Lots of software running with gps.
You can find here via search good layman's decriptions of the process and particularly time to first lock on a unit that can take as long as 15 minutes. A short lock time results from the unit "remembering" the last position.
Structure and weather coverage can hinder lock.
My gps module needed a specific side facing the sky, but the "labeling" was configured for back of mirror attachment or opposite of windshield mounting. Bought a replacement module before understanding.