: Richmond Design and Marketing Ltd
Priority date: 2021-07-21
Filing date: 2021-07-21
Publication date: 2023-02-01
Also published as: GB202110509D0

Abstract

The present invention relates to a housing assembly 1 for a sensor assembly. The housing assembly comprises a housing 11, a motor 17, and a controller 18. The housing 1 comprises an outer wall 111 defining an internal volume 112 for receiving a sensor responsive to electro-magnetic radiation, and an aperture 113 arranged in the outer wall 111 to allow light to pass into the internal volume 112. The motor 17 is configured to rotate the housing 11. The controller 18 is configured to control the motor 17 to control rotation of the housing 11 to align the aperture 113 with a field of view of the sensor. Controlling rotation of the housing 11 allows light from a plurality of directions to pass into the internal volume 112 of the housing 11 via the aperture 113 and inhibits the ingress of material into the internal volume 112 through the aperture 113. The housing assembly 1 may be particularly suitable for use with a rotating lidar sensor. Also disclosed is a sensor assembly, methods of obtaining image data using a sensor assembly, a self-propelled airside dolly comprising a sensor assembly, a method of retrofitting a self-propelled airside dolly, and a method of improving the performance of a sensor responsive to electro-magnetic radiation.

Description

HOUSING ASSEMBLY FOR A SENSOR ASSEMBLY, SENSOR ASSEMBLIES, VEHICLES WITH SENSORS, AND METHODS OF IMPROVING SENSORS

TECHNICAL FIELD

The present invention relates to a housing assembly for a sensor assembly. The invention also relates to a sensor assembly, methods of obtaining image data using a sensor assembly, a self-propelled airside dolly comprising a sensor assembly, a method of retrofitting a self-propelled airside dolly, and a method of improving the performance of a sensor responsive to electro-magnetic radiation.

BACKGROUND

Sensors responsive to electro-magnetic radiation, such as lidar sensors or scanners, are known to be vulnerable to environmental factors, such as rain, snow, high levels of sunlight, and malicious damage. The sensors are typically expensive and easily damaged. it is therefore desirable to protect the sensors. Prior art solutions involve placing a sensor in a casing or housing. It is required for light to be able to pass through the outer wall of the housing and to the sensor; the housing is therefore typically constructed from a transparent material, such as plastic. Known transparent materials are less robust than some opaque materials, such as metal. Prior art sensor housings are therefore themselves vulnerable to damage, and therefore may not offer much in the way of protection. Furthermore, material such as snow, ice, or debris can settle on the housings, thereby obstructing the passage of light to the sensor.

SUMMARY OF INVENTION

An aspect of the invention provides a housing assembly for a sensor assembly. The housing assembly comprises a housing, a motor, and a controller. The housing comprises an outer wall defining an internal volume for receiving a sensor responsive to electro-magnetic radiation, and an aperture arranged in the outer wall to allow light to pass into the internal volume. The motor is configured to rotate the housing. The controller is configured to control the motor to control rotation of the housing to align

the aperture with a field of view of the sensor.

The above aspect of the invention provides a housing assembly for a sensor responsive to electro-magnetic radiation, such as an optical sensor, which overcomes problems presented by prior art sensor housings. The housing can also be used with other sensors, such as acoustic sensors. The housing assembly is particularly applicable to optical sensors configured to receive light from a plurality of directions. An example of such a sensor is a lidar sensor. A lidar sensor transmits a laser pulse to an object in the sensor's surroundings and receives the reflected pulse after it has been reflected by the object. The sensor measures the time interval between delivering the pulse and receiving the reflected pulse to determine the distance between the sensor and the object. The sensor delivers pulses and receives reflected pulses at multiple angles in the horizontal and vertical planes in order to build up a picture of the sensor's surroundings. This might be achieved by means of a rotating element which varies the angle at which pulses are delivered and received, or by means of an array of light sources and/or receivers arranged at different angles in the horizontal plane. The sensor might be configured to build up a view of its surroundings covering 360 degrees or less. Alternative sensors which use light to obtain image data may use techniques in which a beam of light is steered, such as a known beam forming IS technique.

A prior art solution to protecting such an optical sensor might be to provide a transparent housing around the sensor. However, as outlined above, such housings are typically limited in terms of robustness, due to the inherent properties of transparent materials, and are prone to becoming obscured due to the build-up of debris, precipitation or other material. The aperture arranged in the outer wall of the housing of the above aspect of the invention means that the outer wall can be formed from an opaque material, such as metal, which is more robust than typical transparent materials. Rotating the housing means that the angular position of the aperture relative to an optical sensor which may be received within the internal volume in use is varied, such that the optical sensor receives light from multiple directions.

The controller may be configured to control the motor to rotate the housing continuously over 360 degrees during operation. Rotating the housing in this way inhibits ingress of debris, precipitation or other material into the internal volume of the housing through the aperture; the aperture is essentially moved out of the line of sight path to the sensor so that debris, precipitation or other material carried by the air outside the internal volume of the housing that would otherwise hit the sensor does not have time to pass through the aperture and fall on the sensor. By having a housing with a narrow aperture the sensor is shielded from material impacting on it from the vast majority of directions. Controlling rotation of the housing therefore provides two effects: allowing light from a plurality of directions to pass into the internal volume of the housing via the aperture: and inhibiting the ingress of material into the internal volume of the housing through the aperture.

Although the housing assembly of the above aspect of the invention is particularly beneficial when used with an optical sensor as described above, such as a lidar sensor, the invention is not limited to use with such sensors. For example, an optical sensor which forms part of a camera could be received within the internal volume, and a lens of the camera could be arranged to rotate with the housing such that the lens is always aligned with the aperture of the housing. The housing could then be rotated to align the aperture, and therefore the lens of the camera, with an object to capture an image of the object. The housing would provide robust protection for the camera while allowing the camera to capture images at multiple angles. I5

By " electro-magnetic radiation" we primarily mean human visible spectrum light but also mean other wavelengths such as infra-red, or ultraviolet, and radar, microwave, x-ray, etc -wavelengths primarily for imaging. "Electromagnetic radiation" can be substituted for "light". The first envisaged application of the invention is in relation to a spinning LIDAR sensor and imaging system. RADAR is another possible application.

Another aspect of the invention provides a housing assembly for a sensor assembly, comprising: a housing comprising: an outer wall defining an internal volume for receiving a sensor responsive to electro-magnetic radiation; an aperture arranged in the outer wall to allow light to pass into the internal volume; and a rotation mechanism configured to rotate the housing toto inhibit ingress of debris, precipitation or other material into the internal volume of the housing through the aperture.

The rotation mechanism may comprise any suitable means to rotate the housing relative to the sensor mount. Such means may include a motor and an associated controller. Alternatively, or additionally, the rotation mechanism may comprise one or more vanes rotationally fixed relative to the housing, such that the housing is configured to rotate under the power of the wind. It will be appreciated that in some applications, any rotation of the housing may be beneficial. As described above, rotating the hosing essentially moves the aperture out of the path of debris, precipitation or other material carried by the air outside the internal volume of the housing. In some applications, it may be advantageous to reduce the energy consumption of the housing assembly. The one or more vanes may be beneficial here.

The following statements are applicable to either of the above aspects of the invention: The housing assembly may comprise a sensor mount, for a sensor responsive to electro-magnetic radiation, arranged within the internal volume. The housing may be rotatable relative to the sensor mount. The motor may be configured to rotate the housing relative to the sensor mount.

The housing assembly may comprise any suitable means for allowing the housing to rotate relative to the sensor mount. For example, the sensor mount may be mounted to an intern& wall of the housing via a gimbal to allow the housing to rotate independently of the sensor mount. Alternatively, the sensor mount may be fixed to an inner race of a bearing and an outer race of the bearing may be fixed to an internal wall of the housing The housing assembly may comprise means to pressurise air within the internal volume of the housing. Such means may comprise a pump, a fan, an impeller or the like. This advantageously allows the aperture to be left unobscured as the pressurised air within the internal volume will prevent material in the air outside the housing from passing through the aperture in the outer wall of the housing.

The aperture may comprise a first opening configured to allow air to pass out of the internal volume. The housing may further comprise a second opening configured to allow air to pass into the internal volume to allow a positive pressure gradient between the first opening and the second opening when the housing is rotated by the motor. This may cause air to be pumped into the internal volume through the second opening and out of the internal volume through the first opening.

