Portable reference sensor system and vehicle with a portable reference sensor system

Abstract

Portable reference sensor system comprising at least one optical sensor, at least one position sensor and a computing unit designed and configured to process sensor data from the at least one optical sensor and the at least one position sensor, wherein the portable reference sensor system has a rigidly designed base plate, wherein the sensors and the computing unit are each directly or indirectly connected to the base plate.

Description

[0001] The invention relates to a portable reference sensor system comprising at least one optical sensor, at least one position sensor, and a computing unit designed and configured to process sensor data from the at least one optical sensor and the at least one position sensor. Furthermore, the invention relates to a vehicle having a portable reference sensor system.

[0002] The statistical analysis of large volumes of representative real-world driving data to evaluate the performance of advanced driver assistance system (ADAS) sensors and their algorithms becomes increasingly crucial the higher the level of automation (SAE Levels 0 to 5) of a vehicle. Objective comparison of sensor signals against an absolute environmental reference is the only way to achieve cost-effective and reliable sensor development and validation. Manufacturer-independent, standardized reference sensor systems are nevertheless a basic prerequisite for the homologation / type approval of future automated vehicles, as the relevant certification authorities will always base their assessments on their own environmental image.US companies like Waymo and Uber, which view the technological advancement toward autonomous driving as a crucial component of their business model, consistently pursue a data-driven development approach to continuously improve and optimize their products. Every further development, every new iteration of their products, is constantly tested against the existing database and continuously optimized based on the resulting analysis results.

[0003] Crucial to autonomous vehicle driving are the vehicle sensors or the vehicle sensor system, which is capable of detecting, understanding, and reconstructing the static and dynamic environment of a vehicle. Each vehicle sensor in the vehicle sensor system uses its own coordinate system, in which at least a section of the environment is recorded within the respective detection range of the sensor. In order to be able to reconstruct the entire vehicle environment and to establish a geometric relationship between the respective coordinate systems of the sensors, it is necessary that the relative positions between all sensors in the vehicle sensor system and the vehicle are determined and calibrated.

[0004] For the development, calibration, and validation of vehicle sensor systems or vehicles that include a vehicle sensor system, the state of the art uses a uniform, portable reference sensor system for all vehicles. First, any vehicle is equipped with the reference sensor system. In order to be able to compare the sensor signals of the vehicle sensor system with the sensor signals of the reference sensor system, the next step is to calibrate the reference sensor system to the vehicle or to determine the position of the portable reference sensor system relative to the vehicle. In the current state of the art, an external calibration device, such as a motion capture system, is used for this purpose. The disadvantage of calibration using an external calibration device is that the calibration is tedious and time-consuming.Managing a large-scale measurement series is particularly challenging, especially for large vehicle fleets, which are necessary to generate the required amount of sensor data during driving in a wide variety of vehicle environments (climatic conditions, weather, road conditions, traffic situations, etc.). The portable reference sensor system and the external calibration device represent the limiting resources. Once all sensors in the vehicle sensor system and all sensors in the reference sensor system are calibrated to each other, or their relative positions are known, the respective sensor data can be recorded and compared.

[0005] To ensure that the sensor signals correspond to the actual environment, it is necessary that the sensor signals can be recorded as accurately as possible. Vibrations of the portable reference sensor system can lead to distorted sensor signals and the calibration of the reference sensor system becoming incorrect.

[0006] In existing reference sensor systems, the reference technology is often integrated into the vehicle chassis or a profile structure. Pre-calibration of the systems is not possible.

[0007] It is therefore the object of the present invention to provide a portable reference sensor system that overcomes the disadvantages of the portable reference sensor system compared to a vehicle in the prior art.

[0008] This object is achieved by a portable reference sensor system having the features of patent claim 1. Advantageous embodiments emerge from the subclaims.

[0009] The core idea of ​​the invention is to provide a portable reference sensor system with at least one optical sensor, at least one position sensor, and a computing unit designed and configured to process sensor data from the at least one optical sensor and the at least one position sensor. According to the invention, the portable reference sensor system comprises a rigid base plate. The sensors and the computing unit are preferably each connected directly or indirectly to the base plate.

[0010] A direct connection can be understood as meaning that the corresponding element is connected to the base plate without any additional intermediate elements. An indirect connection can be understood as meaning that the respective element is connected to the base plate by means of another element, for example, by means of spacers or the like.

[0011] The following can be understood as a rigid base plate or rigid base plate.

