This might become an attachment to some of my more expensive equipment...
Tile
I'm pretty sure i could secure this to my robot and my data collector with a bit of epoxy and a thief would never recognize it as a tracking device.
It is very limited range until many people sign up.
"The range from your phone is 50 - 150ft depending on the environment. However, if any other Tile user's phone is within 50 - 150ft of your Tile, you will receive an update with the location of your Tile. When this happens, you will see a pin on the map view for your Tile. This essentially makes the range limitless once there are enough Tile users in your area."
I did see something about the newest Topcons having built in tracking and the ability to shut it off and lock it if it is stolen. Kinda like a Low-jack.