This article explains it a little. It’s basically the amount of deviation when it switches to PPVS.
Based on your description, I think you have a bad right antenna. The single antenna mode explains why this works, but it has to drive a bit to get its heading if the right antenna is broken or obstructed. Have a spare you can swap in?
It’s already using 2 replacement antennae, but that is the refurb unit I just received that was shipped upside down with scotch tape. Another replacement is on the way. I’ll just wait for that one. Fingers crossed, here’s hoping!
Here’s my concern - I don’t trust PPVS at all. It’s caused too many issues for my (including the damage that has led to my journey of 3 failed replacements and 5 weeks without a rover). But I need to enable it for some unknown reason in order to enable gentle contact. So what I’m trying to figure out is whether or not it’s actually using Vision 95+% of the time (and using it very well - hence the 0.00), or if there’s another issue at play that is forcing 0.00 to show the bulk of the time, meaning it’s using GPS but for some reason showing 0.00.
0 is good. That means there is zero error. Any number that is incrementing there is that much in meters of error. The higher the number, the higher the error. If you don’t trust PPVS, then back the settings down to whatever you are comfortable with the rover traveling without GPS (boundary, in area, mapping). The lower the PPVS setting, the quicker it will stop and wait for GPS to recover back to no error (0.00).