A passive solution to the sensor synchronization problem

Knowing the time at which sensors acquired data is critical to the proper processing and interpretation of that data, particularly for mobile robots attempting to project sensor data into a consistent coordinate frame. Unfortunately, many popular commercial sensors provide no support for synchronization, rendering conventional synchronization algorithms useless. In this paper, we describe a passive synchronization algorithm that can significantly reduce timing error versus naively time-stamping sensor data when it arrives at the host. It is passive in the sense that the algorithm requires no special cooperation from the sensor. Our method estimates the timing jitter induced by hosts, and thus does not require a real-time operating system. We rigorously derive and characterize the method, proving that it can only improve upon the synchronization accuracy of the standard approach.