The positive pressure gradient means that the air pressure within the internal volume of the housing is greater than the air pressure outside the housing in the vicinity of the aperture. As such, precipitation, such as rain, snow or hail, and debris travelling through the air outside the housing is inhibited from collecting at the aperture and obscuring it, and from entering the housing through the aperture. in use, this protects a sensor which may be received within the internal volume and improves its view of the world through the aperture when it is snowing, raining, or icy. The pressure differential between the internal volume of the housing and outside the housing that inhibits the build-up of material around the aperture, thereby inhibiting restricting of the passage of light through the aperture into the internal volume of the housing, is produced in many embodiments by rotating the housing, for example by continuously spinning the housing.

The housing may be configured such that when the housing assembly is installed in use, the underside of the housing provides the second opening. In other words, the second opening faces the ground in use This may help inhibit the ingress of precipitation, or other material falling towards the housing assembly, into the internal volume of the housing through the second opening. Providing the second opening at the underside of the housing may help to ensure that 'cleaner air is drawn into the internal volume of the housing for the purpose of creating the positive pressure gradient between the first opening and the second opening. That is to say, air that is carrying less material (such as rain or snow or dust) with it.

The outer wall may extend over the top of the housing to prevent precipitation or other material from falling into the internal volume of the housing. in some examples, the housing could take the form of a tube which is rotatable about a longitudinal axis of the tube (which longitudinal axis may be disposed generally vertically), with the tube being open at the bottom and closed at the top. It will be appreciated that this is merely illustrative, and the housing can take any suitable geometric form and does not necessarily take the form of a tube.

The housing assembly may comprise a source of pressurised air, such as an impeller, which impeller may be configured to rotate with the housing. The impeller may be arranged between the first opening and the second opening such that the impeller is located within an airflow between the second opening and the first opening in use. The effect of rotation of the housing alone may be sufficient to pressurise the air within the internal volume of the housing, or it may not. An impeller may encourage the flow of air from the second opening into the internal volume of the housing. This may help to increase the pressure differential between the internal volume of the housing and the air outside the housing. Another additional or alternative source of pressurised air may be envisaged, for example a pressurised reservoir of air or a fan or a pump.

The impeller may comprise one or more vanes mounted within the internal volume of the housing or mounted outside the internal volume of the housing proximate the second opening. Alternatively, or additionally, an internal wall of the housing may be I5 shaped, or comprise features or formations, configured to draw air into the internal volume when the housing is rotated.

The housing assembly may comprise a driven pump configured to pressurise the air within the internal volume of the housing. The pump may be selectively operated in use to assist the effect of the rotation of the housing in pressurising the air within the internal volume of the housing.

The housing assembly may comprise an air filter arranged between the first opening and the second opening such that the air filter is located within an airflow between the second opening and the first opening in use This may inhibit the ingress of precipitation or other material into the internal volume of the housing through the second opening.

The housing assembly may comprise a shutter, an actuator, and a controller. The shutter may be configured to move between a closed position, in which the shutter covers the aperture, and an open position, in which the shutter uncovers the aperture. The actuator may be configured to move the shutter between the closed position and the open position. The controller may be configured to control the actuator to sequentially move the shutter between the closed position and the open position.

In some embodiments, possibly the housing assembly need not rotate -it could have a shutter that temporarily opens it and closes it, and may not need rotation if the system were to be intended for a restricted field of view, or if the sensor had some other way of viewing other angles The controller may be the same controller configured to control the motor to control rotation of the housing, or the controller may be a separate controller. The housing assembly may comprise any suitable number of controllers required to carry out the functions of the housing assembly. Each controller may comprise any suitable number and arrangement of processors, memories, and other necessary components.

To sequentially move the shutter between the closed position and the open position means to move the shutter from the closed position to the open position, then from the open position to the closed position, then from the closed position to the open position and so on for a period of time. This action of moving the shutter between the dosed and open positions may cause debris or precipitation, or other material, to be forced away from the vicinity of the aperture, and inhibits ingress of material into the internal volume of the housing through the aperture.

The controller may be configured to control the actuator to cause the shutter to adopt the closed position when the housing assembly is not operational. In use, the housing assembly may not be operational when a sensor received within the internal volume of the housing is not operational. Closing the shutter may help to protect a sensor received within the internal volume of the housing when the sensor is not in use, for example by inhibiting an act of vandalism via the aperture.

The housing assembly may comprise a fan assembly configured to generate an air curtain across the aperture. The air curtain advantageously inhibits ingress of precipitation, debris, or other material through the aperture when the housing assembly is in use.

The fan assembly may comprise any suitable number and arrangement or impellers, motors, and controllers required to generate an air curtain across the aperture.

Another aspect of the invention provides a housing assembly for a sensor assembly. The housing assembly comprises a housing, a shutter, an actuator, and a controller. The housing comprises an outer wall defining an internal volume for receiving a sensor responsive to electro-magnetic radiation, and an aperture arranged in the outer wall to allow light to pass into the internal volume. The shutter is configured to move between a closed position, in which the shutter covers the aperture, and an open position, in which the shutter uncovers the aperture. The actuator is configured to move the shutter between the closed position and the open position. The controller is configured to control the actuator to sequentially move the shutter between the closed position and the open position.

The controller may be configured to control the actuator to cause the shutter to adopt the closed position when the housing assembly is not operational. In usc, the housing assembly may not be operational when a sensor received within the internal volume of the housing is not operational. Closing the shutter may help to protect a sensor received within the internal volume of the housing when the sensor is not in use, for example by inhibiting an act of vandalism via the aperture Another aspect of the invention provides a housing assembly for a sensor assembly.

The housing assembly comprises a housing and a fan assembly. The housing comprises an outer wall defining an internal volume for receiving a sensor responsive to electro-magnetic radiation, and an aperture arranged in the outer wall to allow light to pass into the internal volume. The fan assembly is configured to generate an air curtain across the aperture.

The following statements are applicable to any of the above aspects of theinvention: The aperture may be completely unobstructed, i.e. the aperture may be a hole within the outer wall of the housing where no material is present. The housing assembly may comprise a transparent cover arranged to cover the aperture. The transparent cover may prevent ingress of precipitation, debris or other material into the internal volume of the housing through the aperture, while still allowing light to pass through the aperturc.

The outer wall of the housing may be metal. Because the aperture arranged in the outer wall allows light (em. waves) into the internal volume of the housing, the outer wall of the housing is not required to be formed from a transparent material. The outer wall can therefore be formed from a more robust material, such as metal or a hard, opaque plastic. Embodiments of the invention provide means to inhibit ingress of precipitation, debris or other material into the internal volume of the housing through the aperture; therefore, the aperture can be arranged in the outer wall of the housing without the risk of precipitation, debris or other material from entering the internal volume of the housing, and potentially damaging a sensor which may be received within the internal volume of the housing.

IS As described above, the aperture being arranged in the outer wall of the housing means that the housing can be formed from an opaque material. This provides a further advantage in protecting a sensor which may be received within the internal volume of the housing from over-exposure to sunlight. Some sensors may be sensitive to too much sunlight incident on the sensor at any angle. Too much sunlight may damage the sensor or affect the accuracy of data obtained by the sensor. Too much sunlight can flood out detected signals -causing the sensor to see a maximum signal at all/too many angles of view, blinding the sensor. An opaque outer wall of the housing with a restricted field of view through an aperture, such as a slot, may protect a sensor from sunlight incident on the sensor at angles other than those aligned with the aperture in the outer wall.

The housing assembly may comprise a heater configured to heat the inside of the housing, for example to heat air flowing into the internal volume through the second opening when the housing is rotated or to heat air forming the air curtain in applicable embodiments. A heater may prevent moisture from freezing within the internal volume of the housing and may help to prevent the temperature of a sensor from falling below a lower threshold operating temperature.

The housing assembly may comprise a cooler configured to cool the inside of the housing, for example to cool air flowing into the internal volume through the second opening when the housing is rotated relative to the sensor mount in applicable embodiments. This may help to prevent the temperature of a sensor from rising above an upper threshold operating temperature.

The aperture may comprise a first aperture and the housing may comprise a further aperture arranged in the outer wall to allow light to pass into the internal volume. The further aperture may be angularly spaced apart from the first aperture about the axis of rotation of the housing. in applicable embodiments, the controller may be configured to control the motor to control rotation of the housing to align the further aperture with a field of view of the optical sensor. The further aperture may increase the amount of data captured or improve data captured by a sensor received within the internal volume of the housing.

