Positioning Control Apparatus Switching Predictive Ephemeris Data
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Solution Overview
Problem
Conventional GPS positioning technologies using predictive ephemeris data face challenges in maintaining location accuracy over time, as the accuracy decreases with days elapsed since data acquisition, leading to increased positioning times and errors.
Innovation Solution
A positioning control apparatus that acquires predictive ephemeris data and switches its usage based on a predetermined condition related to the expiration date and required location accuracy level, allowing its use for both satellite search and positioning calculation within specified time frames to maintain accuracy and reduce search time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If predictive ephemeris data is used for positioning calculation, then positioning time is shortened, but location accuracy deteriorates over time
Solution Approach 1:
The system dynamically switches between using predictive ephemeris data and actual ephemeris data based on the elapsed time since data acquisition. A determination unit evaluates whether to use predictive data for satellite search and positioning calculation by comparing the elapsed time against threshold values, thereby adapting the positioning method to current conditions to maintain accuracy while benefiting from shortened positioning time when appropriate
Solution Approach 2:
The system changes the parameter of ephemeris data usage (predictive vs. actual) based on the time parameter. By monitoring the elapsed time since ephemeris data acquisition and comparing it with predetermined thresholds, the system adjusts whether to use predictive ephemeris data for satellite search and positioning calculation, optimizing the balance between positioning speed and accuracy according to temporal conditions
2Productivity
If predictive ephemeris data is used beyond expiration date, then positioning can be performed, but positioning errors increase
Solution Approach 1:
The system performs preliminary determination before using predictive ephemeris data for positioning calculation. The determination unit evaluates whether the elapsed time since ephemeris data acquisition is within a predetermined threshold, and only allows predictive data usage when this condition is met, preventing inaccurate positioning results from using expired data
Solution Approach 2:
The system implements feedback control by continuously monitoring the elapsed time since ephemeris data acquisition and using this information to determine whether predictive ephemeris data should be used. The determination unit provides feedback on data freshness, and the control unit adjusts data usage decisions accordingly, ensuring positioning accuracy is maintained by preventing use of outdated predictive data
Data Source
AI summary
A positioning control apparatus is provided, which includes: an acquisition unit that acquires predictive ephemeris data from outside of the positioning control apparatus; a setup unit that sets up, based on a predetermined condition different from an expiration date that has been set up in the predictive ephemeris data, a switching condition as to whether the predictive ephemeris data acquired by way of the acquisition unit should be used for positioning calculation to calculate location information that indicates a current location of the positioning control apparatus; and a control unit that switches, based on the switching condition that has been set up by way of the setup unit, whether the predictive ephemeris data should be used for the positioning calculation.