Smart Card Clock Drift Detection for Remote Synchronization
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Solution Overview
Problem
Existing smart card manufacturing processes require lengthy calibration procedures to synchronize clocks with reference times, which are prone to errors and can lead to desynchronization, increasing manufacturing time and scrap rates due to environmental factors and clock drift.
Innovation Solution
A method implemented by a server to determine smart card behavior by calculating time drift based on reference time data, eliminating the need for on-card calibration and allowing continuous synchronization throughout the card's lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional on-card calibration is performed during manufacturing, then clock synchronization is achieved, but manufacturing time is significantly extended
Solution Approach 1:
The calibration function is extracted from the smart card itself and transferred to an external server. The server performs all calibration operations remotely by receiving time data from the card's clock, calculating drift, and determining behavior characteristics, eliminating the need for prolonged on-card calibration procedures during manufacturing.
Solution Approach 2:
The system implements a feedback mechanism where the server receives time data from the smart card clock, compares it with reference time, calculates time drift, and uses this information to determine card behavior and perform corrections remotely, enabling continuous synchronization without extended manufacturing calibration.
2Measurement precision
If multiple calibration steps are performed to ensure accurate time drift correction, then clock synchronization precision is improved, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The server acts as an intermediary that consolidates all calibration operations. Instead of performing multiple calibration steps on the card itself, the server receives time data, performs reference comparisons, calculates drift, and manages corrections centrally, simplifying the overall process while maintaining precision.
Solution Approach 2:
The system changes the approach from iterative on-card calibration to a single remote parameter measurement. The server measures time drift once by comparing card clock data with reference time, then uses this parameter to determine card behavior and apply corrections, eliminating the need for repeated calibration cycles.
3Reliability
If calibration data is recorded during manufacturing to correct time drift, then clock accuracy is improved, but the process requires repeated calibration cycles extending manufacturing time
Solution Approach 1:
The server performs preliminary calibration actions by receiving time data from the card clock during or after manufacturing, calculating drift before the card enters service, and establishing behavior characteristics in advance, eliminating the need for repeated calibration cycles during manufacturing.
Solution Approach 2:
The smart card clock operates autonomously using its oscillator, and the server performs calibration remotely without requiring the card to undergo extended manufacturing calibration cycles. The card provides its time data, and the server handles all calibration operations externally.
4Manufacturing precision
If traditional calibration methods are used, then initial clock synchronization is achieved, but they cannot account for timing drift changes after card distribution
Solution Approach 1:
The calibration process becomes continuous rather than a one-time manufacturing step. The server can receive time data from the card clock at any point during the card's lifetime, recalculate drift based on current conditions, and update behavior characteristics, enabling ongoing adaptation to environmental changes.
Solution Approach 2:
The system transitions from static manufacturing calibration to dynamic remote calibration. The server can adapt calibration parameters based on real-time drift measurements and environmental factors encountered during card usage, making the system responsive to changing conditions throughout the card's operational life.
Data Source
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AI summary
The invention essentially relates to a method for determining the behavior of a smart card, called the first smart card, implemented by a server, comprising the following steps: - obtaining (S310, S320) a first reference time data (Tr1) corresponding to a time setting of a smart card clock, and a second reference time data (Tr2) corresponding to a time reading of a first time data of said clock, - determination (S330) of a time drift (dt) associated with the first smart card as a function of said first reference time data (Tr1) and said second reference time data (Tr2), - determination (S340) of a behavior of the first smart card from said time drift (dt).