WiFi FTM Self-Calibration for Enterprise Indoor Localization
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Solution Overview
Problem
Existing WiFi Fine Time Measurement (FTM) protocols face challenges in delivering accurate localization due to significant range offsets and errors when interacting with heterogeneous devices and varying environmental conditions, making them unsuitable for enterprise-scale applications.
Innovation Solution
An over-the-top auto-calibration solution, WiLoc, allows WiFi devices to self-calibrate range offsets by leveraging user mobility and onboard sensors to measure ranges at different points on a trajectory, using linear or quadratic solvers to compensate for unknown offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If WiFi FTM ranging protocol is used for localization, then device omnipresence and coverage area are improved, but range offset accuracy deteriorates
Solution Approach 1:
The system changes the operational parameters by having the mobile device move to multiple locations and measure ranges at each point. By collecting range measurements at different positions along a trajectory and using these varying parameters to solve for the offset through mathematical computation, the system achieves accurate calibration despite the inherent inaccuracy of WiFi FTM ranging protocol.
Solution Approach 2:
The system uses feedback from multiple range measurements taken at different locations to continuously refine and determine the range offset. The mobile device collects range data from multiple access points at various positions, processes this feedback information through computational algorithms, and uses the results to self-calibrate the offset, thereby improving measurement accuracy.
2Measurement precision
If range offset calibration is performed manually, then measurement accuracy is improved, but device complexity and operational effort increase
Solution Approach 1:
The mobile device performs self-service by automatically calibrating its own range offset without requiring manual intervention or external calibration equipment. The device uses its own motion (tracked via onboard sensors) and range measurements to compute and apply the necessary offset correction, thereby simplifying the overall system while maintaining high measurement accuracy.
Solution Approach 2:
The system introduces an intermediary computational process that automatically processes range measurements and trajectory data to determine the offset. This intermediary algorithm acts as a mediator between the raw measurements and the final calibrated results, eliminating the need for complex manual calibration procedures while achieving accurate offset compensation.
3Measurement precision
If multiple range measurements are taken at different locations, then offset prediction accuracy is improved, but measurement time and processing complexity increase
Solution Approach 1:
The system applies partial action by requiring only a limited number of range measurements at a few key locations along the trajectory rather than exhaustive measurements at every possible point. This partial sampling is sufficient to accurately determine the offset through mathematical computation, thereby reducing the time and processing effort required while maintaining high prediction accuracy.
Data Source
AI summary
A method for assessing viability of a WiFi fine tune measurement (FTM) based ranging protocol for enterprise-grade localization with heterogeneity across operational parameters is presented. The method includes enabling a plurality of access points to range with a plurality mobile devices handled by a plurality of users within an enterprise environment, tracking a mobile device of the plurality of mobile devices using onboard sensors as the mobile device travels within the enterprise environment, measuring a plurality of ranges with at least three access points of the plurality of access points at various points along a trajectory, and combining information related to the plurality of ranges and the trajectory to predict a range offset of the mobile device such that the mobile device itself self-calibrates all its range offsets on-demand.