Obstacle Detection via Inertial and Time-of-Flight Distance Error
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Solution Overview
Problem
Current methods for optimizing Wi-Fi signal propagation in distributed networks, such as in dwellings, lack a simple and cost-effective way to detect and characterize obstacles like solid walls, which significantly impact signal coverage.
Innovation Solution
A method using a mobile terminal with inertial sensors and a reference equipment item, such as a residential gateway, to measure distance errors between time of flight and inertial measurements, detecting obstacles and determining their characteristics by analyzing the difference in distance measurements, particularly utilizing UWB signals to identify materials and thickness of walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional Wi-Fi signal mapping methods are used, then the system is simple to implement, but the measurement precision is insufficient due to inability to detect obstacles
Solution Approach 1:
The patent combines two different measurement systems (inertial measurement unit and time-of-flight measurement) into a single obstacle detection system. The IMU provides motion-based distance estimation while the time-of-flight system provides radio signal-based distance measurement, and their comparison enables obstacle detection without requiring additional specialized sensors
Solution Approach 2:
The patent uses the distance error between two measurement systems as an intermediary indicator to detect obstacles. Rather than directly detecting obstacles, the system measures the discrepancy between inertial-based distance and time-of-flight-based distance, where this error serves as the mediator that indicates obstacle presence and characteristics
2Measurement precision
If complex obstacle detection equipment is deployed, then the measurement precision improves, but the ease of manufacture and deployment deteriorates
Solution Approach 1:
The patent makes existing devices perform multiple functions: the mobile terminal's IMU (originally for motion tracking) and time-of-flight system (originally for distance measurement) are repurposed for obstacle detection and characterization. This eliminates the need for specialized obstacle detection equipment while maintaining measurement precision
Solution Approach 2:
The system uses the mobile terminal's own sensors (IMU and time-of-flight) to perform obstacle detection without requiring external specialized equipment. The device serves itself by utilizing its existing capabilities in a novel way to detect and characterize obstacles in the environment
3Reliability
If multiple measurement systems are integrated, then the reliability of obstacle detection improves, but the device complexity increases
Solution Approach 1:
The system uses feedback by continuously comparing the distance measurements from the IMU and time-of-flight system. The distance error serves as feedback that indicates whether an obstacle is present, and this feedback mechanism enables reliable obstacle detection through a simple comparison logic rather than complex integration
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 significantly improves the accuracy and efficiency of radio signal propagation mapping by effectively detecting and characterizing obstacles, enhancing network coverage without requiring complex or expensive equipment.
Implementation Method 1
each first distance measurement being obtained from at least one inertial measurement produced by at least one inertial sensor of the mobile terminal
Implementation Method 2
each second distance measurement being obtained from at least one time of flight measurement
Implementation Method 3
it uses the fact that, when a radio signal passes through a foreign environment, it is slowed down by the refraction phenomenon, such that the time of flight is extended
Data Source
AI summary
Obstacle detection and characterisation method, including the steps of: acquiring a first distance measurement obtained from at least one inertial measurement produced by at least one inertial sensor of a mobile terminal, and a second distance measurement obtained from at least one time of flight measurement; evaluating a distance error representative of a difference between the second distance measurement and the first distance measurement; from the distance error, detecting the presence of an obstacle between the mobile terminal and the reference equipment, and determining one or more characteristics of said obstacle.