As part of my PhD field work it would be useful to have latitude/longitude measurements for the locations of ant nests that I am working on. These ant nests can be as close as 50cm together so the accuracy of the system would (I think) need to be higher than is available from a phone or basic GPS system. Does anyone know what system would be best for getting this sort of accuracy? My budget is probably only around £200. If it isn't possible in that price range it would be good to know what system I would need to use so that I can see if I can just borrow such a system.
Thanks a lot!