Mini GPS/BDS Unit M5Stack Mini GPS/BDS Unit is an M5Core-compatible module that provides BDS/GPS/GLONASS satellite positioning to M5Stack applications. The Mini GPS/BDS Unit is based on the AT6558 Navigation IC, which can receive satellite signals over 56 GNSS channels. The GNSS signals cover Galileo in Europe, NAVSTAR in America, GLONASS in Russia, and BeiDou/Compass in China.