Sensor Timestamping via Sampling Rate Estimation
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Solution Overview
Problem
Existing methods for associating timestamps with sensor samples, such as those generated by gyroscopes in electronic devices, often result in inaccurate timestamping due to the processor applying timestamps asynchronously, leading to delays and inaccuracies in determining the orientation of the device.
Innovation Solution
A processor-implemented method that estimates the sampling rate of the sensor, determines an expected sample time based on this rate, and assigns a timestamp to the sensor sample by combining the expected sample time with the reporting time, which is the time the sample is detected, to improve the accuracy of timestamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the processor applies timestamps asynchronously to sensor samples, then the processor can perform other functions, but the timestamp accuracy deteriorates due to delays
Solution Approach 1:
The system performs preliminary actions by estimating the sampling rate and calculating expected sample times in advance. The processor determines a sampling rate estimate for the sensor and uses this to calculate when samples are expected to occur, allowing it to prepare timestamp values before actually receiving the samples, thereby reducing delays while maintaining processor productivity
Solution Approach 2:
The system implements feedback by continuously monitoring the difference between expected sample times and actual sample arrival times. When a sample is received, the system compares its actual timestamp with the expected timestamp and uses this feedback to refine future timestamp assignments, improving accuracy while maintaining processor efficiency
2Measurement precision
If the processor waits for sensor samples before applying timestamps, then timestamp accuracy improves, but processor productivity deteriorates
Solution Approach 1:
The processor performs preliminary calculations to determine expected sample times based on estimated sampling rates before actual samples arrive. This allows the processor to prepare timestamp values in advance rather than waiting idle for samples, maintaining both accuracy and productivity
Solution Approach 2:
The system uses the sensor's own sampling rate characteristics to generate expected timestamp values. By leveraging the inherent periodicity of sensor sampling, the processor can autonomously generate accurate timestamp estimates without continuous waiting or complex synchronization, improving both accuracy and efficiency
Data Source
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AI summary
Methods and devices for determining a timestamp that represents a time a sensor sample was generated are described. In one aspect, a method includes: obtaining a sampling rate estimate for the sensor; determining an expected sample time based on the sampling rate estimate; detecting a sensor sample and assigning a reporting time to the detected sensor sample, the reporting time representing the time when the sensor sample was detected; and determining the timestamp for the sensor sample based on the expected sample time and the reporting time.