GNSS Receiver TTFF Reduction via Non-Volatile Ephemeris Storage
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Solution Overview
Problem
Conventional GNSS receivers rely on a real-time clock (RTC) for initial time acquisition, leading to performance malfunctions and environmental concerns due to the need for a button battery, which increases costs and environmental unfriendliness.
Innovation Solution
Storing ephemeris information in a non-volatile memory before powering down allows the GNSS receiver to determine time without an RTC, reducing Time To First Fix (TTFF) and eliminating the need for a button battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a real-time clock (RTC) is used for initial time acquisition, then time accuracy is improved, but device complexity and cost increase due to additional components
Solution Approach 1:
The patent extracts and removes the RTC component from the GNSS receiver system. Instead of using a dedicated RTC hardware component, the invention utilizes ephemeris information stored in non-volatile memory to derive time, thereby eliminating the need for separate RTC hardware and reducing device complexity.
Solution Approach 2:
The patent makes the ephemeris data serve multiple functions: it provides both orbital information for satellite positioning and time information for synchronization. By deriving GNSS time from ephemeris data that is already being processed for position calculation, the system achieves multi-functionality without adding dedicated time-keeping hardware.
2Duration of action of stationary object
If a real-time clock (RTC) with button battery is used, then time continuity is improved, but environmental harm increases due to battery waste
Solution Approach 1:
The patent removes the button battery component from the system by eliminating the RTC. Since no RTC is used, no button battery is required, thereby eliminating the source of environmental harm associated with battery disposal while maintaining time continuity through alternative means.
Solution Approach 2:
The patent converts the potential harm of requiring a button battery into a benefit by using power-free non-volatile memory. The ephemeris information is stored in non-volatile memory that retains data without power, turning what would have been a harmful dependency (battery) into a beneficial feature (power-free operation).
3Device complexity
If ephemeris information is stored and used for time determination, then device complexity is reduced, but TTFF increases due to additional processing requirements
Solution Approach 1:
The patent performs preliminary action by storing ephemeris information in non-volatile memory before the receiver is powered off. This pre-stored data is immediately available when the receiver starts up, eliminating the need for real-time clock operations and reducing TTFF despite the additional processing required to extract time from ephemeris data.
Data Source
AI summary
A method for reducing Time To First Fix (TTFF) of a Global Navigation Satellite System (GNSS) receiver includes storing ephemeris information into a non-volatile memory, and utilizing the ephemeris information to determine a GNSS time, in order to reduce the TTFF. An apparatus for reducing TTFF of a GNSS receiver includes a storage module and a processing module coupled to the storage module. The storage module is utilized for storing data, wherein the stored data in the storage module is non-volatile. The processing module stores ephemeris information into the storage module and utilizes the ephemeris information to determine a GNSS time, in order to reduce the TTFF.