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GPS module for high altitude unmanned balloon

Posted by Overwatch on February 13, 2010 at 6:56am

Hi, we've been looking for a GPS module to use in a high altitude balloon project and we've been able to find only two units (Lassen IQ and Trimble Copernicus) that follow the DoD spec correctly. Unfortunately both of them are a pain to use.

A GPS module should refuse to operate at an altitude of 60 kft AND airspeed of more than 999 knots, but in reality most commercial GPS modules implement these two rules with an "OR" operation.

If you know of any currently marketed GPS unit (preferably with a serial interface) that either joins these two limits with a conjunction ("AND") or implements just the speed limit with no regard for altitude, please link it here.

Thanks in advance :)

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Replies

Yariv May 11, 2010 at 5:03pm

From past experience with high altitude balloons, don't use Sirf !
It got stuck at 20km (even the time stopped) and only came back to life when we got below 18km.
The uBlox LEA-5H datasheet says that it works up to 50km.
They usually don't lie in their datasheets ;-)
I intend to use a uBlox module in the next balloon I build.
MariusN April 8, 2010 at 7:57am

The discontinued chip u-Blox TIM-LP works for sure. I've flown it up to 100,000. No idea about the newer u-Blox products.
Scott Plunkett April 7, 2010 at 1:24pm

The one David mentioned is your unit...it works well and has documented flights above 60k.
David April 7, 2010 at 1:22pm

By the way, there's a relatively simple explanation for the lack of high altitude support... 65535 is an easy number to settle on as a maximum, especially given that most applications don't require more than that.
David March 4, 2010 at 1:22pm

Check out this unit from Inventek (it is mentioned on the page that Krzysztof linked to). I've seen these fly to 110k' no problem, and Inventek is capable of working with folks interested in custom firmware, in fact, they list a number of "off-the-shelf" custom builds for their modules. Responsiveness depends on the agent that you talk to when you call.

I can vouch for the validity of the page that Krzysztof provided: the gentleman who put that together is an avid high-altitude hobbyist.
T3

Krzysztof Bosak February 13, 2010 at 7:01am

http://showcase.netins.net/web/wallio/GPSrcvrsvs60kft.htm

W0RPK GPSv60KFT