The further aperture may be spaced apart from the first aperture about the axis of rotation of the housing by 180 degrees.

The housing may comprise more than two apertures arranged in the outer wall of the housing. For example, the housing may comprise three, four, six or eight apertures arranged in the outer wall of the housing. The apertures may be spaced equidistantly about the axis of rotation of the housing, or spaced in any suitable manner.

The housing may comprise a lip projecting from the outer wall away from the internal volume. The housing is preferably configured such that when the housing assembly is installed in use, the lip is located above the aperture. The lip may help to inhibit precipitation or other material from falling into the internal volume of the housing through the aperture, where the aperture is uncovered, or from building up around the aperture.

The housing assembly may comprise an external surface outside the internal volume of the housing. The motor may be configured to rotate the housing relative to the external surface. The external surface may be configured to cover the aperture when the aperture is aligned with the external surface. The controller may be configured to control rotation of the housing to adopt a stationary position at which the aperture is aligned with the external surface. This provides a 'park' position for the housing in which the aperture is obstructed by the external surface. This inhibits the ingress of material into the internal volume of the housing through the aperture. This may be particularly advantageous in helping to prevent vandalism of a sensor mounted to the sensor mount when the housing assembly is not in operation. For example, this may inhibit someone from spraying paint or another substance through the aperture which may cause damage to a sensor received within the internal volume of the housing.

The housing assembly may comprise a mounting structure, such as a pole for mounting the housing assembly in the ground, and the extern& surface may comprise a surface of the mounting structure. The external surface may be any surface of the housing assembly which the housing is configured to rotate relative to and which substantially covers the aperture of the housing when the aperture is aligned with the external surface. For example, the housing assembly may comprise a non-rotating shield to provide the external surface. In some examples, the housing assembly may form part of an autonomous vehicle and the external surface may be provided by a surface of the autonomous vehicle.

While the internal volume of the housing of the above embodiments of the invention is for receiving a sensor responsive to electro-magnetic radiation, it will be appreciated that the internal volume is not limited to receiving a sensor responsive to electro-magnetic radiation. The intern& volume may also be for receiving a sensor responsive to acoustic radiation, such as sound waves. Likewise, the aperture of the housing of the above embodiments of the invention may be arranged to allow acoustic radiation to pass into the internal volume. Therefore, while the invention is primarily applicable to sensors responsive to electro-magnetic radiation, the invention is also applicable to sensors responsive to acoustic radiation.

Another aspect of the invention provides a sensor assembly comprising the housing assembly of any of the above embodiments, and a sensor responsive to electromagnetic radiation received within the internal volume. The controller may be configured to control the motor to control rotation of the housing to align the aperture with a field of view of the sensor received within the internal volume.

In embodiments in which the housing assembly comprises the shutter, the controller configured to control the actuator to move the shutter between the closed position and the open position may be configured to control the actuator to cause the shutter to: adopt the open position when the aperture is aligned with a field of view of the sensor, and adopt the closed position when the aperture is not aligned with a field of view of the sensor. This may help to minimise the amount of time the shutter is open, by closing the shutter when it is not required to pass light through the aperture, thereby minimising ingress of precipitation, debris, or other material through the aperture.

The sensor may be any suitable sensor configured to receive and measure a variable of light. As mentioned earlier, 'light' refers to any visible or non-visible electromagnetic radiation. For example, the sensor may be an infrared or ultra-violet sensor.

In some examples, the sensor may be a sensor of a camera mounted to the sensor mount.

The sensor may be an imaging sensor which in use captures signals that are used to generate an image.

IS

The apparatus may have an emitter adapted to emit signals which are reflected back from the outside environment to pass through the aperture or shuttered aperture to be detected by the sensor. The emitter may be within the housing so that the emitted signal passes through the aperture or shuttered aperture.

The sensor may comprise a lidar sensor. This may include a lidar sensor with a rotating element or a solid-state lidar sensor. The housing assembly of the present invention may be particularly suited to use with a lidar sensor, all though the invention is by no means limited to such a use. A lidar sensor typically captures image data within a narrow field of view. The sensor may capture a plurality of 'vertical slices' of an image (at different angular positions) for a processor to then combine to produce a full image. The narrow field of view of a lidar sensor means that the aperture of the housing can &so be narrow, thereby reducing the likelihood of ingress of precipitation or other material into the internal volume of the housing through the aperture.

The sensor may comprise one or more light source and one or more light receiver. The controller may be configured to control the motor to control rotation of the housing to align the aperture to transmit light from the one or more light source and receive light at the one or more light receiver. In embodiments in which the housing assembly comprises the shutter, the controller configured to control the actuator to move the shutter between the closed position and the open position may be configured to control the actuator to cause the shutter to: adopt the open position when the aperture is aligned to transmit light from the one or more light source and receive light at the one or more light receiver, and adopt the closed position when the aperture is not aligned to transmit light from the one or more light source and receive light at the one or more light receiver.

The one or more light source may be configured to transmit light in a plurality of directions. The one or more light receiver may be configured to receive light from a plurality of directions. The controller may be configured to control the motor to control rotation of the housing to align the aperture to transmit light from the one or more light source in each of the plurality of directions and receive light at the one or more light receiver from each of the plurality of directions. In embodiments in which the housing assembly comprises the shutter, the controller configured to control the actuator to move the shutter between the closed position and the open position may be configured to control the actuator to cause the shutter to: adopt the open position when the aperture is aligned to transmit light from the one or more light source in each of the plurality of directions and receive light at the one or more light receiver from each of the plurality of directions, and adopt the closed position when the aperture is aligned not to transmit light from the one or more light source or receive light at the one or more light receiver.

The sensor may comprise a plurality of light sources and a plurality of light receivers.

Each of the light sources may be configured to transmit light in a different direction and each of the light receivers may be configured to receive light from a different direction. Each of the light sources may have an associated light receiver, wherein the direction of light transmitted by one of the light sources is substantially the same as the direction of light received at the associated light receiver. The light sources and associated light receivers may form an array of light sources and light receivers. In such embodiments, the controller may be configured to control the motor to rotate the housing to align the aperture with each light source and its associated light receiver. In embodiments in which the housing assembly comprises the shutter, the controller configured to control the actuator to move the shutter between the closed position and the open position may be configured to control the actuator to cause the shutter to: adopt the open position when the aperture is aligned with each light source and its associated light receiver, and adopt the closed position when the aperture is not aligned with any of the light sources or their associated receiver.

The sensor may comprise a single light source configured to transmit light in a plurality of different directions and a plurality of light receivers each configured to receive light from a different direction. in such embodiments, the controller may be configured to control the motor to rotate the housing to align the aperture with each of the plurality of light receivers. The controller may be configured to control the motor to rotate the housing at a constant predetermined angular velocity. In embodiments in which the housing assembly comprises the shutter, the controller configured to control the actuator to move the shutter between the dosed position and the open position may be configured to control the actuator to cause the shutter to: adopt the open position when the aperture is aligned with the light receivers, and adopt the closed IS position when the aperture is not aligned with any of the light receivers.

The sensor may comprise a rotating element configured to rotate to change the direction in which light is transmitted from the one or more light source and change the direction from which light is received at the one or more light receiver. The controller may be configured to control rotation of the housing to synchronise rotation of the housing with rotation of the rotating element to align the aperture to transmit light from the one or more light source in each of the plurality of directions and receive light at the one or more light receiver from each of the plurality of directions.

In embodiments in which the housing assembly comprises the shutter, the controller configured to control the actuator to move the shutter between the closed position and the open position may be configured to control the actuator to cause the shutter to: adopt the open position when the aperture is aligned to transmit light from the one or more light source in each of the plurality of directions and receive light at the one or more light receiver from each of the plurality of directions, and adopt the closed position when the aperture is not aligned to transmit light from the one or more light source or receive light at the one or more light receiver.

The rotating element may be configured to rotate continuously over 360 degrees when in use. In such embodiments, the housing may also rotate continuously over 360 degrees when in use.

The sensor may comprise a single light source and a single light receiver. The rotating element may comprise a rotating platform. The single light source and single light receiver may be mounted to the rotating platform. The single light source and single light receiver may be spaced from the axis of rotation of the rotating platform.