[0012] In principle, translational and / or rotational movements are conceivable for elements, with the corresponding degrees of freedom in each spatial direction, for example, represented by Cartesian coordinates. A rigid base plate is designed such that movements in the three spatial directions are essentially prevented, i.e., dependent on possible forces, tolerances, or the like. The base plate is intended and designed to be mounted on a vehicle and to prevent movements during (normal) vehicle operation. Movements in spatial directions can be permitted up to a certain deflection value, for example, a maximum of 1 mm, preferably less.

[0013] Particularly preferably, the base plate has a lower surface and / or an upper surface. Further preferably, the surfaces can each be at least partially flat, with the flat sections preferably lying in one plane.

[0014] The optical sensors can be cameras and multiple LIDAR sensors. It is further preferred that the at least one position sensor is a dGPS or GNSS. Particularly preferably, the at least one position sensor is part of a positioning system.

[0015] According to a preferred embodiment, the portable reference sensor system is designed and constructed to be attached to a vehicle.

[0016] The vehicle typically has its own coordinate system, the origin of which is usually defined at the center of the vehicle's rear axle. The vehicle's coordinate system is typically oriented such that the three axes are directed in a forward direction, an elevation direction, and a lateral direction, each of which is orthogonal to each other. The portable reference sensor system also has its own coordinate system.

[0017] Typically, the three axes of the reference sensor system are directed in a forward direction, a height direction, and a lateral direction. In order to determine the position of the reference sensor system relative to the vehicle, it is particularly necessary to determine a displacement or translation (e.g., using a vector) of the origin of the reference sensor system's coordinate system to the origin of the vehicle's coordinate system, particularly with millimeter accuracy. Furthermore, it is necessary to determine a rotation of the reference sensor system's coordinate system relative to the vehicle's coordinate system. Ideally, the two coordinate systems do not rotate relative to each other, but small deviations are possible; it is necessary to determine deviations on the order of one-tenth of a degree.

[0018] A deviation between the reference coordinate system and the vehicle coordinate system in terms of an angular error is the critical error to consider, as this error scales with distance. An error of 1° between the reference coordinate system and the vehicle coordinate system corresponds to a lateral deviation of 1.75 meters at a distance of 100 meters.

[0019] As a requirement, a maximum angular error of 0.2° is therefore considered acceptable.

[0020] Therefore, it is provided according to the invention that such a calibration or adjustment of the reference sensor system with respect to the vehicle remains unchanged due to the rigid base plate, i.e. that the positions of the sensors are correct and the sensor data can then also be correspondingly correct.

[0021] According to a preferred embodiment, the base plate may be made of a material with good thermal conductivity. Further preferably, the sensors and / or the computing unit may be thermally conductively connected to the base plate.

[0022] Good thermal conductivity can be understood as a thermal conductivity of at least 15 W / (m*K).

[0023] Examples of such materials for the base plate include stainless steel, aluminum, aluminum alloys, or the like. In principle, any material that can meet the requirements for thermal conductivity and rigidity can be used.

[0024] Because the base plate is made of a thermally conductive material, it can also be considered a heat sink. Heat generated, for example, by the computing unit is absorbed by the base plate and dissipated by the computing unit, thus cooling the computing unit.

[0025] According to a further preferred embodiment, it can be provided that the reference sensor system has a housing element which is intended and designed to be connected to the base plate, whereby a housing is represented by the housing element and the base plate.

[0026] By providing a housing, sensitive components can be protected from wind, light, rain, etc. Particularly preferably, the housing is sealed against liquids.

[0027] At least it is preferably provided that the computing unit is arranged within the housing.

[0028] According to a further preferred embodiment, it can be provided that the housing element has at least one opening, preferably several openings, through which the sensors can extend at least partially outwards.

[0029] For example, if the optical sensors are LIDArs or cameras, it is necessary for the functionality of these optical sensors that they extend at least partially out of the housing so that corresponding data or sensor data can be recorded.

[0030] According to a further preferred embodiment, it can be provided that the housing element comprises a housing element part which is detachably connected to the housing element.

[0031] This housing element part allows a portion of the housing element to be removed, eliminating the need for complete disassembly if something inside the housing needs to be changed or replaced. This provides easy access to the interior of the housing.

[0032] The underlying problem is also solved by a vehicle with the portable reference sensor system according to one embodiment.

[0033] It is particularly preferred that the portable reference sensor system is rigidly connected to the vehicle via a connection system.

[0034] Due to the rigid connection, using the connection system, the portable reference sensor system can be arranged on the vehicle according to the requirements for avoiding movements.

[0035] According to a further embodiment, it can be particularly preferably provided that the connection system is rigidly connected to the vehicle on the one hand and rigidly connected to the portable reference sensor system on the other hand.

[0036] This can provide the rigid connection between the portable reference sensor system and the vehicle.

