Understanding Ground Distance Accuracy (1 Sigma)

I’m using the GNSS arduino library from sparkfun and want to use the built in odometer functionality of the GPS to record my distance traveled. Currently I’m still in testing so I’m inside a building (I know that’s bad with GPS), so it’s not too surprising that my odometer quickly accumulates distance even though I’m sitting still because the signal is jumping around all over the place.

If, however, it turns out my distance traveled is still WAAAAY off once I’m out in the open I’d like to try to make use of distance accuracy to filter out my reads. In the library from Sparkfun it lists an entry named “distanceSTD” and notes it as “Ground distance accuracy (1-sigma): m” and polling it returns a value of 532 (for me, inside)

What does 532 mean? That my position is accurate within a radius of 532 meters?