Sensor Timestamp Correction via Intermediary Controller
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Solution Overview
Problem
Existing sensor data processing systems face challenges in achieving accurate time stamping due to the use of less accurate clock sources and variable delays in data retrieval, which affect the precision of integration operations.
Innovation Solution
A method involving a sensor device with a first clock source for generating data samples and a host processor with a second independent clock source for assigning and adjusting time stamps, using a time stamp controller to determine and apply corrections based on retrieval timing characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a highly accurate clock is used in the sensor for time stamping, then timing precision is improved, but device cost and complexity increase
Solution Approach 1:
The patent introduces a time stamp controller as an intermediary component that mediates between the sensor's inaccurate clock and the host processor's accurate clock. This controller captures timing information from both clock sources and generates corrected time stamps, effectively transferring the timing accuracy function from the sensor to the host processor without requiring hardware changes in the sensor.
Solution Approach 2:
The patent replaces the physical hardware solution (using a highly accurate crystal oscillator in the sensor) with a software-based correction mechanism. By using the time stamp controller to calculate and apply timing corrections algorithmically, the system achieves high timing precision without the complexity and cost of sophisticated clock hardware in the sensor.
2Measurement precision
If the host processor is used to assign time stamps with a more accurate clock, then timing accuracy is improved, but variable delays in data retrieval introduce timing errors
Solution Approach 1:
The time stamp controller implements a feedback mechanism by continuously monitoring the actual retrieval times of data samples and comparing them with the expected sampling intervals. Based on this feedback, the controller dynamically calculates correction values that compensate for variable delays, ensuring that time stamps accurately reflect the true sampling moments despite processing variations.
Solution Approach 2:
The system performs preliminary timing measurements by recording when data samples are actually retrieved from the buffer. These preliminary observations are used to establish the variable delay characteristics, which are then applied as corrections to generate accurate time stamps for integration operations.
3Adaptability or versatility
If data samples are stored in a buffer for periodic retrieval, then data processing flexibility is improved, but retrieval delays reduce timing precision
Solution Approach 1:
The time stamp controller serves as an intermediary that decouples the buffer retrieval process from the timing requirements of integration operations. It independently generates corrected time stamps based on actual retrieval times, allowing the buffer to operate flexibly for power management and processing optimization without compromising timing precision in the final data stream.
Data Source
AI summary
Systems and methods are disclosed for providing sensor data to a host processor. A sequence of data samples may be generated at a sample rate established by a clock source associated with the sensor. A time stamp derived from another clock source, such as the clock employed by the host processor, is assigned to at least one of each periodically retrieved data samples. As such, at least one of the assigned time stamps then may be adjusted by applying a correction determined from a timing characteristic associated with retrieval of the data samples.