[0037] According to a further preferred embodiment, it can be provided that the portable reference sensor system is arranged at a distance from the vehicle by means of the connection system.

[0038] This allows air to flow past the reference sensor system and, consequently, past the base plate, especially during driving. This allows heat absorbed by the base plate to be dissipated, allowing the base plate to be cooled as well.

[0039] According to a further preferred embodiment, it can be provided that the reference sensor system is mounted on a vehicle after the calibration of the optical sensors and before the calibration of the position sensor.

[0040] According to a preferred embodiment, the portable reference sensor system can be mounted at least partially on a roof of the vehicle. The reference sensor system preferably comprises a roof box that can be mounted on any commercially available vehicle roof. In particular, the reference sensor system can be detachably connected to the vehicle, preferably plugged, screwed, clamped, suction-mounted, or the like. The necessary infrastructure, for example, for the power supply and data transfer, to operate the reference sensor system can preferably be accommodated in the trunk of the vehicle.

[0041] This has the advantage that the reference sensor system can be quickly converted from one vehicle to another. Furthermore, when positioned on the roof of the vehicle, the reference sensor system can generate a holistic 360° reference data set of the vehicle's surroundings.

[0042] The reference sensor system is preferably the AVL Dynamic Ground Truth (DGT) system.

[0043] According to a preferred embodiment, the portable reference sensor system comprises optical sensors and at least one position sensor or position system. Further preferably, the reference sensor system comprises at least one computing unit. The reference sensor system further preferably comprises a memory unit.

[0044] The optical sensors are preferably at least one selected from the group comprising lidar sensors, radar sensors, cameras, ultrasonic sensors, infrared sensors, and any combination thereof.

[0045] The position sensor can be a receiver of signals from a navigation satellite system.

[0046] Preferably, acquired sensor data of the reference sensor system can be processed by the computing unit and stored in the storage unit.

[0047] The detection range of all sensor units is preferably optimized for maximum coverage of the vehicle environment in 360° around the vehicle in order to ensure the usability of the reference data for as many Advanced Driver Assistance System (ADAS) functions as possible.

[0048] According to a preferred embodiment, the vehicle comprises a vehicle sensor system, wherein acquired sensor data of the vehicle sensor system can be compared with acquired environmental data of the reference sensor system of the vehicle's surroundings. The vehicle sensor system is preferably at least part of a driver assistance system (ADAS).

[0049] In particular, the vehicle sensor system is calibrated to the vehicle, allowing dynamic and static objects to be detected, classified, and positioned relative to the vehicle. In particular, the comparison of the sensor data is possible because the third position of the reference sensor system relative to the vehicle can be determined by the device, thus allowing dynamic and static objects to be detected, classified, and positioned relative to the vehicle.

[0050] All features disclosed in the application documents may be disclosed in a corresponding manner with appropriate wording for all claim categories.

[0051] Further objects, advantages and usefulness of the present invention are explained with reference to the accompanying drawings and the following description.

[0052] Here we show: Fig. 1 the basic requirements for the reference sensor system; Fig. 2 a reference sensor system; Fig. 3 a reference sensor system in a further representation; Fig. 4 a reference sensor system in a further representation.

[0053] In the figures, identical components are identified by the corresponding reference symbols. For clarity, some components may not be provided with a reference symbol in some figures, but are identified elsewhere.

[0054] The main application of a portable reference sensor system 1 is to generate an independent, highly accurate reference image of an environment during the development and validation phase of ADAS / AD sensors and systems, against which the system under test (SUT) or the vehicle sensors can be tested.

[0055] To make this possible, the data from the vehicle sensors and the reference sensor system sensors must be recorded synchronously in time and coordinated spatially in terms of the reference coordinate systems, a reference coordinate system 7 and a vehicle coordinate system 8.

[0056] An angular offset 13 of, for example, only 1° between the vehicle coordinate system 8 and the reference coordinate system 7 of the reference sensor system 1, leads trigonometrically to a lateral positioning deviation of the detected object of approximately 1.75 meters at a distance of 100 meters, as in the Fig. 1 can be seen.

[0057] Accordingly, a maximum angular offset 13 of 0.2° is defined as acceptable for the calibration of the reference sensor system 1, which corresponds to a positioning error of approximately 0.35 meters at a distance of 100 meters. Since the absolute translational calibration error does not scale with distance and a deviation of 0.05 meters can be achieved, this requirement is negligible.

[0058] In order to calibrate the reference coordinate system 8 and the vehicle coordinate system 9 to each other, it is first necessary to calibrate the reference sensor system 1.

[0059] In order not to alter the calibration, the invention provides that the portable reference sensor system 1 has a rigid base plate 9. The same applies to the connection between the base plate 9 and the vehicle 2, which should also be rigid.

