Synchronizing the data of 2 subdevices within 1 device.

I am currently trying to figure out how to Sync up my IMU data. Within this IMU there is an Accelerometer and Gyroscope that get data with 200Hz and an GNSS that gets data with 10Hz. The ultimate goal is using the script(when its done) for event detection. Within the GNSS data I get is a POSIX time and a 'timestamp[us]' in the IMU data is only the 'timestamp[us]. Does anyone have an idea on how I could manage to sync these two time variables so I can view real time events within matlab eventhough they have different frequencies.