Mobile Station Position Estimation Using Base Station Almanac
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Solution Overview
Problem
Current position estimation methods for mobile stations, such as cellular telephones, face challenges in achieving accurate and efficient location determination, particularly in environments with limited satellite coverage, like buildings, where satellite signals are unavailable.
Innovation Solution
Mobile stations utilize a combination of signals from terrestrial base stations and sensors to perform dead reckoning navigation and update a base station almanac with estimated access point locations, enhancing position fix accuracy and sharing this information with other stations to improve network-wide position estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If satellite positioning signals are used for position estimation, then position accuracy is improved, but position estimation fails in environments with limited satellite coverage such as buildings
Solution Approach 1:
The system segments the positioning function into multiple independent components: satellite positioning component and terrestrial base station component. Each component operates independently and can be selected based on environmental conditions, allowing the system to maintain positioning capability both outdoors with satellite coverage and indoors with limited satellite coverage.
Solution Approach 2:
The mobile station is designed with multi-functionality to perform both satellite-based positioning and terrestrial base station-based positioning. The device can automatically switch between positioning methods depending on signal availability, ensuring universal positioning capability across different environments including buildings and open areas.
2Adaptability or versatility
If terrestrial base station signals are used for position estimation, then position estimation works in satellite-deprived areas, but position accuracy deteriorates compared to satellite signals
Solution Approach 1:
The system implements feedback mechanisms where the mobile station continuously monitors signal availability and positioning quality from both satellite and terrestrial sources. Based on this feedback, the device dynamically selects and switches between positioning methods, and the network server receives positioning results to maintain and update the base station almanac with accurate location information.
Solution Approach 2:
The positioning system uses a composite approach by combining satellite positioning data and terrestrial base station positioning data. The mobile station can fuse information from multiple sources to achieve accurate positioning, leveraging the strengths of both methods: satellite signals for high accuracy in open areas and terrestrial signals for coverage in satellite-deprived areas.
3Loss of time
If mobile stations independently perform position estimation, then position fixes are obtained quickly, but network-wide position estimation efficiency decreases
Solution Approach 1:
The network server performs preliminary actions by maintaining a pre-computed base station almanac containing location information of multiple base stations. This almanac is prepared in advance and distributed to mobile stations, enabling devices to quickly perform position estimation without needing to query the network for each positioning request, thus reducing position fix time while maintaining network efficiency.
Solution Approach 2:
The base station almanac acts as an intermediary between the network and mobile stations. It pre-contains location information of multiple base stations, allowing mobile stations to independently perform position estimation using stored data without continuous network communication. This intermediary structure enables fast local positioning while the network maintains overall efficiency by avoiding repeated data transmissions.
Data Source
AI summary
The subject matter disclosed herein relates to providing assistance information to a mobile station for performing position estimation operations.