WLAN Positioning Speed Estimation Using Reference Databases
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current WLAN positioning systems are ineffective for wide-area deployments due to the inability to conduct detailed site surveys and maintain constant communication channels, and they struggle with accurately estimating speed and direction of travel due to shadowing and multi-path effects, especially in outdoor environments.
Innovation Solution
A method for estimating speed and direction of travel using WLAN access points involves receiving and analyzing signal strengths and characteristics from multiple access points, calculating average observation periods, and using reference databases to determine geographical locations, which enables continuous speed and bearing estimation even in changing environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detailed site surveys are conducted for every square foot of the campus to measure radio signal propagation, then positioning accuracy is improved to 1-3 meters, but device complexity and deployment cost increase significantly
Solution Approach 1:
The patent uses pre-collected reference signal strength data from site surveys as a digital map or reference database. Instead of performing actual physical site surveys during operation, the system copies and stores signal characteristics (RSSI values) from predetermined locations into a reference database, which is then used for positioning calculations during runtime.
Solution Approach 2:
The system performs site surveys and collects radio signal propagation data in advance during a setup phase, storing this information in a reference database. This preliminary action eliminates the need for real-time site surveys during actual positioning operations, significantly reducing deployment complexity while maintaining positioning accuracy.
2Reliability
If constant communication channels are maintained between access points and client radios for synchronization, then positioning reliability is improved, but loss of time for network connectivity requirements increases
Solution Approach 1:
The patent extracts the synchronization information from continuous network communication and places it into pre-collected reference data. By storing access point locations, signal strengths, and timing information in a reference database during setup, the system eliminates the need for constant network communication during positioning operations.
3Device complexity
If indoor positioning algorithms are used for outdoor wide-area deployment, then device complexity is reduced, but measurement precision deteriorates due to fundamentally different radio propagation characteristics
Solution Approach 1:
The patent applies different positioning algorithms suited for different environments. The system uses outdoor-appropriate algorithms that account for wide-area radio propagation characteristics when operating outdoors, while potentially using different algorithms for indoor environments. This local adaptation of algorithm quality to environmental conditions maintains positioning accuracy across different settings.
Data Source
AI summary
A method for estimating the speed and bearing of a Wi-Fi enabled device using WLAN radio signals in a WLAN based location service is provided. A method used to estimate a speed of travel of a Wi-Fi enabled device comprises the Wi-Fi enabled device receiving signals transmitted by Wi-Fi access points in range of the Wi-Fi enabled device, and using the signals to estimate the speed of and/or direction of travel of the Wi-Fi enabled device.