The rotating element may comprise a mirror. The mirror may be configured to reflect light from the one or more light source to transmit light from the one or more light source. The mirror may be configured to reflect the reflected light to receive the reflected light at the one or more light receiver.

An advantage of using a mirror is that the one or more light source and/or the one or more light receiver can be arranged in a fixed position relative to the rotating mirror. This makes it easier to provide wired connections to and from the one or more light source and/or one or more light receiver, for example for the purpose of supplying electrical power and/or receiving and/or sending electrical signals.

The rotating element may be configured to rotate about an axis that is parallel or concentric with the axis of rotation of the housing. The rotating element may be configured to rotate about an axis that is not parallel to the axis of rotation of the housing. The axis of rotation of the rotating element may be substantially orthogonal to the axis of rotation of the housing.

In embodiments in which the axis of rotation of the rotating element is substantially orthogonal to the axis of rotation of the housing, the aperture may comprise a first aperture, and the housing may comprise a further aperture arranged in the outer wall and spaced apart from the first aperture about the axis of rotation of the housing by degrees. This may enable the sensor to capture data in a first direction via the first aperture before capturing data in a second direction, opposite the first direction, via the second aperture.

The one or more light source may comprise a laser source.

Light received at the one or more light receiver may comprise light transmitted by the one or more light source which has been reflected by an object external to the internal volume of the housing. The sensor assembly may further comprise a processor configured to determine a time interval between light being transmitted by the one or more light source and the reflected light being received at the one or more light receiver to determine a distance between the sensor and the object.

The sensor may be independent to and supplied separately from the housing assembly as an 'off the shelf unit. The rotating clement of the sensor may rotate continuously over 360 degrees when in use. As such, it may also be required to rotate the housing continuously over 360 degrees in order to align the aperture with the field of view of the sensor. In some embodiments, the controller may be configured to synchronise rotation of the housing with rotation of the rotating element of the sensor such that the IS aperture is always aligned with the field of view of the sensor during at least a portion of a period of operation. This may require rotating the housing at the same speed as the rotating element of the sensor. In embodiments in which the housing assembly comprises the shutter, the controller configured to control the actuator to move the shutter between the closed position and the open position may be configured to control the actuator to cause the shutter to: adopt the open position when the aperture is aligned with a field of view of the sensor, and adopt the closed position when the aperture is not aligned with a field of view of the sensor.

The rotating clement of the sensor may rotate continuously over 360 degrees at several thousand rpm when in use. The housing is necessarily bigger than the sensor and may be much heavier, especially if the housing is metal, for example. As such, a great deal of energy may be required to overcome the inertia of the housing and rotate the housing at the same speed as the rotating element of the sensor. It may therefore be more practical to rotate the housing at a much slower speed than the rotating element of the sensor, perhaps in the region of a few hundred rpm or less. In such cases, the rotating element and the field of view of the sensor will not always be aligned with the aperture of the housing in use. As described above, the sensor may be configured to deliver pulses of light through the aperture of the housing and receive light passing into the internal volume of the housing through the aperture as the rotating element rotates.

As such, there will periods of time during rotation of the rotating element during which the sensor is not delivering or receiving light. In other words, there will be periods of time when light transmitted by the sensor simply bounces off an internal wall of the housing. The rotation of the housing can be controlled, by means of the motor and controller, to ensure that the rotating element of the light sensor is aligned with the aperture of the housing when the sensor is delivering and receiving light for at least part of a period of rotation of the rotating element and the housing. The controller can determine the moments in time that light received through the aperture is sensed by the sensor, and the angle in space that the received light comes from, and can build up a picture of the external environment by processing the detected signals. In embodiments in which the housing assembly comprises the shutter, the controller configured to control the actuator to move the shutter between the closed position and the open position may be configured to control the actuator to cause the shutter to adopt the closed position when the sensor is not delivering or receiving light.

In the example of a lidar sensor, the sensor may be configured to measure the length of time it takes a pulse of light, such as a laser pulse, to be received at the light receiver after being delivered form the light source. The light will hit an object after being delivered from the light source and will be reflected back towards the sensor.

The length of time taken for the light to be received at the light receiver can be used to determine a distance between the sensor and the object.

The controller may be configured to control the angular velocity of the housing. This may allow the angular velocity of the housing to be reduced in order to capture higher resolution image data.

The skilled person will appreciate that the sensor assembly may comprise any suitable combination of sensors, processors, memories and/or controllers required to carry out the above described functions. For example, the sensor assembly may further comprise a position sensor configured to output a signal indicative of an angular position of the housing. The angular position may be an angular position about an axis of rotation about which the motor is configured to rotate the housing. The angular position of the housing may be an angular position of the aperture about the axis of rotation relative to a predetermined initial position. The sensor assembly may further comprise a processor configured to receive the signal indicative of an angular position of the housing from the position sensor. The processor may be configured to process the signal indicative of an angular position of the housing to determine the angular position of the aperture relative to the field of view of the sensor. The processor may be configured to determine an angular velocity of the housing based on the signal indicative of the angular position of the housing. The processor may be configured to determine an amount of rotation required to rotate the housing to align the aperture with the field of view of the sensor. The processor may be configured to output a signal indicative of the amount of rotation. The controller may be configured to receive the signal indicative of the amount of rotation from the processor. The controller may be configured to control the motor to control rotation of the housing in dependence on the amount of rotation to align the aperture with a field of view of the sensor.

IS The processor configured to determine the angular position of the housing may be the same processor as that which is configured to determine a distance between the sensor and an object external to the housing.

Another aspect of the invention provides a method of obtaining image data using a sensor assembly according to an embodiment of the invention The sensor of the sensor assembly may comprise one or more light source and one or more light receiver. The sensor may be configured to transmit light from the one or more light source in a plurality of directions and receive light at the one or more light receiver from a plurality of directions. The light received at the one or more light receiver may comprise light transmitted by the one or more light source which has been reflected by an object external to the internal volume of the housing. The sensor assembly may further comprise a processor configured to determine a time interval between light being transmitted by the one or more light source and the reflected light being received at the one or more light receiver to determine a distance between the sensor and the object. The method comprises selecting a region of interest within a scene, controlling rotation of the housing to align the aperture of the housing with at least part of the region of interest, and determining a distance between the sensor and an object within the at least part of the region of interest. In this way, the aperture can be 'steered' to a region of interest within the surroundings of the sensor assembly. The sensor assembly can then be used capture image data from the region of interest.

In embodiments in which the housing assembly of the sensor assembly comprises the shutter, the method may comprise causing the shutter to adopt the open position when the aperture of the housing is aligned with at least part of the region of interest.

Another aspect of the invention provides a method of obtaining image data using a sensor assembly according to an embodiment of the invention. The sensor of the sensor assembly may comprise one or more light source and one or more light receiver. The sensor may be configured to transmit light from the one or more light source in a plurality of directions and receive light at the one or more light receiver from a plurality of directions. The light received at the one or more light receiver may comprise light transmitted by the one or more light source which has been reflected by an object external to the internal volume of the housing. The sensor assembly may further comprise a processor configured to determine a time interval between light IS being transmitted by the one or more light source and the reflected light being received at the one or more light receiver to determine a distance between the sensor and the object. The controller may also be configured to control the angular velocity of the housing relative to the sensor mount. The method comprises selecting a region of interest within a scene, rotating the housing at a first angular velocity when the aperture is aligned with a region of the scene which is not the region of interest, rotating the housing at a second angular velocity when the aperture is aligned with at least part of the region of interest, and determining a distance between the sensor and an object within the at least part of the region of interest. The second angular velocity is less than the first angular velocity. In this way, higher resolution image data can be captured from the region of interest by slowing the rotation of the housing.

Another aspect of the invention provides a method of obtaining image data using a sensor assembly according to an embodiment of the invention. The sensor of the sensor assembly may comprise one or more light source and one or more light receiver. The sensor may be configured to transmit light from the one or more light source in a plurality of directions and receive light at the one or more light receiver from a plurality of directions. The light received at the one or more light receiver may comprise light transmitted by the one or more light source which has been reflected by an object external to the internal volume of the housing. The sensor assembly may further comprise a processor configured to determine a time interval between light being transmitted by the one or more light source and the reflected light being received at the one or more light receiver to determine a distance between the sensor and the object. The controller may also be configured to control the angular velocity of the housing relative to the sensor mount. The method comprises selecting a region of interest within a scene, rotating the housing at a first angular velocity when the aperture is aligned with a region of the scene which is not the region of interest, controlling rotation of the housing to align the aperture of the housing with at least part of the region of interest, rotating the housing at a second angular velocity when the aperture is aligned with at least part of the region of interest, and determining a distance between the sensor and an object within the at least part of the region of interest. The second angular velocity is less than the first angular velocity. In this way, the aperture can be moved quickly past regions of lower interest, steered to a region of highcr interest, and then slowed down to allow the capture of higher resolution image data from the region of interest.

