Vehicle UWB Localization Using IMU-Aided Probable Zone Narrowing
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Solution Overview
Problem
Existing methods for locating a user equipment with respect to a motor vehicle using ultra-wideband communication modules are limited by the need for multiple modules to be in communication simultaneously, which can be costly, energy-intensive, and prone to errors due to obstacles or satellite signal availability.
Innovation Solution
A method that uses ultra-wideband communication modules in conjunction with an inertial measurement unit in the user equipment to iteratively determine the location of the user equipment by exchanging ultra-wideband signals, measuring acceleration and orientation, and cross-referencing distances to narrow down probable location zones until a single accurate zone is determined.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of UWB communication modules is increased to improve location accuracy, then location precision is improved, but device cost, energy consumption, and wiring complexity increase significantly
Solution Approach 1:
The patent introduces an inertial measurement unit (IMU) as an intermediary device that measures user acceleration and orientation. This IMU data serves as a mediator between the limited UWB communication modules and the location determination system, enabling accurate location tracking with fewer modules by filling in the spatial information gaps through inertial sensing.
Solution Approach 2:
The patent changes the parameters used for location determination from relying solely on multiple UWB modules to combining UWB distance measurements with IMU-derived acceleration and orientation data. This parameter transformation allows the system to achieve the same location accuracy with fewer communication modules by utilizing different types of measurement data.
2Reliability
If multiple UWB communication modules are used to ensure continuous communication, then reliability is improved, but energy consumption increases
Solution Approach 1:
The IMU acts as a reliable intermediary that continuously tracks user motion and orientation independently of UWB communication availability. When UWB modules are not all actively communicating, the IMU data maintains location tracking reliability, reducing the need for all modules to remain continuously active and thus lowering energy consumption.
Solution Approach 2:
The patent uses partial action by activating only the minimum necessary number of UWB modules at any given time, supplemented by IMU data. Instead of requiring all modules to be simultaneously active for reliable location determination, the system uses a subset of modules combined with inertial measurement, achieving the same reliability with reduced energy expenditure.
3Device complexity
If signal strength-based triangulation is used to locate user equipment, then location determination is simplified, but measurement precision deteriorates due to signal attenuation
Solution Approach 1:
The patent replaces the purely electromagnetic signal strength-based location method with a hybrid approach that incorporates mechanical inertial measurement (accelerometer and gyroscope data from IMU). This substitution of mechanical sensing for electromagnetic sensing corrects the precision losses from signal attenuation while maintaining relatively simple system architecture.
Solution Approach 2:
The patent creates a composite location determination system that combines two different measurement technologies: UWB radio frequency distance measurement and IMU inertial measurement. This composite approach leverages the strengths of both methods (UWB for absolute distance, IMU for relative motion and orientation) to achieve higher overall precision than either method alone.
4Use of energy by moving object
If UWB communication modules communicate sequentially to reduce energy consumption, then energy efficiency is improved, but productivity deteriorates due to increased communication time
Solution Approach 1:
The patent applies partial action by using only a subset of UWB modules simultaneously for location determination, combined with IMU data. This allows the system to achieve accurate location tracking without requiring all modules to communicate sequentially, thus maintaining fast location determination speed while keeping energy consumption low through selective module activation.
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 method allows for accurate and quick location determination of the user equipment around the vehicle, reducing the number of required communication modules and overcoming limitations related to signal strength and satellite coverage.
Implementation Method 1
determining what is referred to as the 'inter-object' distance between said at least one ultra-wideband communication module of the vehicle and the user equipment based on the time of flight of the exchanged signals
Implementation Method 2
said user equipment, carried by a user, comprising an inertial measurement unit configured to provide acceleration and orientation data in relation to said user equipment
Data Source
AI summary
A method for locating a user equipment with respect to a motor vehicle, including the following steps, carried out iteratively when the user is in motion: determining what is referred to as the “inter-object” distance between an ultra-wideband communication module of the vehicle and the user equipment; computing what is referred to as the “inter-step” distance covered by the user between two consecutive steps based on the measured acceleration and orientation values; and cross-referencing the determined inter-object distance and the computed inter-step distance in order to determine at least one probable location zone of the user equipment. The iterations ending when a single probable location zone of the user equipment with a surface area smaller than a predefined surface area has been determined. The single probable location zone then corresponding to the location of the user equipment around the vehicle.