[0060] The reference sensor system 1 comprises several optical sensors 3, which are designed as LIDAR sensors 5, 5' and cameras 4. Furthermore, a positioning system 6 with at least one position sensor 6 is shown. The LIDAR 5', also referred to as the central LIDAR 5', defines the reference coordinate system 7. The other LIDAR sensors 5 are referred to as lateral LIDAR sensors. This is, for example, the Fig. 2.

[0061] It can also be seen that the reference sensor system 1 has a housing element 11, which, in conjunction with the base plate 9, forms a housing 13. Openings 14 of the housing element 11 are also shown, through which the sensors 3, 4, 5 can extend.

[0062] In the Fig. 3 further shows that a housing element part 15 can be provided, which can be regarded as a detachable element of the housing element 11 and can be detachably connected thereto, for example by screw connections.

[0063] By removing the housing element part 15 it may be possible to reach the interior of the housing and accordingly the components arranged inside.

[0064] It can also be seen that the reference sensor system 1 is to be connected to the vehicle 2 by means of a connection system 16. The connection system 16 preferably comprises a first rail element 17 and a second rail element 18. The rail elements 17, 18 are preferably arranged spaced apart from one another, i.e., at a distance from one another. The rail elements 17, 18 are preferably spaced apart from one another in a width direction. The rail elements 17, 18 are preferably arranged extending in the longitudinal direction.

[0065] Preferably, a first cross rail 19 and a second cross rail 20 can also be provided, which are each connected, in particular rigidly connected, to the rail elements 17, 18. Likewise, it can be provided that the cross rails 19, 20 are connected, in particular rigidly connected, to the base plate 9.

[0066] In the Fig.4 shows the base plate 9 in more detail. The computing unit 10 is connected directly to the base plate 9, with the additional sensors 4, 5, 5' being indirectly connected to the base plate 9 via a respective holding element 21. The holding element 21 is connected to the sensor on one side and to the base plate 9 on the other, allowing the sensors to be arranged in their respective correct positions. Particularly preferably, the holding elements 21 are also thermally conductive, for example, made of the same thermally conductive material as the base plate or another suitable material, so that heat can be transferred from the sensors to the base plate 9 as a heat sink.

[0067] It is understood that the embodiments explained above represent only a first embodiment of the device according to the invention. Therefore, the embodiment of the invention is not limited to these embodiments.

[0068] All features disclosed in the application documents are claimed as essential to the invention, provided that they are new, individually or in combination, compared to the prior art. List of reference symbols 1 reference sensor system 2 vehicles 3 optical sensor 4 Camera 5 LIDAR 5' central LIDAR 6 Position system, position sensor 7 Reference coordinate system 8 Vehicle coordinate system 9 Base plate 10 computing unit 11 Housing element 12 housings 13 Angle, angular offset 14 Opening 15 Housing element part 16 Connection system 17 first rail element 18 second rail element 19 first cross rail 20 second cross rail 21 Holding element

Claims

[1] Portable reference sensor system with at least one optical sensor, at least one position sensor and a computing unit which is provided and designed to process sensor data of the at least one optical sensor and the at least one position sensor, characterized by that the portable reference sensor system has a rigid base plate, wherein the sensors and the computing unit are each connected directly or indirectly to the base plate. [2] Portable reference sensor system according to claim 1, characterized by that the base plate is made of a thermally conductive material and the sensors and / or the computing unit are thermally conductively connected to the base plate. [3] Portable reference sensor system according to claim 1 or 2, characterized bythat the reference sensor system has a housing element which is provided and designed to be connected to the base plate, whereby a housing is represented by the housing element and the base plate. [4] Portable reference sensor system according to claim 3, characterized by that the computing unit is arranged within the housing. [5] Portable reference sensor system according to claim 3 or 4, characterized by that the housing is sealed against liquid substances. [6] Portable reference sensor system according to one of claims 3 to 5, characterized by that the housing element has a plurality of openings through which the sensors can extend at least partially outwards. [7] Portable reference sensor system according to one of claims 3 to 6, characterized by that the housing element comprises a housing element part which is detachably connected to the housing element. [8] Vehicle with a portable reference sensor system according to one of claims 1 to 7. [9] Vehicle according to claim 8, characterized by that the portable reference sensor system is rigidly connected to the vehicle via a connection system. [10] Vehicle according to claim 9, characterized by that the connection system is rigidly connected to the vehicle on the one hand and to the portable reference sensor system on the other hand. [11] Vehicle according to claims 8 to 10, characterized by that the portable reference sensor system is arranged at a distance from the vehicle by means of the connection system.

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