IS

In embodiments in which the housing assembly of the sensor assembly comprises the shutter, the method may comprise causing the shutter to: adopt the closed position when the aperture is aligned with a region of the scene which is not the region of interest, and adopt the open position when the aperture is aligned with at least part of the region of interest.

The sensor assembly may further comprise a processor configured to receive a signal indicative of an amount of rotation required to align the aperture with at least part of the region of interest. For example, a human operator may select the region of interest and provide the signal to the processor via an appropriate user interface. The processor configured to receive the signal may be the same processor which is configured to determine the angular position of the housing and/or determine a distance between the sensor and an object external to the housing.

Another aspect of the invention provides a self-propelled airsidc dolly comprising the sensor assembly of any of the embodiments described above. A self-propelled airside dolly may comprise an array of sensors, including a sensor responsive to electromagnetic radiation, to allow the dolly to operate in an autonomous mode. An airside dolly may operate in particularly harsh environments, such as in open airfields during severe weather. The sensor assembly of the present invention may therefore be particularly well suited to use with a self-propelled airside dolly; however, it will be appreciated that the invention is not limited to this use.

Another aspect of the invention provides an autonomous vehicle comprising the sensor assembly of any of the embodiments described above. The autonomous vehicle may comprise an autonomous personnel transport vehicle, such as a car or bus, or a vehicle not intended to carry personnel, such as an autonomous surveillance vehicle or the like.

Whilst a vehicle provided with a sensor assembly is envisaged, we also envisage the sensor assembly being provided on fixed equipment, for example a post, lamppost, gantry, roof, or wall. A sensor or camera watching a road junction is another example use.

Another aspect of the invention provides a method of retrofitting a self-propelled airside dolly with the sensor assembly of any of the above described examples. The method comprises fitting the sensor assembly to the self-propelled airside Another aspect of the invention provides a method improving the performance of a sensor responsive to electro-magnetic radiation by protecting the sensor from external forces, comprising receiving the sensor within the internal volume of the housing assembly of any of the above described embodiments

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings: Figure 1 shows a schematic cross-sectional isometric view of a housing assembly, for a sensor assembly, according to an embodiment of the invention; Figure 2 shows a schematic cross-sectional isometric view of another embodiment of the housing assembly of Figure 1; Figure 3 shows a schematic cross-sectional isometric view of another embodiment of the housing assembly of Figure 2; Figure 4 shows a schematic cross-sectional side view of the housing assembly of Figure 3, with some features omitted for clarity; Figure 5 shows a schematic cross-sectional side view of the housing assembly of Figure 4 Figure 6 shows a schematic cross-sectional isometric view of another embodiment of the housing assembly of Figure 2; Figure 7 shows a schematic cross-sectional isometric view of another embodiment of the housing assembly of Figure 2; Figure 8 shows a schematic side view of a housing assembly according to another embodiment of the invention; Figure 9 shows a schematic cross-sectional side view of a lidar sensor; Figure 10 shows a schematic cross-sectional side view of a sensor assembly according to an embodiment of the invention; Figure 11 shows a schematic cross-sectional plan view of the sensor assembly of Figure 10; Figure 12 shows a schematic of control elements of a sensor assembly according to an embodiment of the invention; Figure 13 shows a flowchart illustrating a method according to an embodiment of the invention; Figure 14 shows a schematic side view of a self-propelled airside dolly comprising a sensor assembly according to an embodiment of the invention; and Figure 15 shows a schematic cross-sectional isometric view of another embodiment of a housing assembly.

DETAILED DESCRIPTION

Figure 1 shows a schematic cross-sectional isometric view of a housing assembly 1 for a sensor assembly according to an embodiment of the invention. The housing assembly 1 comprises a housing 11, a motor 17, and a controller 18. The housing 12 comprises an outer wall 111 defining an internal volume 112 for receiving a sensor responsive to eleetro-magnetic radiation, and an aperture 113 arranged in the outer wall III to allow light to pass into the internal volume 112. The motor 17 is configured to rotate the housing relative to the sensor mount 12. The controller 18 is configured to control the motor 17 to control rotation of the housing 11 to align the

aperture with a field of view of the sensor. Li

Figure 2 shows a schematic cross-sectional isometric view of another embodiment of the housing assembly 1 of Figure 1. The embodiment of Figure 2 shares the same features of the embodiment of Figure 1, with like reference numerals used to refer to like features. The housing assembly 1 comprises a housing 11, and a sensor mount 12 for a sensor responsive to electro-magnetic radiation, a motor 17, and a controller 18. The sensor mount 12 is arranged within an internal volume 112 of the housing. The housing 11 is rotatable relative to the sensor mount 12 about an axis of rotation at. The housing 12 comprises an outer wall 111 defining the internal volume 112 and an aperture 113 arranged in the outer wall 111 to allow light to pass into the internal volume 112. The motor 17 is configured to rotate the housing relative to the sensor mount 12 about the axis of rotation at. The axis of rotation at is parallel to the plane of the aperture 113. In other embodiments, the axis of rotation at may be oblique, i.e. not parallel and not perpendicular, to the plane of the aperture 113. The controller 18 is configured to control the motor 17 to control rotation of the housing 11 about the axis of rotation at.

Figure 3 shows a schematic cross-sectional isometric view of another embodiment of the housing assembly 1 of Figure 2. The embodiment of Figure 3 shares the same features of the embodiment of Figure 2, with like reference numerals used to refer to like features.

The housing assembly 1 of Figure 3 further comprises an opening 114 to allow air to pass into the internal volume 112 to create a positive pressure gradient between the aperture 113 and the opening 114 when the housing II is rotated relative to the sensor mount 12 by the motor 17.

The purpose of the housing assembly 1 is to provide robust protection for a sensor responsive to clectro-magnetic radiation that may be received within the internal volume 112, for example mounted to the sensor mount 12, in use, while still allowing the sensor to function as required. In use, the housing 11 protects the sensor from precipitation, such as rain or snow, and other damage. in the embodiment of Figure 3, rotating the housing 11 forces air into the internal volume 112 through the opening 114 to generate a pressure differential between the internal volume 112 and outside the housing 11, with the pressure of the internal volume 112 being greater than the pressure outside the housing I I. For example, the pressure outside the housing I I may be atmospheric pressure and the pressure of the internal volume 112 may be greater than atmospheric pressure when the housing 11 is rotated. This inhibits ingress of precipitation or other material into the internal volume 112 of the housing 11 through the aperture 113. The aperture 113 allows light to pass into the internal volume 112, allowing the sensor to function as required In the embodiments of Figures 1 to 3, the housing 11 is cylindrical; however, it will be appreciated that the cross-section of the housing may be any suitable shape.

Figures 1 to 3 show the intended orientation of the housing assembly 1 when it is installed in use. As shown, the outer wall 111 extends over the top of the housing 11 to prevent ingress of falling material, such as precipitation or debris, into the internal volume 112. The outer wall 111 may be formed from separate sections joined together, or may be a continuous formed piece of material. In the embodiment of Figure 2, the entire underside of the housing I I is open to provide the opening 114 in other embodiments, the opening 114 may be provided elsewhere on the housing 11, for example in the outer wall 111. The aperture 113 is illustrated as a narrow slit, which may be particularly suitable for use with sensors having a tall, narrow field of view, such as lidar sensors. However, in other embodiments the shape and dimensions of the aperture 113 may be different. It will be appreciated that the shape and dimensions of the aperture 113 will be dependent on the particular sensor used with the housing assembly 1 in use.

Preferably the outer wall 111 of the housing 11 is metal, or another suitably robust material. The aperture 113 allows the outer wall 111 to be formed from an opaque material. Transparent materials are typically less robust than opaque materials.

