When taking your observations the user interface of the antenna should be facing due north. It’s how the position the antenna was in when the phase center of the antenna was found. it’s a minor thing, but gives the best results.
rjherman, thank you; we’ll face it north. I didn’t know to do that. We have another survey gps and we face that antenna north also; previously, I didn’t know the reason for that.
Thanks to all for the great suggestions!
I just wanted to separately note @rjherman’s advice since I don’t remember seeing this tip on the forum before. Turning the receiver in the same direction shouldn’t affect the accuracy significantly, but it indeed ensures better repeatability of measurements.