Vehicle Sensor Timestamp Alignment Using IMU Velocity Latency
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Solution Overview
Problem
Existing advanced driver-assistance systems (ADAS) face challenges in system-level performance evaluation due to the lack of a common time base between reference and test systems, leading to errors and decreased modularity, necessitating a reliable perception evaluation framework.
Innovation Solution
Determine latency between time reference frames using velocity data from the system under test and reference system by minimizing velocity differences through linear regression, incorporating IMU measurements and potentially using GNSS for sensor drift compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no common time base exists between reference system and system under test, then device complexity is reduced, but measurement precision deteriorates due to latency-induced errors
Solution Approach 1:
The patent introduces velocity as an intermediary physical quantity to bridge the time reference frames of the reference system and system under test. By comparing velocities derived from independent time bases, the method indirectly determines latency without requiring direct time synchronization, thus resolving the contradiction between device complexity and measurement precision
Solution Approach 2:
The patent transforms the time synchronization problem into a velocity comparison problem. By changing the parameter from time stamps to velocity values, the method enables latency determination through physical quantity comparison rather than direct time base alignment, maintaining measurement precision while avoiding complex synchronization mechanisms
2Device complexity
If latency determination is performed without velocity comparison, then device complexity is reduced, but measurement precision deteriorates due to uncorrected timestamp offsets
Solution Approach 1:
The patent employs a feedback mechanism where velocity differences between the two systems serve as feedback signals to quantify timestamp offsets. By continuously comparing velocities and using the differences to determine latency, the system achieves precise timestamp alignment through iterative correction rather than complex deterministic synchronization
Solution Approach 2:
The patent replaces complex time synchronization mechanisms with a physics-based velocity comparison approach. Instead of using hardware time synchronization devices or complex software protocols, the method uses fundamental physics principles (velocity-time relationships) to indirectly determine and correct latency, simplifying the overall system while maintaining precision
Data Source
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AI summary
A method is provided for determining a latency between a first time reference frame of a system under test in a host vehicle, and a second time reference frame of a reference system in the host vehicle. The system under test comprises at least one sensor for acquiring sensor data of a surrounding of the host vehicle. The reference system comprises an inertial measurement unit, IMU. A time-dependent first velocity of the host vehicle in the first time reference frame is determined, using the system under test. A time-dependent second velocity of the host vehicle in the second time reference frame is determined, using the reference system. The latency between the first time reference frame and the second time reference frame is computed, using the first velocity and the second velocity.