Wireless Device Distance Estimation Using Power Feedback
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Solution Overview
Problem
Existing methods for determining the location of a mobile device indoors using wireless signals are inaccurate due to reliance on GPS, which fails without additional infrastructure, and require complex communication setups or fixed device spacing, while existing localization systems using Bluetooth signals struggle to accurately correlate signal strength with distance.
Innovation Solution
An apparatus and method that involves a primary device transmitting a signal to a secondary device, adjusting transmission power based on a link quality indicator, and using a filtered transmission power level to determine the distance between the devices, employing an extended Kalman filter to recursively update and refine the distance estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS technology is used for determining location, then location can be determined, but it does not work well indoors without additional infrastructure
Solution Approach 1:
The patent replaces GPS satellite-based electromagnetic positioning with a local wireless communication-based positioning system using Bluetooth signals and signal strength measurement, eliminating the need for satellite infrastructure and making indoor localization feasible
Solution Approach 2:
The patent introduces intermediate devices (access points or wireless devices) that act as mediators between the mobile device and the positioning system, enabling indirect location determination through signal strength measurement and triangulation/trilateration methods
2Measurement precision
If triangulation or trilateration methods are used, then location can be determined, but communication between more than two devices and fixed spacing is required
Solution Approach 1:
The patent makes the positioning system universal by allowing flexible device configurations - it can work with two devices, multiple devices, or varying spacing arrangements, eliminating the rigid requirements of traditional triangulation methods while maintaining positioning accuracy
Solution Approach 2:
The patent changes the approach from fixed geometric parameters (fixed spacing, specific device arrangements) to flexible signal-based parameters (signal strength, transmission power levels), allowing dynamic adaptation to different device configurations and spacing
3Measurement precision
If existing Bluetooth localization systems are used, then distance can be estimated, but accurate correlation between signal strength and distance is difficult
Solution Approach 1:
The patent implements feedback mechanisms where devices exchange signal strength information and adjust transmission power levels based on received signal quality, enabling iterative refinement of distance measurements and improving accuracy through continuous optimization
Solution Approach 2:
The patent introduces dynamic adjustment of transmission power levels based on real-time signal conditions and distance estimates, allowing the system to adapt to changing environmental factors and maintain accurate positioning across varying conditions
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
Enables accurate determination of distance between wireless devices, allowing for precise location tracking and automatic activation/deactivation of media devices, improving indoor localization without the need for additional infrastructure or complex setups.
Implementation Method 1
transmit a signal at a transmission power level to a secondary device
Implementation Method 2
employing an extended Kalman filter to recursively update and refine the distance estimation
Data Source
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AI summary
An apparatus for mobile device localization is provided with a primary device. The primary device is configured to transmit a first signal at a first transmission power level to a secondary device and to receive a response signal that is indicative of a quality indicator of the first signal as received by the secondary device. The primary device is further configured to determine a second transmission power level based on the quality indicator; transmit a second signal at the second transmission power level to the secondary device; and to determine a distance between the primary device and the secondary device based on a filtered transmission power level value.