IEEE 1588-Based General and Precise Time Synchronization Method for Multiple Sensors

Abstract

An increasing number of robotic systems contain multiple sensors, and the accurate timestamps of sensors are crucial for fusing multiple sensors information in robot applications. However, the accuracy and stability of traditional timestamp synchronization algorithms are degraded when synchronizing the timestamps of multiple sensors, due to the clock inconsistency, asynchronous trigger delay, and variable transmission delay. This paper presents a general and precise time synchronization method for multiple sensors with respect to a local clock (i.e. typically a computer’s internal clock). First, to reduce the software scheduling delay, an IEEE 1588-based method, which combines hardware and software to obtain timestamps, is formulated to modify the master-slave timestamp acquisition location. Second, a hardware synchronization trigger method is proposed to reduce the runtime of trigger threads in the software, by introducing the microprocessor to trigger multiple sensors synchronously. Finally, a timestamp matching method is proposed to reduce the unreliability of variable communication delays by matching the trigger timestamp and the timestamp of data reception. To the best of our knowledge, this approach is the first synchronization method to combine hardware and software to obtain the timestamps of multiple sensors. Results show that the ability of our method can estimate time offset to microsecond accuracy.