Time Synchronization Unit for Sensor Timestamp Alignment

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Solution Overview

Problem

Existing information processing systems face challenges in synchronizing the time at which data is acquired by sensors with the system time of an information processing apparatus, especially when sensors operate with different timing signals.

Innovation Solution

The implementation of a time synchronization method within an information processing apparatus that includes a time synchronization unit capable of converting and attaching accurate timestamps to data packets, using a combination of hardware and software-based control to synchronize the acquisition time of sensors with the system time, independent of communication delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sensors operate with different timing signals independently, then each sensor can function autonomously with its own timing, but the acquisition times of multiple sensors cannot be synchronized with system time

Engineering Contradiction:
Improveautonomous sensor operationVSAvoidtime synchronization accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces a time synchronization unit as an intermediary component that receives timing information from multiple sensors operating with different timing signals and converts it into unified system time. This mediator enables autonomous sensor operation while achieving accurate time synchronization by acting as a translation layer between independent sensor timebases and the central system time.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional hardware-based time synchronization mechanisms (such as reset signals and centralized clock distribution) with a software-based time synchronization method. The time synchronization unit uses timestamp conversion and calculation algorithms to achieve time alignment without requiring physical intervention or centralized clock control, thereby maintaining sensor autonomy while achieving synchronization.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If hardware-based time synchronization using reset signals is used, then time can be synchronized, but the system complexity increases and requires additional control signals

Engineering Contradiction:
Improvetime synchronization accuracyVSAvoidsynchronization control complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces hardware-based time synchronization mechanisms (such as reset signals and centralized clock distribution) with a software-based time synchronization method. The time synchronization unit uses timestamp conversion and calculation algorithms to achieve time alignment without requiring physical intervention or centralized clock control, thereby maintaining sensor autonomy while achieving synchronization.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the time synchronization function from the hardware control layer and implements it as a separate software module. By taking out the synchronization logic from hardware circuits and placing it in the software domain, the system reduces hardware complexity while maintaining synchronization accuracy through algorithmic time conversion.

Inventive Principle:
Principle #2Taking out (Extraction)

3Loss of information

If timestamps are attached based on sensor local time, then data acquisition timing is recorded, but the timestamps are not synchronized with system time causing temporal misalignment

Engineering Contradiction:
Improvedata acquisition timing informationVSAvoidtimestamp synchronization accuracy
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent changes the time parameter reference frame from local sensor time to system time. The time synchronization unit converts timestamps generated by sensors operating with different timing signals into the system time reference frame through calculation and conversion, ensuring that all timestamps are expressed in a unified temporal coordinate system for accurate temporal alignment.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The time synchronization unit acts as an intermediary that receives local timestamps from sensors and transforms them into system-time-aligned timestamps. This mediator preserves the original data acquisition timing information while re-expressing it in the system time reference frame, thereby maintaining information integrity while achieving synchronization accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If communication delays are considered in time synchronization, then accuracy can be improved, but the synchronization process becomes more complex and computationally intensive

Engineering Contradiction:
Improvetimestamp accuracyVSAvoidsynchronization processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies partial correction for communication delays by focusing on the most significant delay components rather than attempting to model and correct all possible delay sources. The time synchronization unit implements practical delay compensation that addresses the dominant delay factors in the sensor-to-system communication path, achieving sufficient accuracy without the excessive computational complexity of complete delay modeling.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3681171B1Information processing apparatus, time synchronization method, and time synchronization program
Publication Date: 2023.07.19 FUJITSU LTD
  • EP3681171B1 patent drawingFigure 1
  • EP3681171B1 patent drawingFigure 2
  • EP3681171B1 patent drawingFigure 3

AI summary

An information processing apparatus includes: a storage unit that stores first system time; a reception unit that receives, from an information acquisition apparatus after the first system time is written in the storage unit, first information acquired by the information acquisition apparatus and first time information indicating acquisition time of the first information, and receives, from the information acquisition apparatus after receiving the first information and the first time information, second information and second time information indicating acquisition time of the second information; a reception time conversion unit that converts, based on the first system time, reception time at which the reception unit has received the first information and the first time information into second system time; a time information conversion unit that converts, based on the second system time and the first time information, the second time information into third system time; and an attaching unit that attaches the second system time to the first information and attaches the third system time to the second information.