The Syncline Model -- Analyzing the Impact of Time Synchronization in Sensor Fusion
Erling Rennemo Jellum, Torleiv Håland Bryne, Tor Arne Johansen, Milica Orlandíc
TL;DR
Problem: Sensor fusion accuracy is constrained by intrinsic sensor noise and time synchronization errors, with the impact of synchronization depending on platform dynamics. Approach: The Syncline introduces a simple, visual, upper-bound error model where $\delta_{syncline}(\tau) = \delta_{sync}^*(\tau) + \delta_{sensor}^*$ with $\delta_{sync}^*(\tau) = v_{max}\tau + d\,\omega_{max}\tau$ and $\delta_{sensor}^* = \sigma_p + \sigma_r + (\sigma_\Theta + \sigma_u)d$, enabling quick assessment of required synchronization precision. It is applied to two representative scenarios—direct georeferencing with GNSS/INS/LiDAR and SV/AUV subsea mapping—by deriving analytical measurements and comparing with Syncline predictions to extract $\tau_{crit}$ per sensor. Findings show the roof (intrinsic sensor accuracy) and slope (synchronization sensitivity) behavior and that slower platforms can be limited by sensor noise, while fast dynamics shift sensitivity to synchronization. Significance: The framework helps system designers choose synchronization primitives and timing requirements to maximize sensor usage without over-investment.
Abstract
The accuracy of sensor fusion algorithms are limited by either the intrinsic sensor noise, or by the quality of time synchronization of the sensors. While the intrinsic sensor noise only depends on the respective sensors, the error induced by quality of, or lack of, synchronization depends on the dynamics of the vehicles and robotic system and the magnitude of time synchronization errors. To meet their sensor fusion requirements, system designers must consider both which sensor to use and also how to synchronize them. This paper presents the Syncline model, a simple visual model of how time synchronization affects the accuracy of sensor fusion for different mobile robot platform. The model can serve as a simple tool to determine which synchronization mechanisms should be used.