RX TX , GSM & GPS Modules

3DR Radio Telemetry Kit, 433 MHz, 500 mW/100 mW Radio Telemetry, 433 MHz and 915 MHz Air and Ground Data Transmit Module for APM 2.6 and 2.8 Pixhawk Flight Control

The Ublox GPS module has a serial TTL output; it has four pins: TX, RX, VCC, and GND. You can download the u-center software for changing the settings, and much more.

U BLOX NEO-6M NEO6MV2 GPS Module