Daniel's device for determining when it is

As Sawyer and Juliet recommend taking the zodiac raft to a shipping lane, Daniel says that in order to that, he will need to calculate a new bearing. He pulls out a shiny gold device and states in order to do that "I'll need to determine where we are now, in time." There is never a clear image of the device, but I did my best to capture it.

What is this device and how will it determine when it is? Also, he Daniel just stalling? If he needs to know when it is to determine the bearing, they would lose that bearing each time the island skips.