I'm not sure if this question can be asked in this forum, but here it goes. I am on my way to conduct some remote sensing research in Vietnam, which includes logging of coordinates. This should preferably be done with the most exact measure i can get, and I have three hardware options to do this. I have the possibility of bringing a Trimble R8, a Trimble Pathfinder XRS and an ordinary GPS handheld receiver. The R8 works with GPS satellites and reference stations on ground, and the Pathfinder XRS supposedly does the same but with beacon stations instead of reference stations. The handheld GPS works with satellite only and therefore delivers the least precise measurement.
My questions is whether or not reference stations or beacons are located in close vicinity of northern Vietnam, Hanoi. I've looked upon Trimbles website and found a list, but it seems to me that it is deficient in some way. Have you had any experience working with this kind of equipment in Vietnam?