Ultrasonic Sensor Signal Association via Elementary Pulse Sequences
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Solution Overview
Problem
Existing ultrasonic sensor systems for motor vehicles face challenges in accurately associating reflected ultrasonic signals with the emitted signals due to overlapping signal emissions and the resulting 'blind zone' near the sensor, which limits minimum measuring distance and scanning rate.
Innovation Solution
The method involves emitting ultrasonic signals composed of sequences of elementary signals with signal pauses and multiple different signal pulses, allowing for distinct identification and association of reflected signals based on their sequences, utilizing pulse-pause coding and orthogonal signal pulses like positive and negative chirps, Barker codes, or Gold codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple ultrasonic sensors emit signals simultaneously, then object detection coverage is improved, but signal association between emitted and reflected signals becomes difficult
Solution Approach 1:
The ultrasonic signal is segmented into multiple elementary signals with distinct characteristics (different frequencies, phases, or amplitudes). Each sensor emits a unique sequence of these elementary signals, allowing the receiver to identify and associate reflected signals with their respective source sensors through pattern recognition, even when multiple sensors operate simultaneously.
Solution Approach 2:
The system changes parameters of the ultrasonic signals (frequency, phase, amplitude, or time intervals between elementary signals) to create distinguishable signal patterns for each sensor. This parameter variation enables the receiver to differentiate between signals from different sensors and correctly associate reflected signals with their source, resolving the signal association problem while maintaining multi-sensor operation.
2Use of energy by moving object
If pulse duration is extended, then signal energy is improved, but blind zone distance increases
Solution Approach 1:
Instead of using a single long pulse, the signal is divided into multiple short elementary signals separated by time intervals. This segmentation maintains short individual pulse durations (reducing blind zone) while accumulating sufficient energy through the sequence of multiple pulses. The receiver can detect reflected signals from each elementary signal, improving overall signal energy without extending the blind zone.
Solution Approach 2:
The system uses periodic emission of elementary signals with specific time intervals between them. This periodic structure allows the sensor to emit multiple pulses over an extended period, accumulating energy while maintaining short individual pulse widths. The time intervals are optimized to allow echo reception between pulses, preventing blind zone extension while ensuring sufficient total energy for detection.
3Loss of information
If temporal distance between consecutive signals is increased, then signal association is improved, but scanning rate decreases
Solution Approach 1:
The signal sequence is segmented into multiple elementary signals that can be emitted in rapid succession with distinct characteristics. Each elementary signal acts as an independent identifier, allowing the receiver to associate reflected signals with their source even when the overall scanning cycle is accelerated. This segmentation enables higher scanning rates without sacrificing association accuracy.
Solution Approach 2:
The system uses parameter variations (frequency, phase, amplitude) across elementary signals to enable rapid emission cycles. By encoding sensor identity information into these parameters, the system can emit signals at high rates while the receiver accurately identifies the source of each reflected signal through parameter matching, maintaining association accuracy despite reduced temporal distances between emissions.
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 ability to clearly associate received ultrasonic signals with their corresponding sensors, reducing the 'blind zone' and enabling more accurate and efficient object localization, thereby improving parking and automated driving capabilities.
Implementation Method 1
Ultrasonic sensors have a transmitting device which emits ultrasonic signals which propagate in air at the speed of sound of roughly 340 meters per second
Implementation Method 2
The ultrasonic signal is reflected by objects in the surroundings and is detected by a receiver device of the ultrasonic sensor
Data Source
AI summary
The invention relates to a method for operating ultrasonic sensors) for a motor vehicle, including emitting a plurality of ultrasonic signals by respective ultrasonic sensors. The ultrasonic signals include a sequence of elementary signals. The elementary signals have signal pauses and a plurality of different signal pulses. The ultrasonic signals differ from one another by the sequence of the elementary signals. The method further includes receiving reflected ultrasonic signals, wherein the received ultrasonic signals are associated with the emitted ultrasonic signals on the basis of the sequences of the elementary signals.