In the embodiments of Figures 2 and 3, the sensor mount 12 comprises a bracket 121, a shaft 122 and a bearing 123. The bracket 121 is configured such that a suitable sensor can be attached to the bracket 121 in use. The bearing 123 is fixed to the ceiling of the outer wall 111 of the housing 11 and to a first end of the shaft 122. The bearing 123 is configured to allow the housing 11 to rotate relative to the shaft 122. The bracket 121 fixed to the other end of the shaft 122, such that the housing 11 is rotatable relative to the bracket 121. In other embodiments, the sensor mount 12 may be configured differently. The housing 11 and sensor mount 12 may be configured in any suitable way to allow the housing 11 to rotate relative to the sensor mount 12. The housing assembly 1 may comprise any suitable arrangement of bearings, gimbals or other means to allow the housing II to rotate relative to the sensor mount 12.

Figure 4 shows a schematic cross-sectional isometric view of another embodiment of the housing assembly 1 of Figure 3. The embodiment of Figure 4 shares the same features of the embodiment of Figure 3, with like reference numerals used to refer to like features. Some of the features of the housing assembly I, including the sensor mount 12, the motor 17 and the controller 18, have been omitted in Figure 4 for clarity.

The housing assembly 1 of Figure 4 further comprises an impeller 15 configured to rotate with the housing 11 and located within an airflow between the opening 114 and the aperture 113 in use. In the embodiment of Figure 4, the impeller 15 comprises two blades; however, in other embodiments the impeller 15 may comprise more or fewer blades. In the embodiment of Figure 4, the blades are fixed together via a central hub, with the ends of the blades distal from the hub being fixed to an internal wall of the housing 11. The impeller 15 therefore rotates together with the housing 11 relative to the sensor mount 12. The impeller 15 is located just inside the opening 114; however, in other embodiments the impeller 15 may be spaced further from the opening 114.

The impeller 15 is provided to encourage air to flow into the internal volume 112 of the housing I [through the opening 114 when the housing 11 is rotated, thereby pressurising the internal volume 112.

Figure 5 shows a schematic cross-sectional side view of the housing assembly 1 of Figure 4. In use, the housing 11 is rotated about the axis ai by the motor 17, while the sensor mount 12 remains stationary relative to the housing 11. This rotation of the housing 11 causes air to be drawn into the internal volume 112 of the housing 11 by means of the impeller 15 or, where the impeller 15 is not present, by means of rotation of the housing 11 alone. The arrows in Figure 5 indicate the direction of air flow into the internal volume 112 of the housing 11. This flow of air pressurises the internal volume 112, inhibiting ingress of precipitation or other material into the internal volume 112 through the aperture 113. It will be appreciated that although the axis of rotation al of the housing 11 is shown as a vertical axis in Figure 5, the housing assembly 1 may adopt any suitable orientation in use. For example, the housing assembly I may be installed in use such that the axis of rotation al of the housing I I is horizontal Figure 6 shows a schematic cross-sectional isometric view of another embodiment of the housing assembly 1 of Figure 3. The embodiment of Figure 6 shares the same features of the embodiment of Figure 3, with like reference numerals used to refer to like features. Some of the features of the housing assembly I have been omitted in Figure 6 for clarity.

The housing assembly 1 of Figure 6 further comprises a lip 16 projecting from the outer wall 111 of the housing 11 away from the internal volume 112 of the housing 11 in a direction perpendicular to the plane of the aperture 113. The lip 16 is provided to inhibit precipitation or other material from falling into the internal volume 112 of the housing 11 through the aperture 113 in use. The lip 16 is configured such that it is located above the aperture I 13 when the housing assembly 1 is installed as intended in use. The lip 16 of the embodiment of Figure 6 extends perpendicularly to the plane of the aperture 113; however, in other embodiments the lip 16 may extend at a non-right angle to the plane of the aperture 113. For example, the lip 16 may slope downwards when the housing assembly 1 is installed to encourage precipitation to drain from the roof of the housing I. The housing assembly 1 of Figures I or 2, in which the opening 114 is not present, may also utilise the lip 16 in the same way as the embodiment of Figure 6.

Figure 7 shows a schematic cross-sectional isometric view of another embodiment of the housing assembly 1 of Figure 3. The embodiment of Figure 7 shares the same features of the embodiment of Figure 3, with like reference numerals used to refer to like features. Some of the features of the housing assembly I have been omitted in Figure 7 for clarity.

In the embodiment of Figure 7, the aperture 113 comprises a first aperture 113a and the housing 11 further comprises a second aperture 113b arranged in the outer wall 111 to allow light to pass into the internal volume 112. The second aperture II 3b is provided to increase the amount of light which passes into the internal volume 112 in use and/or to allow light to pass into the internal volume 112 from a different angle with respect to the sensor mount 12. The first and second apertures 113a. b are arranged opposite each other in the outer wall 1 1 1 of the housing 11. in other embodiments, the housing 1 may comprise more than two apertures 113 arranged in the outer wall 111. It vill be appreciated that the number and arrangement of apertures 113 will depend on the particular use of the housing assembly 1, including the type of sensor that is mounted to the sensor mount 12 in use and the type of data that is to be collected or measured by the sensor. The housing assembly 1 of Figures 1 or 2, in which the opening 114 is not present, may &so utilise the first and second apertures 113a, 1136 in the same way as the embodiment of Figure 7, Figure 8 shows a schematic side view of a housing assembly 2 according to another embodiment of the invention. The housing assembly 2 of Figure 8 shares the same features of the housing assembly 1 any of the above described embodiments, with like reference numerals used to refer to like features. Some of the features of the housing assembly 2 have been omitted in Figure 8 for clarity.

The housing assembly 2 of Figure 8 comprises a post 21. The housing 11 of the housing assembly 2 is mounted to the post 21 such that the housing 11 is rotatable relative to the post 21. The post 21 comprises a surface 211, such that the housing 11 is rotatable relative to the surface 211. The housing 11 and the surface 211 are arranged such that aperture 113 of the housing 11 is aligned with the surface 211 at a predetermined angular position of the housing 11. When the aperture 113 is aligned with the surface 211, the surface 211 substantially covers the aperture 113. The gap between the housing 11 and the surface 211 may be minimised such that when the aperture 113 is aligned with the surface 211, the aperture 113 is substantially inaccessible. The controller 18 is configured to control rotation of the housing 11 to adopt a stationary position at which the aperture 113 is aligned with the surface 211. This may be referred to as a 'park' position of the housing II. For example, the housing 11 could be controlled to adopt the park position when not in use.

In other embodiments, the post 21 may be replaced by another fixed structure such as a building. In use, the housing assembly 2 of Figure 8 may be positioned at a location of interest such as a road junction.

Figure 9 shows a schematic cross-sectional side view of a lidar sensor 10 which could be mounted to the sensor mount 12 of any embodiment of the housing assembly 1, 2 described herein. The lidar sensor 10 is representative of known lidar sensors. The lidar sensor 10 comprises a first housing 101, a second housing 102, a mirror 103, a light source 104, in the form of a laser, a light receiver 105 and a lens 106. The first housing 101 is configured to rotate relative to the second housing 102 about an axis of rotation az. The lidar sensor 10 further comprises a motor (not shown) to rotate the first housing 101. The mirror 103 is housed in the first housing 103 and is fixed to rotate with the first housing about the axis of rotation am The lens 106 is arranged in a wall of the first housing 101 to allow light to pass out from and in to the first housing 101. The light source 104 and the light receiver 105 are housed within the second housing 102. The first and second housings 101, 102 are configured such that light can pass between them. In use, light is transmitted from the light source 104 to the mirror 103. The light is then reflected by the mirror 103 and out through the lens 106. The light will then hit an object within the surroundings of the lidar sensor 10 and be reflected by the object back towards the lidar sensor 10. The light is then collected by the lens 106 and reflected by the mirror 103 towards the light receiver 105.

The light source 104 is configured to deliver pulses of light as the mirror 103 rotates with the first housing 101. As such, the lidar sensor delivers and receives light at predetermined angular intervals as the mirror 103 rotates. In use, the lidar sensor 10 would be in communication with one or more processors configured to measure the time between light leaving the light source 104 and being received by the light receiver 105 after having been reflected by an object in the sensor's surroundings. The measured time can then be used to calculate the distance between the lidar sensor 10 and objects in its surroundings to build a three-dimensional picture of the sensor's surroundings.

It will be appreciated that the lidar sensor 10 may comprise any suitable arrangement of further mirrors and lenses (not shown) required to build a three-dimensional picture of the sensor's surroundings.

