A global resource locator (GRL) device can be used to track a physical asset. The GRL device can include a miniature atomic clock (MAC) and a processor communicatively coupled to the MAC. The processor can be configured to calculate a first location of the GRL device at a first time based on the MAC and determine that the first location is outside of a particular geofence. The processor can be configured to calculate a second location of the GRL device at a second time based on the MAC and determine that the second location is within the particular geofence. The processor can be configured to generate an event indicating the GRL device has crossed a border into the particular geofence based on the second location being inside of the particular geofence.