Inertial Tracking Synchronization via Time Offset Estimation
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Solution Overview
Problem
Existing tracking systems face challenges in synchronizing inertial measurement unit (IMU) and exteroceptive sensor data without a common electrical measurement trigger signal, leading to inaccuracies in state estimation due to asynchronous sampling rates and lack of interoperability across different sensor types.
Innovation Solution
A controller-based method that synchronizes IMU and exteroceptive sensor data by estimating a time offset to align their respective time series, allowing for inertial-aided tracking by minimizing errors and separating sensor-specific processing to facilitate flexible integration of various sensor types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If IMU and exteroceptive sensor data are synchronized without a common electrical measurement trigger signal, then system complexity is reduced and adaptability is improved, but measurement precision and reliability deteriorate due to asynchronous sampling rates
Solution Approach 1:
The patent introduces an intermediary time offset estimation mechanism that mediates between asynchronous IMU and exteroceptive sensor data streams. By estimating and compensating for time offsets without requiring hardware-level synchronization signals, the system achieves precise temporal alignment of data from sensors with different sampling rates, thereby maintaining measurement precision while preserving system adaptability
Solution Approach 2:
The patent dynamically adjusts temporal parameters (time offsets, sampling rate ratios) to synchronize asynchronous sensor data. By treating time synchronization as a parameter optimization problem rather than a hardware constraint, the system adapts to different sensor configurations and sampling rates while maintaining consistent measurement precision across varying operational conditions
2Ease of operation
If sensor-specific processing is separated for different sensor types, then ease of operation and adaptability are improved, but device complexity increases due to multiple processing pipelines
Solution Approach 1:
The patent segments the tracking system into independent sensor-specific processing modules, each handling data from a particular sensor type (IMU, exteroceptive sensors) with optimized algorithms tailored to that sensor's characteristics. This modular segmentation allows each module to operate independently with ease while maintaining overall system coherence through a unified state estimation framework
Solution Approach 2:
The patent implements a universal state estimation framework that processes outputs from multiple sensor-specific modules. This universal processor integrates diverse sensor data streams using a common mathematical model, allowing the system to maintain simplicity in the integration layer while accommodating complexity in individual sensor processing pipelines through standardized interfaces
Data Source
AI summary
A system and method for generating a tracking state for a device includes synchronizing measurement data from exteroceptive sensors and an inertial measurement unit (IMU). A processing unit is programmed to offset one of the measurement signals by a time offset that minimizes a total error between a change in rotation of the device predicted by the exteroceptive sensor data over a time interval defined by an exteroceptive sensor sampling rate and a change in rotation of the device predicted by the IMU sensor data over the time interval.