Vehicle Sensor Misalignment Detection Using Stationary Reference Objects
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Solution Overview
Problem
Existing methods for aligning vehicle sensors, such as radar sensors, are limited in recalibrating sensors not aligned parallel to the vehicle's direction of travel, particularly those installed at angles between 0° and 90°, and require additional equipment like video sensors, making real-time misalignment detection and recalibration challenging.
Innovation Solution
A method using stationary targets like guardrails or parked vehicles to estimate misalignment by measuring the deviation between predicted and actual reflection positions, allowing for rapid and precise recalibration of sensors with diagonally aligned main beam directions, and utilizing overlapping detection areas for cross-validation of misalignment angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If video sensors are used to align radar sensors, then alignment precision is improved, but device complexity increases and additional equipment is required
Solution Approach 1:
The patent uses stationary objects (guardrails, walls, parked vehicles) as intermediary reference objects to establish a coordinate system for alignment. Instead of directly comparing radar and video sensor data, the system uses these environmental features as a common reference frame that both sensors can detect and align to, eliminating the need for one sensor to calibrate the other.
Solution Approach 2:
The radar sensor aligns itself using stationary environmental objects as references. The system autonomously determines its own alignment parameters by detecting objects like guardrails and comparing their positions across multiple measurements, without requiring external calibration equipment or additional sensor types.
2Ease of operation
If sensors are aligned parallel to direction of travel, then alignment determination is simplified, but adaptability to diagonal installations (0-90 degrees) is reduced
Solution Approach 1:
The alignment method works universally for sensors installed at any angle (0-90 degrees) relative to the direction of travel. By using stationary environmental objects as reference points and establishing a coordinate system based on these objects, the system can determine alignment parameters regardless of the sensor's installation orientation, making the method applicable to front, side, and corner-mounted sensors.
Solution Approach 2:
The patent transitions from one-dimensional alignment (parallel to direction of travel) to two-dimensional alignment by incorporating angular measurements and coordinate transformations. The system uses azimuth angles and object positions in multiple directions to calculate alignment parameters for sensors at various orientations, adding angular dimensionality to the alignment process.
3Loss of time
If misalignment is ascertained over short periods, then time consumption is reduced, but measurement precision deteriorates due to insufficient data
Solution Approach 1:
The system performs preliminary actions by continuously tracking and storing object positions and alignment parameters over time. Before a formal misalignment assessment is needed, the system has already accumulated measurement data from ongoing operations, allowing it to quickly compute accurate misalignment values without requiring a separate, time-consuming calibration process.
Solution Approach 2:
The alignment determination is performed continuously as the vehicle operates, using ongoing detection of stationary objects to maintain up-to-date alignment parameters. This continuous measurement approach ensures that sufficient data is always available for precise misalignment assessment without requiring the vehicle to stop or enter a dedicated calibration mode.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable and rapid estimation of misalignment angles for sensors installed at various angles, ensuring accurate recalibration and preventing system shutdown due to misalignment, even in cases of minor accidents, by averaging misalignment over longer periods for reliable calibration.
Implementation Method 1
at least one detection unit (2) which emits signals and receives partial signals (7) which have been reflected on objects
Implementation Method 2
receives partial signals (7) which have been reflected on objects
Data Source
AI summary
A method and a device for ascertaining a misalignment of at least one detection unit fastened on a vehicle with respect to the intended sensor main beam direction. The device includes at least one detection unit which emits signals and receives partial signals which have been reflected on objects, and ascertains the distance and the azimuth angle of the reflecting objects, and further includes an evaluation unit, to which the ascertained positions of the at least one detection unit are forwarded, and the determination of a misalignment takes place in the evaluation unit by comparing the stored alignment of the sensor main beam direction and the ascertained angle of the object extension with respect to the sensor main beam direction, this taking place under the assumption that the vehicle is moving on average, in parallel to the object extension, for the period during which the misalignment is ascertained.