GEM1111 is a high-performance L1 GNSS positioning module with antenna built-in, which is developed on the base of the state-of-the-art Allystar Cynosure III Lite architecture. It supports global civil navigation systems, including GPS, BDS, GLONASS, Galileo, and QZSS. Featured with SAW and LNA, GEM1111 achieves high positioning accuracy and short TTFF, especially in a rough urban environment. It supports antenna supervisor and auto-switching between the built-in antenna and the external antenna.