Ultrasonic Echo Filtering for Accurate Parking Space Detection

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Solution Overview

Problem

Existing parking space detection methods using ultrasonic sensors are computationally intensive and prone to errors due to inaccuracies in the odometry system and noise, leading to unreliable results.

Innovation Solution

A method and system that utilize ultrasonic sensors to create a detection list with location and neighborhood indicators, filter echoes based on neighborhood relationships, and determine azimuth angles to accurately detect parking spaces with reduced computational and memory requirements, minimizing false positives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If trilateration is used to determine spatial direction and distance, then parking space detection capability is improved, but computational complexity and processing time increase significantly

Engineering Contradiction:
Improveparking space detection accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the continuous detection space into discrete grid cells with specific resolutions. Each grid cell independently stores detection results, transforming the complex continuous space problem into multiple simple discrete cell problems. This segmentation reduces computational complexity while maintaining detection accuracy through systematic grid-based processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent pre-establishes a grid structure covering the entire detection area before actual detection begins. Grid cells are pre-configured with resolution parameters and storage structures, allowing immediate detection without dynamic computation during operation. This preliminary setup eliminates complex real-time spatial calculations.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If multiple ultrasonic sensors are used to improve detection coverage, then measurement reliability is improved, but false positive rate increases due to noise accumulation

Engineering Contradiction:
Improvedetection reliabilityVSAvoidfalse positive rate
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent merges detection results from multiple ultrasonic sensors into a unified grid-based detection list. All sensor data are integrated into the same grid structure, allowing consistent processing and noise filtering across the entire detection area. This unified approach reduces false positives by eliminating redundant detections through grid cell consolidation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The grid structure serves as an intermediary between multiple sensors and the final detection results. Each grid cell acts as a mediator that aggregates signals from multiple sensors, applying noise filtering and thresholding at the grid level before producing final parking space detection. This intermediary processing significantly reduces false positives while maintaining detection reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If detailed odometry information is used to track vehicle position, then detection precision is improved, but computational load and memory requirements increase

Engineering Contradiction:
Improveposition detection precisionVSAvoidmemory requirements
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies local quality by using a resolution parameter that can vary across different grid cells. Areas requiring higher precision (such as near the vehicle) use finer grid resolution, while distant areas use coarser resolution. This local adaptation reduces overall memory requirements while maintaining necessary precision in critical detection zones.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the resolution parameter dynamically based on detection needs and vehicle position. The grid resolution can be adjusted according to the vehicle's movement state and detection requirements, optimizing the balance between precision and memory usage. This parameter adaptation allows the system to maintain high precision when needed while reducing computational load during normal operation.

Inventive Principle:
Principle #35Parameter changes

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

The method enables efficient and accurate detection of available parking spaces by filtering out noise and reducing computational load, ensuring reliable parking space detection with minimal false positives.

Implementation Method 1

a detection list is created in a storage unit, wherein the detection list for received reflected signal components of ultrasonic signals (hereinafter also referred to as echo or ultrasonic echo)

Methodology Applied
Scientific EffectUltrasonic echo: Echo

Implementation Method 2

An ultrasonic signal is emitted by an ultrasonic sensor on the vehicle

Methodology Applied
Scientific EffectUltrasonic signal transmission: Ultrasound

Implementation Method 3

The azimuth angle is determined based on the radial velocity of the vehicle relative to an object at which the reflection occurs

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP4256377B1Method for identifying parking spaces by means of ultrasonic sensors
Publication Date: 2025.09.10 CONTINENTAL AUTONOMOUS MOBILITY GERMANY GMBH
  • EP4256377B1 patent drawingFigure 1
  • EP4256377B1 patent drawingFigure 2~3
  • EP4256377B1 patent drawingFigure 4

AI summary

The invention relates to a method for identifying parking spaces by means of at least one ultrasonic sensor of a vehicle.