I ordered a GPS Falcom FSA-03 module+breakout(assembled) for $cheap,-. This will be the main GPS system, my current one will be the Backup, working together with the T68i phone that i also have; as backup. So i have 2 GPS systems, and 2 GPRS (phone) systems. You understand i do not want to lose my payload =).
From the states i also ordered a humidity/hygro sensor, 2x temp sensor, CO sensor (carbon-monoxide), and two lightweight servo‘s. Just for the sake of science.
I also thought i could use some solar cells on my payload, to warm up the inside of the module (since it shouldnt get too cold inside, and it will). So i calculated that at 20km, there is just 1 gram of air in my payload (because of low air density). So with 6x1Watt solar cells, i would get a temperature rate of ΔT=6°C/s if you consider it as a closed system. I probably made a mistake (someone check it?). But eh, that’s a little too much, back to the drawing board.