Preamble:
As an experiment I bought a relatively cheap GPS tracker that supported 3G (most of them at the time were 2G only).
After quick google search I found a suitable model GT06E from Concox.
The idea was I would implement my own server, as I do not trust 3rd party GPS tracking services (who would?), especially free ones ;).
I did not realise at the time what a mess the protocol is.
The “engineers” who wrote the spec for the protocol are crazy! They reinvented the wheel, which instead of tyre utilizes boots.
Continue reading GT06E GPS Tracker Part 1: Implementing communication protocol – WTF is CRC-ITU???