Modulated Mechanical Wave Localization for Mobile Devices
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Solution Overview
Problem
Existing methods for determining the location of a mobile device relative to a vehicle using low frequency waves are disruptive due to audibility issues, while high frequency waves can cause ambiguity in localization if microphone and speaker spacing is not adequate.
Innovation Solution
A method and system using a modulated mechanical wave with a high frequency carrier wave and a low frequency baseband signal, transmitted and received through speakers and microphones, to establish multiple localization paths for accurate determination of the mobile device's location, ensuring the signal is inaudible to humans and meeting spacing requirements for accurate localization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If low frequency waves are used for localization, then accurate location determination is achieved, but the waves become audible and disruptive to humans
Solution Approach 1:
The patent changes the frequency parameter of the carrier wave to be above the human audible range (greater than 20 kHz) while maintaining the use of mechanical waves for localization. This allows the system to achieve accurate localization through multiple path analysis while the carrier wave itself remains inaudible to humans, thus resolving the contradiction between measurement precision and harmful audibility effects
2Object-affected harmful factors
If high frequency waves are used for localization, then the waves are inaudible to humans, but ambiguity in location determination increases due to insufficient speaker/microphone spacing
Solution Approach 1:
The patent segments the signal into two distinct components: a high frequency carrier wave (inaudible) and a low frequency baseband signal (audible). The carrier wave provides the inaudible transmission medium, while the baseband signal contains the localization information. This segmentation allows the system to use high frequency waves without suffering from the ambiguity problem, because the baseband signal's lower frequency enables adequate spacing between speakers and microphones while the carrier wave remains inaudible
Solution Approach 2:
The patent introduces a baseband signal as an intermediary carrier of localization information. Instead of directly encoding position data into the high frequency carrier wave (which would cause ambiguity), the system uses the baseband signal as a mediator that can be properly spaced and resolved by the microphone array, while the carrier wave simply serves as the inaudible transmission medium
3Object-affected harmful factors
If high frequency carrier waves are used, then inaudibility is achieved, but the spacing requirements for accurate localization become more stringent
Solution Approach 1:
The patent segments the signal into carrier and baseband components with different frequency characteristics. The baseband signal operates at lower frequencies that satisfy the spacing requirements for accurate directional determination, while the carrier wave operates at high frequencies to ensure inaudibility. This segmentation decouples the spacing constraint from the inaudibility requirement, allowing the system to meet both goals simultaneously without increasing device complexity
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 solution provides accurate and non-disruptive localization of a mobile device relative to a vehicle, overcoming audibility issues and spacing constraints, while maintaining inaudibility to humans and ensuring precise determination of the device's location.
Implementation Method 1
causing the modulated signal to be transmitted from one or more speakers located on the mobile device or the vehicle; causing the modulated signal transmitted from the speaker(s) to be received at one or more microphones located on the other of the mobile device or the vehicle
Implementation Method 2
generating a modulated signal from a carrier wave and a baseband signal where the modulated signal is a mechanical wave, the carrier wave has an average carrier frequency and the baseband signal has an average baseband frequency that is less than the average carrier frequency; demodulating the modulated signal received at the microphone(s) for each of the plurality of localization paths
Data Source
AI summary
A system and method for locating a mobile device relative to a vehicle using mechanical waves and modulation techniques. A high frequency carrier wave that is generally inaudible to humans is modulated with a low frequency baseband signal that provides for accurate localization in order to generate a modulated signal. The modulated signal is a mechanical or pressure wave, as opposed to an electromagnetic (EM) wave, that is transmitted by one or more speaker(s) and is received by one or more microphone(s). In one example, the modulated signal is transmitted from a speaker on the mobile device (e.g., a smart phone) to a number of microphones mounted on the vehicle at specific distances apart, so as to establish multiple localization paths whose differences in phase can be used to determine the location of the mobile device, relative to the vehicle.