A compact multi-constellation RTK GNSS receiver tracking GPS, BeiDou, GLONASS, Galileo and QZSS signals with hot-swappable batteries and a built-in 4G/2G modem for CORS connectivity. It reaches roughly 8mm+1ppm horizontal RTK accuracy with sub-10-second initialization, and offers WiFi, UHF and Bluetooth links plus 8GB of onboard storage for field data.