What does it mean to "calibrate" a Garmin G600

[MtnMarcus]

I looked at a 182 today that is equipped with G600. The owner told me it costs about $2,500 a yr to "calibrate" this system and made it sound like this "calibration" was specific to G600 and independent of the 24 month IFR cert. What was he talking about? database currency? I am new to glass panels, so any insight would be appreciated. Thx

 

[N747JB]

I'm coming up to the end of my first year of owning a G600 system and I've never heard of calibrating it, maybe that's my 1 year anniversary surprise!
My database updates are about $1000.00 per year, that's for the G600 AND both the GTN 650 and 750. That doesn't include terrain updates, which are not part of the "bundle" I think they are couple hundred or so to update.
I'd get more info from the seller, it's probably a G500 system, that's what is normally used in airplanes under 6000 lbs.
It's a great system, check and see how the autopilot is coupled and if the the flight director works. It seems when a newer display, like the G600 or Aspen is installed, not all the features and functions will work with every airplane and autopilot.

I looked at a 182 today that is equipped with G600. The owner told me it costs about $2,500 a yr to "calibrate" this system and made it sound like this "calibration" was specific to G600 and independent of the 24 month IFR cert. What was he talking about? database currency? I am new to glass panels, so any insight would be appreciated. Thx