What GPS to use for high altitudes

Hi Im building a high altitude balloon (flying as high as 40 km). I have seen that many recommend ublox as a gps. Now I wonder which ublox gps to buy. I found a relatively cheap one Here. Will that one work?

I found this article that may help.

And there is this, a more integrated version of a more advanced Ublox;

Ublox 7

The Ubloxes should work at that altitude, but who knows for sure what firmware is loaded on a cheap GPS off eBay ?

Given the cost of a high a altitude balloon flight, the payload, balloon itself, gas, radio gear, chase recovery, etc, it might not be a good idea to start by going cheap on the critical part, the electronics.

Without the electronics working and relaible you wont be able to track the balloon or find it when it eventually lands.

I will probably only use that gps for logging data, not tracking, so it will not be that critical... But In principal both should work out?

So the one you posted does seem interesting. As it is only 6 pounds i think I might just give it a try.

What confuses me about that one however is that the connections are not labeled at all... Which is Rx and Tx? (Ground and Vcc are obvious)

But In principal both should work out?

Make sure you check the environmental operating specs.

(sp. ""principle")

bestanamnetnogonsin: What confuses me about that one however is that the connections are not labeled at all... Which is Rx and Tx? (Ground and Vcc are obvious)

Until you get it how can you be sure they are not labelled ?

And given the skill level required to put it all together into a working logger, coming up with a way of working out which of the two wires is RX and TX ought to be easy.

bestanamnetnogonsin: I will probably only use that gps for logging data, not tracking, so it will not be that critical... But In principal both should work out?

In principle, using the GPS for logging during a test flight is a reasonable plan. If the GPS works throughout a flight, do let every one know.

You will need an Arduino or similar to drive the GPS, the UKHAS site linked to earlier has the required setup string you need to send the Ublox to put it in high altitude flight mode.