M2R
A close up of the GPS section of an M2R, Martlet 2's radio board.
The radio board features a uBlox MAX-M8Q GPS with an LNA+SAW on the input, a Radiometrix MTX2 which can either connect directly to the output or go via a 500mW RF power amplifier, and an isolated connection to a RockBLOCK Iridium satellite modem. It's all powered by an STM32F303CBT7 microcontroller.
Fore more details on the schematics, see: www.cusf.co.uk/2014/07/martlet-2-electronics-schematics/
The PCBs were sponsored by Cambridge Circuit company, thank you! The Radiometrix MTX2s were sponsored by Radiometrix, also a big thank you!