RTK upgrade kit for the SonTek-RS5. Includes RTK Rover, consisting of SonTek RTK GNSS smart antenna and 3-ft (91-cm) interface cable; RTK Base Station, consisting of SonTek RTK GNSS base station antenna; (2) Li-Ion rechargeable batteries, tripod, and mounting hardware/adapters; and GNSS firmware unlock for the SonTek-RS5 system.