APM 3G vehicle tracker built-in GPS+GLONASS with AGPS support and 3G UMTS/HSPA+ modules, the tracker is a very sensitive, live car GPS tracker. The sensitive GPS always fixes position even in GPS difficult environment (weak GPS signal). Both GPS+GLONASS and 3G antennas are built-in, no antenna wiring demand. It’s compact and very easy to hide it from driver’s sight. With built-in big Li-ion battery and charging circuit, tracker continues working, alerts its guardian/manager if the external power is tampered (removed) by accidental or malicious users.