Event Detection Time Estimation Using System Delay Jitter
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Solution Overview
Problem
Simple sensors lack a system clock for timekeeping, and existing methods require phase locked loops or time synchronization packets to correct clock deviations, making it difficult for the receiving side to accurately estimate the time of event detection.
Innovation Solution
An information processing device with a receiver, reception-time-point measuring unit, minimum-system-delay-time storage, minimum-reception-time expected-reception-time-point storage, jitter estimation unit, and event-detection-time-point estimation unit to calculate and estimate the event detection time point based on system delay time, expected reception time, and jitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If time point synchronization packets are used to control clock synchronization, then the receiving side can accurately grasp the time point at which an event occurred, but the device complexity increases due to requiring PLL or time synchronization packet transmission function
Solution Approach 1:
The patent extracts the time point information from complex synchronization protocols and isolates it as a simple timestamp field in detection data. By separating the essential time information from the complex clock synchronization mechanism, the receiving side can obtain accurate time points without requiring full synchronization infrastructure.
Solution Approach 2:
The patent uses simple timestamps as disposable time markers that are embedded in each detection data packet. These timestamps are lightweight, easy to generate and process, and do not require the complex, expensive synchronization infrastructure of PLL or time synchronization packets.
2Measurement precision
If a system clock is added to the sensor for timekeeping, then the time point can be recorded, but the device complexity and cost increase
Solution Approach 1:
The receiving side performs the time point estimation function that would otherwise require the sensor to have its own system clock. The receiver uses its local clock and the known system delay to calculate the event detection time, allowing the simple sensor to provide time-stamped data without internal timekeeping capability.
Solution Approach 2:
The patent introduces the concept of system delay as an intermediary parameter that bridges the gap between the sensor's detection time and the receiver's reception time. By measuring and compensating for this delay, the receiver can accurately determine when the event occurred at the sensor without the sensor needing its own clock.
3Device complexity
If the transmitting side is a simple sensor without system clock, then the device complexity is reduced, but the receiving side cannot accurately estimate the event detection time point
Solution Approach 1:
The patent uses feedback from the reception time point and the predetermined system delay information to calculate and determine the event detection time point. The receiver measures when data is received, references the known system delay characteristics, and uses this feedback to accurately compute when the event occurred at the sensor.
Solution Approach 2:
The system delay time is predetermined and stored in advance before actual detection occurs. By pre-characterizing the transmission and processing delay, the receiving side can simply add this known delay to the reception time to accurately determine the event detection time without requiring complex real-time synchronization.
Data Source
AI summary
An information processing device includes a reception I/F unit, a reception-time-point measuring unit, and an event-detection-time-point estimation unit. The event-detection-time-point estimation unit estimates an event detection time point, which is a time point at which an event corresponding to latest detection data is detected, from a minimum system delay time, a minimum-system-delay jitter, and a time period from detection of the event corresponding to a target data to detection of the event corresponding to latest detection data. The minimum-system-delay jitter is the difference between a minimum-reception-time expected reception time point and the reception time point of the target detection data. The minimum-reception-time expected reception time point is calculated to be a time point at which the target data is received before the latest detection data. The target detection data is one piece of detection data, out of the multiple pieces of detection data, sent with a minimum system delay time.