Indoor Positioning Step Heading Correction via Wi-Fi Ranging
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Solution Overview
Problem
Traditional indoor positioning methods face inaccuracies and impracticalities, with Ultra-Wideband (UWB) technology lacking widespread adoption as anchor points, while Wi-Fi-based solutions are more prevalent but suffer from precision issues due to low accuracy in ranging measurements.
Innovation Solution
A method and device for estimating a moving object's position by correcting step information using reference position estimates, ranging measurements, and sensor readings, involving step size and heading corrections through damping filters and orientation adjustments, to enhance positioning accuracy in indoor environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If Wi-Fi based positioning is used for indoor positioning, then widespread availability and ease of operation are improved, but positioning accuracy deteriorates
Solution Approach 1:
The patent combines multiple positioning methods by merging Wi-Fi ranging measurements with step-and-heading information from inertial sensors. This hybrid approach leverages the widespread availability of Wi-Fi infrastructure while compensating for its accuracy limitations through sensor fusion, achieving both availability and improved positioning precision.
Solution Approach 2:
The positioning system uses a composite approach by integrating data from different sources (Wi-Fi ranging and inertial sensors) to create a more accurate positioning solution. The correction mechanism applies scale factors and heading adjustments derived from sensor data to the Wi-Fi based position estimates, forming a composite positioning result that overcomes the limitations of either method alone.
2Measurement precision
If UWB technology is used for indoor positioning, then positioning accuracy is improved, but device availability and ease of operation deteriorate
Solution Approach 1:
The patent uses readily available, low-cost Wi-Fi devices and inertial sensors as substitutes for expensive UWB infrastructure. Instead of requiring specialized UWB anchor points and devices, the system leverages ubiquitous Wi-Fi access points combined with standard motion sensors already present in mobile devices, achieving practical deployment feasibility.
Solution Approach 2:
The system replaces the need for specialized UWB hardware with a software-based correction mechanism that uses data from common inertial sensors (accelerometers, gyroscopes) to correct Wi-Fi positioning errors. This substitution of mechanical/specialized hardware with sensor-based computational correction enables widespread device availability while maintaining improved accuracy.
3Ease of operation
If step information is used for positioning estimation, then ease of operation is improved, but positioning accuracy deteriorates due to errors in step size and heading estimation
Solution Approach 1:
The patent implements a feedback mechanism where Wi-Fi ranging measurements provide position estimates that are used to correct step-and-heading information. The system calculates corrections to step sizes and headings based on the difference between expected and actual position changes, feeding these corrections back into the inertial navigation system to reduce accumulation errors and improve overall positioning accuracy.
Solution Approach 2:
The system performs preliminary correction of step-and-heading data by applying scale factors and heading adjustments derived from Wi-Fi position estimates before using the corrected information for positioning. This preliminary correction prevents error accumulation in the step-based positioning approach while maintaining its operational simplicity.
Data Source
AI summary
A method for estimating a position of a moving object comprises: storing one or more reference position estimates for the moving object in a first buffer; storing step information in a second buffer, the step information including one or more step sizes and one or more step headings; receiving a motion event signal indicating the moving object moves continuously with a bounded direction; correcting the step information based on the one or more reference position estimates in response to receiving the motion event signal; and estimating the position of the moving object using the corrected step information.