GPS Cold Start Using Pre-stored Ephemeris Data
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Solution Overview
Problem
The existing cold start method for GPS modules is inefficient, requiring a long time to acquire ephemeris data in real time through satellite-orbit modeling, leading to poor user experience and satisfaction.
Innovation Solution
A method that involves acquiring target position information, selecting an ephemeris data record from a preset satellite visible window table, and forming a visible satellite list to perform positioning, significantly reducing the cold start time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ephemeris data is acquired in real time during cold start through satellite-orbit modeling, then positioning can be performed, but the calculation amount is large and a long time is consumed
Solution Approach 1:
The patent applies preliminary action by pre-storing ephemeris data and almanac data in the terminal before cold start occurs. The terminal maintains a database with historical positioning data and satellite information, allowing rapid retrieval during cold start without performing time-consuming real-time satellite-orbit modeling. This pre-prepared data enables the system to skip the lengthy data acquisition phase and proceed directly to positioning calculation.
Solution Approach 2:
The patent uses copying by creating a simplified copy of the complete ephemeris data and almanac data in the terminal's local database. Instead of acquiring the full real-time ephemeris data from satellites during cold start, the terminal uses pre-copied and processed data that replicates the necessary positioning information, significantly reducing the data acquisition time and calculation burden.
2Measurement precision
If complete ephemeris data is acquired in real time during cold start, then positioning accuracy can be achieved, but the calculation amount is large
Solution Approach 1:
The patent applies extraction by selectively retrieving only the necessary ephemeris data and almanac data from the pre-stored database based on the current positioning requirements and visible satellites. Instead of processing complete real-time ephemeris data for all satellites, the system extracts and processes only the relevant data for satellites currently in view, reducing calculation complexity while maintaining positioning accuracy.
Solution Approach 2:
The patent uses segmentation by dividing the ephemeris data and almanac data into manageable segments and storing them in the terminal database. The system then processes these segmented data portions based on which satellites are visible and which data is currently needed, rather than handling the complete dataset at once, thereby reducing computational burden while preserving accuracy.
3Reliability
If real-time ephemeris data acquisition is performed during cold start, then positioning can be established, but user experience and satisfaction are poor
Solution Approach 1:
The patent applies preliminary action by pre-loading and pre-processing ephemeris data and almanac data into the terminal before cold start occurs. This preparation eliminates the need for users to wait through lengthy real-time data acquisition processes, as the necessary positioning data is already available in the terminal's database, enabling rapid positioning establishment and improving user experience.
Data Source
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AI summary
Provided are a cold start method and apparatus of a global positioning system, GPS, module of a terminal, a terminal and a storage medium. The method includes acquiring (S110) target position information of the terminal; selecting (S120), according to the target position information, an ephemeris data record whose position information matches the target position information from a preset satellite visible window table to obtain a target record set; selecting (S130) N satellites according to the ephemeris data record in the target record set to form a visible satellite list, where N is an integer greater than or equal to 4; and positioning (S140) according to the satellites in the visible satellite list.