Chip Card Trusted Time Reference via Satellite Synchronization
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Solution Overview
Problem
Chip cards used in terminals face challenges in providing a trusted absolute time reference, as their internal batteries may drain before use, and reliance on external network connections or satellite signals is unreliable, especially when interchanged between terminals.
Innovation Solution
Integration of a signal receiver within the chip card to access satellite navigation signals for continuous time synchronization, combined with an internal power source and microcontroller to manage power usage and secure the time reference, ensuring independence from external networks and terminal positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the chip card uses an internal battery to run the clock unit, then the time reference can be maintained when external power is interrupted, but the battery may run empty before the chip card is used or during rare usage intervals
Solution Approach 1:
The chip card synchronizes its clock with external time sources (network time protocol or GPS satellite signals) before the battery is depleted, ensuring the time reference remains accurate. This preliminary synchronization action prevents the problem of battery exhaustion leading to time loss.
Solution Approach 2:
The chip card implements feedback mechanisms by periodically checking and synchronizing its internal clock with external time sources when power is available, and maintaining its last known accurate time when power is interrupted. This feedback loop ensures continuous time reference reliability.
2Measurement precision
If the chip card relies on external network connections for time synchronization, then accurate time reference can be provided, but the solution introduces dependencies on external elements and requires ubiquitous network availability
Solution Approach 1:
The chip card uses GPS satellite signals as an intermediary time source that provides accurate time reference without requiring dependency on terrestrial network infrastructure. This intermediary approach maintains precision while enhancing independence and adaptability to various operating environments.
Solution Approach 2:
The chip card is designed to support multiple time synchronization methods (network time protocol and GPS satellite signals), making it universally adaptable to different environments where either external source may be available, thus maintaining independence from any single external dependency.
3Ease of operation
If the chip card uses terminal reference for time synchronization, then time can be provided, but the possibility of being interchanged between different terminals provides different synchronization signals making a trusted absolute time reference impossible
Solution Approach 1:
The chip card uses GPS satellite signals as a neutral intermediary time source that is independent of any terminal. This mediator provides a trusted absolute time reference that remains consistent regardless of which terminal the chip card is inserted into, eliminating the reliability issue of terminal-dependent synchronization.
Solution Approach 2:
The time synchronization function is extracted from terminal dependency and implemented independently within the chip card using GPS satellite signals. This extraction ensures the time reference is portable and trusted across different terminals without being influenced by terminal-specific synchronization signals.
Data Source
Figure 1~2
AI summary
The present invention relates to a chip card (1) providing a trusted absolute time reference independently from its position, to a terminal (2) with such a chip card (1) and to a method to operate such a chip card (1). The chip card (1) is suitable to be inserted in terminals (2) and comprises a clock unit (11) to provide a time reference, an internal power source (12) to at least run the clock unit (11) in case of absence of an external power source (22), and a signal receiver (13) to receive a satellite navigation signal comprising a satellite time signal, wherein the signal receiver (13) is connected to the clock unit (11) in order to synchronize the clock unit (11) with the satellite time signal to enable the clock unit (11) to provide the time reference as a trusted absolute time reference independently from the position of the chip card (1).