Ultrasound Sensor Offset Angle Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ultrasound sensors in driver assistance systems for motor vehicles can only determine the distance of an object but not its relative offset angle, which is crucial for systems like parking space measurement and automatic parking.
Innovation Solution
A method and device using frequency-modulated ultrasound pulses to determine the relative offset angle by analyzing the frequency spectrum of echo pulses, allowing for absolute angle calculation based on directional characteristics, and employing triangulation with multiple measurements to obtain a signed offset angle, while compensating for the Doppler Effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ultrasound sensors are used to measure distance, then the distance measurement function is achieved, but the relative offset angle information is lost
Solution Approach 1:
The patent changes the transmission frequency parameter of the ultrasound sensor to vary its directional characteristic. By transmitting ultrasound pulses at multiple predefined frequencies, the sensor's beam pattern changes, causing the amplitude of the echo pulse to vary characteristically with the object's angular position. This frequency-based parameter change enables the system to extract angular position information from the frequency spectrum of the echo pulse while maintaining distance measurement capability.
2Measurement precision
If frequency-modulated ultrasound pulses with multiple transmission frequencies are used, then the relative offset angle can be determined, but the device complexity increases
Solution Approach 1:
The patent uses the frequency spectrum of the echo pulse as an intermediary to transfer angular position information. Instead of directly measuring angle with a complex sensor array, the system modulates the ultrasound frequency and uses the frequency-dependent directional characteristic to encode angular information into the echo's frequency spectrum. The evaluation unit then decodes this information by analyzing spectral characteristics, effectively using frequency analysis as an intermediary mechanism.
3Device complexity
If a single ultrasound sensor is used for position determination, then the device structure is simplified, but the measurement reliability is reduced due to ambiguities
Solution Approach 1:
The patent employs periodic frequency modulation of the ultrasound transmission, using multiple predefined frequencies in a systematic sequence. This periodic variation of transmission frequencies creates distinct, repeatable patterns in the echo frequency spectrum that are characteristic of different angular positions. By using this periodic frequency sweep approach, the single sensor can reliably distinguish between different objects and angular positions without the ambiguities that would otherwise require multiple sensors.
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
This approach enhances the accuracy and reliability of position determination for objects relative to a vehicle, avoiding ambiguities and improving the quality of driver assistance systems by determining absolute and signed offset angles with a single ultrasound sensor.
Implementation Method 1
compensating for the Doppler Effect
Data Source
AI summary
In a method and a device for determining the position of an object in relation to a vehicle, for use in a driver assistance system of the vehicle, a first ultrasound pulse is transmitted by an ultrasound sensor situated on the vehicle, the ultrasound pulse including multiple predefined transmission frequencies which result in a variation of the directional characteristic of the ultrasound sensor. The transmitted first ultrasound pulse is reflected on the object and is received again as a first echo pulse. A frequency spectrum of the first echo pulse is subsequently determined, and a first absolute value of a relative offset angle of the object is determined as a function of the frequency spectrum of the first echo pulse and the directional characteristics.