As an alternative to multi-component base stations, Topcon 's HiPer XT GPS system combines a 2-watt UHF transmit/receive radio and antenna into a single unit. For optimal signal performance, the transmit/receive antenna is located at the top of the unit. HiPer XT functions as a base or rover, and GPS+ technology uses additional satellites to reduce downtime and improve accuracy. It has a 10-hour run time on one charge of the internal batteries. Bluetooth technology allows cable-free wireless communication with field computers.