Proximity-Sensor Dead Reckoning for Indoor Mobile Positioning
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Solution Overview
Problem
Existing location determining techniques, such as GPS and cellular signal triangulation, are unreliable when a mobile device is within a building due to signal interference, leading to inaccuracies in determining the device's position using dead reckoning, which varies based on its proximity to the user.
Innovation Solution
A method and apparatus using a plurality of proximity sensors to determine the mobile device's position relative to the user, adjusting the duration of dead reckoning based on its proximity, and employing acceleration data from an accelerometer to track the device's location, with capacitive proximity sensors detecting human body presence through capacitance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dead reckoning is used to determine location when GPS signals are unavailable, then location determination is possible within buildings, but inaccuracy increases over time and distance
Solution Approach 1:
The patent dynamically adjusts the dead reckoning tracking duration based on device proximity to the user. When the device is close to the user (detected via proximity sensors), the system extends the tracking period and allows greater displacement. When the device moves away, the system shortens or stops tracking. This dynamic adaptation resolves the contradiction by making accuracy contingent on real-time spatial relationship rather than fixed time/distance limits.
Solution Approach 2:
The system continuously monitors proximity sensor data to determine device-user spatial relationship and uses this feedback to adjust dead reckoning parameters. The proximity information feeds back into the location determination algorithm, allowing the system to maintain higher accuracy when the device is near the user and gracefully degrade or stop when distance increases, thus resolving the accuracy-time contradiction.
2Loss of information
If dead reckoning tracks location for extended periods, then more location data is collected, but power consumption increases
Solution Approach 1:
The patent implements dynamic power management by adjusting dead reckoning operation based on proximity sensor feedback. When the device is detected near the user, the system maintains continuous location tracking with higher power consumption. When the device moves away, the system reduces or stops tracking to conserve power. This dynamic approach resolves the contradiction between tracking continuity and power consumption by making resource usage contingent on actual need.
Solution Approach 2:
The system uses the mobile device's own proximity sensors to determine when location tracking should continue or stop, eliminating the need for external control signals. The device self-regulates its power consumption based on its spatial relationship with the user, resolving the contradiction autonomously without requiring additional power-intensive external coordination.
3Duration of action of stationary object
If dead reckoning is used when the device is remote from the user, then location tracking is maintained, but inaccuracy significantly increases
Solution Approach 1:
The patent introduces proximity sensor data as an intermediary condition that mediates between tracking duration and accuracy. Rather than allowing unlimited tracking regardless of device position, the proximity information acts as a gatekeeper that enables or disables extended tracking based on device-user distance. This intermediary mechanism resolves the contradiction by ensuring extended tracking only occurs when spatial conditions support acceptable accuracy.
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 reduces inaccuracy in dead reckoning by limiting tracking time and distance based on the device's position, conserving power and improving location determination accuracy within buildings where traditional methods fail.
Implementation Method 1
capacitive proximity sensors detecting human body presence through capacitance changes
Data Source
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AI summary
Various arrangements for limiting inaccuracy of dead reckoning are presented. Proximity data may be collected using a plurality of proximity sensors of a mobile device. A position of the mobile device may be determined in relation to a user using the proximity data. Whether to determine a location of the mobile device using a dead reckoning technique may be determined at least partially based on the position of the mobile device in relation to the user.