Mobile Device Indoor Location via Sensor Space Mapping
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Solution Overview
Problem
Modern mobile devices face challenges in determining their location indoors with high accuracy and fine spatial resolution, as they primarily rely on GPS coordinates, which are limited and require a connection to GPS satellites, and manual input of floor plans, which can be cumbersome.
Innovation Solution
The use of sensor measurements from stationary sources like Wi-Fi routers to create a sensor space mapping, allowing mobile devices to determine their physical location without explicit coordinates by clustering sensor positions and applying kernel functions to calculate probabilities based on physical distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS coordinates are used to determine location, then location determination is possible, but measurement precision and spatial resolution are limited
Solution Approach 1:
The patent segments the location determination problem into two parts: coarse location via GPS and fine-grained indoor location via sensor space mapping. By dividing the positioning task across different measurement systems, the patent achieves both broad coverage and high precision without relying solely on GPS limitations.
Solution Approach 2:
The patent introduces sensor measurements (Wi-Fi signal strength, Bluetooth signals, accelerometer data) as intermediary variables that bridge the gap between GPS coordinates and actual physical position. These sensors act as mediators that provide continuous location feedback even when GPS is unavailable or imprecise indoors.
2Measurement precision
If manual input of floor plans is required, then location determination can be performed, but ease of operation deteriorates
Solution Approach 1:
The patent enables the system to automatically create and update its own location mapping by having users simply walk through the space while the mobile device collects sensor data. The system self-configures by clustering sensor measurements to identify physical locations without requiring manual floor plan input or surveying expertise.
Solution Approach 2:
The patent performs preliminary location mapping during an initial setup phase where sensor data is collected and clustered to create the sensor-to-physical space mapping. This preliminary action establishes the location framework in advance, so that subsequent location determinations can be performed automatically without repeated manual configuration.
3Measurement precision
If sensor space mapping is implemented, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent makes existing mobile device sensors (accelerometer, Wi-Fi, Bluetooth) serve multiple functions: they provide both motion tracking data and location identification data. By extracting location information from sensor clusters, the system achieves high precision without adding dedicated positioning hardware, thus managing complexity while improving measurement capability.
Data Source
AI summary
A mobile device can identify its physical location without explicit knowledge of physical coordinates, but instead using sensor measurements dependence on distance, e.g., signal strength from a Wi-Fi router. Sensor measurements can be used to determine the mobile device is at a same physical location as a previous measurement. For example, numerous measurements of sensor values can form data points that are clustered in sensor space, where a cluster of data points in sensor space corresponds to a physical cluster of physical positions in physical space. A current physical location of the mobile device can be determined by identifying which cluster of sensor positions the current measurements correspond. To identify the cluster of sensor positions, a probability can be determined for each cluster based on a sensor distance between the current measurement and a representative data point of the cluster and a kernel function.