For large-site survey applications requiring extremely accurate horizontal and vertical measurements, the Center operates one Trimble 5800 Receiver/Antenna combination, one Trimble 5700 with a Zephyr antenna, and one 5700 Trimble 5700 with a Zephyr Geodetic antenna. This combination of geodetic grade GPS equipment is configured to operate in static, fast-static, and real-time kinematic (RTK) modes. In static and fast-static modes, all three receivers can be integrated in a classic trilateration network configuration or simply act to measure base-lines between two receivers at a time. In RTK mode, the 5800 and 5700/Zephyr operate as rovers linked with the 5700/Zephyr Geodetic base station.
In addition, all three receiver/antenna combinations can be configured with data modems to communicate with an established NetRS base station operating from the top of the University of Arkansas Science and Engineering Building. The NetRS receiver is owned by DCI Engineering of Little Rock, AR and jointly operated with CAST. Real-time network solutions using the NetRS are available for research activities in and around Northwest Arkansas and archived observations are available via ftp. All of these GPS observations can be easily integrated with traditional EDM and angle measurements from the Trimble 5600 Robotic Total Station in a least-squares adjustment using the Trimble’s Geomatics Office.