Figure 10 shows a schematic cross-sectional side view of a sensor assembly 20 according to an embodiment of the invention. The sensor assembly 20 comprises the housing assembly 1 of Figure 5 and the lidar sensor 10 of Figure 9 mounted on the sensor mount 12 of the housing assembly 1. Other embodiments of the invention may provide a sensor assembly comprising the housing assembly of any of the embodiments described herein and any suitable sensor. For clarity, features of the lidar sensor 10 are omitted from Figure 10.

The lidar sensor 10 may be mounted to the sensor mount 12 via the second housing of the lidar sensor 10 as shown in Figure 8. The lidar sensor 10 is therefore mounted in an upside-down orientation with respect to the view of Figure 9. In the embodiment of Figure 10, the axes of rotation of the first housing of the lidar sensor 10 and the housing II of the housing assembly I are concentric; however, in other embodiments they may be offset. In some embodiments, the axis of rotation of the first housing of the lidar sensor 10 may be perpendicular to the axis of rotation of the housing assembly 1.

The first housing, and therefore the mirror, of the lidar sensor 10 is therefore configured to rotate within the internal volume 112 of the housing 11 as the housing 11 rotates relative to the sensor mount in use 12. The lidar sensor 10 may be configured to rotate at a different angular velocity than the housing 11. The lidar sensor 10 may be an 'off the shelf' unit with the mirror configured to rotate at a fixed angular velocity, and the inertia of the housing 11 may be significantly greater than that of the rotating elements of the lidar sensor 10.

As described above, the lidar sensor 10 is configured to deliver pulses of light and receive reflected light, resulting from the light pulses, after the light has been reflected by an object in the surroundings of the lidar sensor 10. it is therefore necessary for the mirror of the lidar sensor 10 to be aligned with the aperture 113 of the housing 11 when the light source of the lidar sensor 10 delivers a pulse of light to allow light to be delivered from and received by the lidar sensor 10. To achieve this, the controller 18 is used to control rotation of the housing II to ensure that the aperture 113 of the housing is aligned with the mirror of the lidar sensor 10 when the light source of the lidar sensor 10 delivers a light pulse at one or more angular positions of the housing 11 during rotation of the housing 11.

Figure 11 shows a schematic cross-sectional plan view of the sensor assembly 20 of Figure 10. The housing 11 of the housing assembly is shown in a position in which the aperture 113 is aligned with the lens 106 and the mirror 103 of the lidar sensor 10.

Figure 11 also shows the common axis of rotation ai,7 of the housing 11 and mirror 103. The field of view of the lidar sensor 10 is illustrated using dashed lines in Figures 10 and 11 It will be appreciated that in the above described example, the mirror of the lidar sensor 10 is the rotating element of the lidar sensor 10. In other embodiments, the lidar sensor may not comprise a mirror, and the light source itself may be configured as the rotating element. The above described example is merely one example of how a optical sensor comprising a rotating element configured to transmit light may work in a sensor assembly according to the invention.

It will be appreciated that in some embodiments of the sensor assembly, a motion blurring effect may be present in data captured by the optical sensor as a result of rotation of the housing. There may also be parts of the data captured by the optical sensor which are not useful; for example, where light reflected by an internal wall of the housing is captured by the optical sensor. In these cases, software can be used to minimise or remove the motion blurring effect and remove the parts of the data which are not useful. This may comprise 'stitching together' useful parts of the data to provide an image. The sensor assembly of any of the embodiments described herein may therefore be provided with a processor configured to implement software to achieve the above objectives.

Figure 12 shows a schematic of control elements of a sensor assembly 20 according to an embodiment of the invention. The lines between elements indicate electrical communication provided between elements. The sensor assembly 20 comprises a position sensor 19 configured to output a signal indicative of an angular position of the housing. The position sensor 19 may comprise any suitable optical, electrical, or mechanic& position sensor. The sensor assembly 20 further comprises a processor 110 configured to receive the signal indicative of an angular position of the housing. in this embodiment, the processor 110 is also configured to receive signals form the lidar sensor 10 indicative of reflected light received and the light receiver of the lidar sensor 10. The processor 110 is configured to process these signals from the lidar sensor 10 to determine a distance between the lidar sensor 10 and an object, as described above. In other embodiments, the sensor assembly 20 may comprise a separate processor configured to carry out this function.

The processor [10 is further configured to process the signal indicative of an angular position of the housing to determine the angular position of the aperture relative to the field of view of the sensor. The processor 110 is also configured to determine an angular velocity of the housing based on the signal indicative of the angular position of the housing. The processor 110 is configured to determine an amount of rotation required to rotate the housing to align the aperture with the field of view of the lidar sensor 10 and output a signal indicative of the amount of rotation. The controller 18 is configured to receive the signal indicative of the amount of rotation from the processor 110, and control the motor 17 to control rotation of the housing in dependence on the amount of rotation to align the aperture with the field of view of the lidar sensor 10.

The processor 110 may also be considered to receive control inputs, for example from a human operator via an appropriate user interface or an autonomous vehicle controller. These inputs may be processed by the processor 110, and the processor 110 may produce corresponding control signals to operate the sensor assembly 20 accordingly. In other embodiments, a separate controller may be provided to receive and process control inputs.

The sensor assembly 20 further comprises a memory 201 in communication with the processor 110. The memory 201 comprises instructions which, when executed by the processor, can carry out any of the functions of the sensor assembly 20 described herein.

The skilled person will appreciate that the control arraignment of Figure 11 is merely illustrative and that the sensor assembly 20 may comprise any suitable arrangement of control elements, including controllers, processors, sensors and memories, required to carry out any of the functions of the sensor assembly 20 described herein.

Figure 13 shows a flowchart illustrating a method 30 according to an embodiment of the invention. The method 30 is a method of obtaining image data using the sensor assembly 20 of Figures 10 and I I. or any other sensor assembly according to the invention in which rotation of the housing can be controlled to control the angular position and angular velocity of the housing.

The method 30 begins at step 301, which comprises selecting a region of interest within a scene. In this example, the scene is the surroundings of the sensor assembly. The region of interest may, for example, contain a particular object of which it is desired to capture image data of Selecting the region of interest may comprise a human operator or an autonomous control system providing a control input to the sensor assembly.

The method 30 then proceeds to step 302, which comprises rotating the housing at a first angular velocity, for example by means of the motor and controller where present, when the aperture of the housing is aligned with a region of the scene which is not the region of interest. The method 30 then proceeds to step 303, which comprises controlling rotation of the housing to align the aperture of the housing with at least part of the region of interest. The method 30 then proceeds to step 304, which comprises rotating the housing at a second angular velocity when the aperture is aligned with at least part of the region of interest. The method 30 then proceeds to step 305, which comprises determining a distance between the sensor of the sensor assembly and an object within the at least part of the region of interest. The second angular velocity is less than the first angular velocity. In other embodiments, one of steps 303 or 304 may not be required and may be omitted.

At the start of the method 30, the aperture of the housing may not be aligned with the region of interest. This may be during rotation of the housing or when the housing is stationary. At step 302, the housing is controlled to rotate at a first angular velocity towards a position at which the aperture is aligned with at least part of the region of interest Once the aperture is aligned with at least part of the region of interest, the angular velocity of the housing is reduced to enable higher resolution image data to be obtained by the sensor. The housing may optionally be brought to a stationary position between rotating the housing at the first angular velocity to align the aperture, before beginning rotation again at the second, slower angular velocity. The aperture is therefore 'swept' past regions of lower interest at a greater angular velocity before slowing rotation of the housing to obtain image data of the region of interest.

Figure 14 shows a schematic side view of a self-propelled airside dolly 40 comprising the sensor assembly 20 of any of the embodiments described herein. The sensor assembly 20 may be utilised to enable an autonomous mode of operation of the dolly in accordance with methods known in the art. The dolly 40 further comprises a main body or chassis 401, a plurality of wheels 402 and a cargo arca 403. The plurality of wheels 402 are driven by a powertrain (not shown) to enable the dolly 40 to travel around an environment, such as an airport or airfield. The cargo area 403 is provided for securing cargo, such as passenger luggage or a unit load device (ULD), to the dolly 40 for transportation by the dolly 40. It will be appreciated that dolly 40 is just one example of how the sensor assembly 20 of the present invention could be utilised.

Figure 15 shows a schematic isometric view of a housing assembly 3, for a sensor assembly, according to another embodiment. The housing assembly 3 has features in common with the housing assembly 1 of Figure 2, with like reference numerals used to refer to like features.

