Thanks that is a great tear down pic. I wish I had the guts to take mine apart like that. The reason I am not using a GPS tracker like RF-V16 is that we are building a platform to accept location and telemetry that can strap on any drone. (It worked fine on the Solo, but the mavic has far less strappable real estate) If the the loc update happens to be in a "no flyzone" it will set off alarms on the tracker which will flash leds and sound an alarm. But I guess the real reason is that we need to customize the endpoint and payload. You can see a little more here:
GitHub - kbowerma/droneTracker: particle client for tracking drone. I am able to send an update every 20 seconds with the Particle Photon now only when I am moving. I also found a really nice 500mah 3S battery on Amazon. It went from full charge to 10% in 3.5 hours with a LM7805 to power the Photon, GPS, accelerometer. The tail lights / buzzer will power directly off the 12V battery via a Mosfet. I think I can get more out of the battery if I switch to a buck converter.