Extending Indoor Radio Map Boundaries Using Harvested Trajectories
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Solution Overview
Problem
Conventional GPS-based location determination in mobile devices is prone to errors in areas with obstructed line of sight, such as indoors or in tunnels, and fails to accurately determine floor, room, or street level locations due to large error margins.
Innovation Solution
A method and system that extend a radio map of an indoor venue by using survey data and harvest data from mobile devices positioned outside the initial map boundary, determining trajectories, and identifying new locations to expand the map's boundary, incorporating RSSI measurements and sensor data to improve location accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS signals are used for location determination, then outdoor location can be determined, but location accuracy deteriorates in areas with obstructed line of sight such as indoors or tunnels
Solution Approach 1:
The patent introduces an intermediary positioning system using Wi-Fi access points and radio maps as mediators between GPS satellites and mobile devices in GPS-denied environments. The system uses Wi-Fi signals from access points as intermediate carriers to determine location when direct GPS satellite signals are blocked, thereby maintaining reliability while improving accuracy in indoor and tunnel environments
Solution Approach 2:
The patent replaces the GPS satellite-based electromagnetic signal system with a Wi-Fi-based radio map system for indoor positioning. By substituting the GPS mechanical/electromagnetic system with a Wi-Fi infrastructure system, the patent enables location determination in environments where GPS signals cannot penetrate, thus improving both reliability and accuracy in covered areas
2Area of stationary object
If radio map boundary is extended to include unsurveyed areas, then location coverage is improved, but measurement precision may deteriorate in extended areas without survey data
Solution Approach 1:
The patent applies preliminary action by pre-collecting Wi-Fi survey data in accessible areas and pre-computing radio maps before actual positioning needs arise. This allows the system to have location determination capability ready in advance for areas that will later be visited by mobile devices, improving coverage without compromising accuracy through proper survey-based data collection
Solution Approach 2:
The patent implements feedback mechanisms where harvest data from mobile devices in unsurveyed areas is collected and used to refine and update the radio map. This feedback loop allows the system to progressively improve measurement precision in extended areas by incorporating actual observed data from mobile devices back into the positioning system
Data Source
AI summary
A method comprising: receiving a radio map of an indoor venue using survey data collected by a survey device positioned throughout the venue, the radio map including a boundary; receiving harvest data from a mobile device, wherein at least some of the harvest data are obtained by the mobile device while the mobile device is positioned at locations that are outside of the boundary; determining, based on the harvest data, a trajectory of the mobile device, wherein at least some of the trajectory resides outside of the boundary; identifying one or more locations on or proximate to the trajectory; and extending the radio map using the survey data and the one or more identified locations, wherein the extended radio map is defined at least in part by an extension of the boundary to encompass the one or more identified locations.