“with the new upgrade, called Mars Global Localization, Perseverance can match its own panoramic imagery to orbital terrain maps onboard, calculate its precise position and continue along its planned route without waiting for Earth-based confirmation.

An onboard algorithm performs the comparison in about two minutes and can pinpoint the rover's location to within roughly 10 inches (25 centimeters), all without assistance from human planners”

https://www.space.com/space-exploration/mars-rovers/nasas-perseverance-rover-now-has-its-own-gps-on-mars-weve-given-the-rover-a-new-ability

I read about this on Mastodon, (I think) sounds pretty cool. Hopefully extend the life of the mission.