I5 The housing assembly 3 of Figure I5 differs from the housing assembly 1 of Figures 1 to 3 in that the motor and controller are not necessarily provided. The housing assembly 3 of Figure 15 comprises a rotation mechanism (not shown) configured to rotate the housing 11 relative to the sensor mount 12 to create a positive pressure gradient between the aperture 113 and the opening 114. The rotation mechanism comprises any suitable means to rotate the housing 11 relative to the sensor mount 12.

This may comprise the motor and/or controller of the housing assembly 1 of Figures 1 to 3, or one or more vanes rotationally fixed relative to the housing, such that the housing is configured to rotate under the power of the wind, for example. The housing assembly 3 of Figure 15 can be used with any suitable sensor responsive to electro-magnetic radiation. For example, a basic light sensor configured to measure a light level could be used. In such an example, it doesn't matter which direction light received by the sensor comes from. Therefore, the angular position of the aperture 113 of the housing 1 I relative to the sensor mount 12 is not important, as long as light is able to pass through the aperture 113 into the internal volume 112 of the housing 11.

Each concept discussed in the present disclosure, except where otherwise provided, may be utilised independently or in combination with any other concept discussed. The skilled person will understand that the specific examples discussed are simply embodiments of the discussed concepts for illustrative purposes and that combinations disclosed in relation to one specific example are not intended to limit the different combinations that could be provided without departing from the scope of the disclosure.

Where an aspect of the disclosure is discussed in relation to a baggage dolly, unless otherwise necessary any feature of the described baggage dolly may be provided as part of a vehicle, such as a land vehicle, water vehicle, air vehicle, or road vehicle.

Claims

CLAIMS1. A housing assembly for a sensor assembly, comprising: a housing comprising: an outer wall defining an internal volume for receiving a sensor responsive to electro-magnetic radiation; and an aperture arranged in the outer wall to allow light to pass into the internal volume; a motor configured to rotate the housing; and a controller configured to control the motor to control rotation of the housing to align the aperture with a field of view of the sensor.
2. The housing assembly of claim I. wherein the aperture comprises a first opening configured to allow air to pass out of the internal volume and the housing further comprises a second opening configured to allow air to pass into the internal volume to allow a positive pressure gradient between the first opening and the second CJ opening when the housing is rotated by the motor. a)
0 3. The housing assembly of claim 2, comprising an impeller configured to rotate with the housing and arranged between the first opening and the second opening such 0 that the impeller is located within an airflow between the second opening and the first opening when the housing is rotated by the motor.
4. The housing assembly of claim 2 or claim 3, comprising an air filter arranged between the first opening and the second opening such that the air filter is located within an airflow between the second opening and the first opening when the housing is rotated by the motor.
The housing assembly of any preceding claim, wherein the outer wall is metal.
6. The housing assembly of any preceding claim, comprising a heater configured to heat air within the internal volume.
7. The housing assembly of any preceding claim, comprising a cooler configured to cool air within the internal volume.
8. The housing assembly of any preceding claim, wherein the housing comprises a further aperture arranged in the outer wall to allow light to pass into the internal volume, wherein the controller is configured to control the motor to control rotation of the housing to align the further aperture with a field of view of the optical sensor.
9. The housing assembly of claim 8, wherein the motor is configured to rotate the housing about an axis of rotation and the further aperture is spaced apart from the aperture about the axis of rotation by ISO degrees.
10. The housing assembly of any preceding claim, wherein the housing comprises a lip projecting from the outer wall away from the internal volume.
11. The housing assembly of any preceding claim, comprising an external surface outside the internal volume of the housing, wherein the motor is configured to rotate the housing relative to the external surface, wherein the external surface is configured C\I to cover the aperture when the aperture is aligned with the external surface, wherein a) the controller is configured to control the motor to control rotation of the housing to adopt a stationary position at which the aperture is aligned with the external surface.
0 12, A sensor assembly comprising the housing assembly of any preceding claim and a sensor responsive to electro-magnetic radiation received within the internal volume, wherein the controller is configured to control the motor to control rotation of the housing to align the aperture with a field of view of the sensor received within the internal volume.
13. The sensor assembly of claim 12, wherein the sensor comprises one or more light source and one or more light receiver, wherein the controller is configured to control the motor to control rotation of the housing to align the aperture to transmit light from the one or more light source and receive light at the one or more light receiver.
14. The sensor assembly of claim 13, wherein the one or more light source is configured to transmit light in a plurality of directions and the one or more light receiver is configured to receive light from a plurality of directions, wherein the controller is configured to control the motor to control rotation of the housing to align the aperture to transmit light from the one or more light sourcc in each of thc plurality of directions and receive light at the one or more light receiver from each of the plurality of directions.
15. The sensor assembly of claim 14, wherein the sensor comprises a rotating element configured to rotate to change the direction in which light is transmitted from the one or more light source and change the direction from which light is received at the one or more light receiver, wherein the controller is configured to control rotation of the housing to synchronise rotation of the housing with rotation of the rotating element to align the aperture to transmit light from the one or more light source in each of the plurality of directions and receive light at the one or more light receiver from each of the plurality of directions
16. The sensor assembly of any one of claims 12 to 15, wherein the sensor comprises a lidar sensor.
17. The sensor assembly of any one of claims 12 to 16, wherein the controller configured to control the angular velocity of the housing 20
18. The sensor assembly of claim 13, or any one of claims 14 to 17 when dependent on claim 13, wherein light received at the one or more light receiver comprises light transmitted by the one or more light source which has been reflected by an object external to the internal volume of the housing, wherein the sensor assembly further comprises a processor configured to determine a time interval between light being transmitted by the one or more light source and the reflected light being received at the one or more light receiver to determine a distance between the light sensor and the object
19. A method of obtaining image data using the sensor assembly of claim 18, comprising: selecting a region of interest within a scene; controlling rotation of the housing to align the aperture of the housing with at least part of the region of interest; and determining a distance between the sensor and an object within the at least part of the region of interest.
20. A method of obtaining image data using the sensor assembly of claim 18 when dependent on claim 17, comprising: selecting a region of interest within a scene; rotating the housing at a first angular velocity when the aperture is aligned with a region of the scene which is not the region of interest; rotating the housing at a second angular velocity when the aperture is aligned with at least part of the region of interest, wherein the second angular velocity is less than the first angular velocity; and determining a distance between the sensor and an object within the at least part of the region of interest.
21. A method of obtaining image data using the sensor assembly of claim 18 when dependent on claim 17, comprising: C\I selecting a region of interest within a scene; a) rotating the housing at a first angular velocity when the aperture is aligned 0 with a region of the scene which is not the region of interest; controlling rotation of the housing to align the aperture of the housing with at 0 least part of the region of interest; rotating the housing at a second angular velocity when the aperture is aligned with the at least part of the region of interest, wherein the second angular velocity is less than the first angular velocity; and determining a distance between the sensor and an object within the at least part of the region of interest.
22. A self-propelled airside dolly comprising the sensor assembly of any one of claims 12 to 18.
23. A method of retrofitting a self-propelled airside dolly with the sensor assembly of any one of claims 12 to 18, comprising fitting the sensor assembly to the self-propelled airside dolly. C\I a)
24. A method of improving the performance of a sensor responsive to electromagnetic radiation by protecting the sensor from external forces, comprising receiving the sensor with the internal volume of the housing assembly of any one of claims 1 to I I.
25. A housing assembly for a sensor assembly, comprising: a housing comprising: an outer wall defining an internal volume for receiving a sensor responsive to electro-magnetic radiation; an aperture arranged in the outer wall to allow light to pass into the internal volume; and an opening to allow air to pass into the internal volume; and a rotation mechanism configured to rotate the housing to create a positive pressure gradient between the aperture and the opening
26. A housing assembly for a sensor assembly comprising a housing, a shutter, an actuator, and a controller, the housing comprising an outer wall defining an internal volume for receiving a sensor responsive to electro-magnetic radiation or other signals, and an aperture arranged in the outer wall to allow light to pass into the internal volume, the shutter being configured to move between a dosed position, in which the shutter covers the aperture, and an open position, in which the shutter uncovers the aperture, and the actuator being configured to move the shutter between the closed position and the open position, and the controller being configured to control the actuator to sequentially move the shutter between the closed position and the open position.