Wishlist of Additional Equipment
G&G High-Precision GPS
In rough order of importance
Solar array for base station occupations - long-term unattended surveys need this sort of option. This should cost $100-$300 altogether.
Log books for the instruments, so unusual events can be recorded when they happen in the field.
4 or more batteries for the rover - used in sets of 2, and can be charged in sets of 4 (per OSM). 2 batteries provides power for 8 hours of operation.
Additional base station and base radio batteries, in case a battery dies.
Comments and questions are welcome.