Satellite Selection Using Cached Ephemeris Data
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Solution Overview
Problem
Current radio communication systems, particularly GPS-based systems, face limitations in mobile device location determination accuracy and efficiency due to high computational loads and long acquisition times, which can deplete battery power and fail to meet stringent FCC requirements for E-911 services.
Innovation Solution
A method and system for optimizing satellite selection in view by using cached satellite information and assistance data to reduce computational load and improve acquisition efficiency, allowing for faster and more accurate location determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS satellite signals are acquired and processed to determine mobile device location, then location accuracy is improved, but acquisition time increases and battery power is depleted
Solution Approach 1:
The system performs preliminary actions by pre-calculating and storing satellite ephemeris data, almanac data, and satellite visibility information in cached formats before they are needed for actual location determination. This allows the GPS receiver to quickly acquire satellite signals and compute position without performing lengthy calculations from scratch, thereby reducing acquisition time while maintaining location accuracy
2Measurement precision
If GPS satellite signals are acquired and processed to determine mobile device location, then location accuracy is improved, but energy consumption increases
Solution Approach 1:
The system pre-computes satellite ephemeris, almanac, and visibility data and caches them in optimized formats, reducing the computational burden during actual GPS acquisition. This preliminary preparation significantly lowers the energy required by the mobile device's GPS receiver to determine location while preserving measurement precision
Solution Approach 2:
The system introduces an intermediary component (cached satellite data and assistance information) that mediates between the satellite signals and the location computation process. This intermediary provides pre-processed information that reduces the computational complexity and energy consumption of the final location determination while maintaining accuracy
3Measurement precision
If conventional GPS processing is used to determine location, then location determination is achieved, but computational load is excessive for mobile devices
Solution Approach 1:
The system performs complex satellite ephemeris calculation, almanac generation, and satellite visibility analysis in advance and stores the results in cached, optimized data structures. This preliminary computation reduces the real-time processing requirements for mobile devices, lowering computational load while maintaining location determination capability
Solution Approach 2:
The system creates simplified copies of satellite orbital and positional information in cached formats that approximate full precision data but require less computational resources to process. These copied data structures enable mobile devices to perform location calculations with reduced computational complexity while maintaining sufficient accuracy
Data Source
AI summary
A system and method for determining one or more satellites in view of a wireless device. A request for satellite assistance data may be received from a requesting entity and a reference location determined as a function of the request. A set of satellites may be determined as a function of the reference location. Subsequent cached information may be determined for each satellite in the set of satellites if cached information already existing for each satellite in the set of satellites has been cached for greater than a predetermined time period. This subsequent cached information may then replace the previously existing cached information for the reference location. One or more satellites in view of the wireless device may then be determined as a function of either the subsequent cached information or previously existing cached information, and assistance data may be provided to the requesting entity to determine an estimated location of the wireless device.