The whole project is built around the bmc::boards' "mini::base" and "mini::grid" which is currently avaliable on CrowdSupply.

mini::base is an STM32F103 MCU board with many auxiliary features, including a CAN transceiver with hardware filter and ESD protection, a microSD card slot, a 24 V power supply, an atmospheric sensor, USB Type-C support, and much more. Its compact, 54 x 42.5 mm form factor is designed to host one of the various expansion boards.

mini::grid is based around the SIMCOM SIM868, which supports GPS L1 C/A code and quad-band GSM connectivity. Antennas can be connected via U.FL connectors, and a nano-SIM-card slot is located on the back. A pair of Binder subminiature connectors carries power and data to and from mini::grid.

After connecting some antennas to the board and powering it up, the first step is to send some "AT" commands to the SIM868 module to gather basic information about the module and of course, the position. The code can be found here. My first test can be seen in this video: