I asked Paul Baker from flightaware some time ago about using this data for such a thing. He said it was too easily compromised." It works for me though.
Small computer running linux OS with results on screen, 11.23am 19/07/2018. It would be good to have a few peppered out in the never never. They can do multilateration calcs by tying in numbers ground based receivers. The blue thing is a battery powering the computer. It will run it for about 24 hours. 6000mah phone battery.
RPI Zero W $14.96
Rpi Power supply $19.95
USB otg host cable $ 5.00
Prostick rtf sir under $50
SD Card 8gb or bigger but 8 is enough. $??
Internet connection $???
400 gram empty tin can $ 0
cable fittings $ 5.00???
bit of cable $????