Hi Pat, I hope that you are well and clear of the virus, going mad over here. I am looking at the new ublox module ZED-F9P it makes an rtk system. I wonder if anybody on the forum would have any knowledge or know somebody with the knowledge. It would help us with 1 cm accuracy and they are a lot cheaper than buying the 520 with it on , that's right it is still coming out. Johnno Hennessy.