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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Thanks Krzysztof!
Do you have any recommendations for one on this list that works well with the ArduPilot?
No, just found it on the Internet. I trust this data. Unfortunately I am not aware of +20kft GPS with 3-6Hz update rate.
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.
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.
The one David mentioned is your unit...it works well and has documented flights above 60k.
Exactly: it's 2^16, a common memory block size that's easy to work with and results in a number that is greater than the number of feet that nearly all consumer GPS applications' altitude will ever hit. This results in a rather loose implementation of the GPS spec (OR logic rather than AND). Using the high-speed telemetry link that my team flew on high-altitude balloons, 65535 was commonly the last altitude seen when we tested limited receivers.
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.
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.
Thanks, in the end we went with the Copernicus - a bit older and a royal pain in the butt to work with, but known to operate well in near space.

Hi there,

Appreciate I'm a bit late to the party but for anyone looking for high altitude GPS modules current information is as follows. Currently there are four GPS modules known to work at high altitudes ( >18km) they use an AND statement rather than an OR statement for their adhereance to the the COCOM limits. These have been launched by members of the high altitude balloon community.

  • uBlox 6 based modules (LEA-6, NEO-6, MAX-6). This module is the sucessor to the uBlox 5 and works fine up to 50,000 meters (164,000 feet) in flight mode. There are a number of commercial modules this is used in like Radionova M10382 and the later versions of the Falcom FSA03 (now discontinued). The chips is a surface mount module but there are a number of sites selling breakouts etc.Personally I run HAB Supplies and sell modules based on the MAX-6 chip. This module has been flown in the top three world record highest amateur balloon flights (currently 43,721meters).
  • uBlox4/5 modules. These are now end of life but were more advanced than the Lassen IQ modules. They aquire locks much faster. These are still availble and are used in the Sparkfun GS406 and the discontinued Falcom FSA03's.
  • Lassen IQ. This is a 12 channel 1 Hz GPS module which has been used in many flights. It is end of life but modules are available on E-Bay. You will need an external antenna for this and a breakout board as the connector on the bottom is very small.
  • Trimble Copernicus. As noted must be configured in AIR mode but then works to 50,000meters.

Known Problem GPS Modules :

  • Anything with a SiRF III Chipset. This includes the Inventek ISMF2 "High Altitude" version, although intended for high altitude use it will stop at 135,000 feet. Given the newer latex balloons can exceed this I can't recommend this module. GM862/GS405
  • Venus 634FLPx - New firmwares should allow operation > 10km currently not tested.
  • Garmin GPS20

Also please note the following : Cheap keyring cameras i.e AEE MDS91S etc will act as very effective GPS jammers in close proximity to your GPS Chip. 

Although we are advised the MediaTek MT3339 GPS modules are meant to work at high altitude the one launch done with one topped out at 10km (GlobalTop GPS-FGPMMOPA6C). This may have been a configuration error we don't have full information on these modules at this time.

Hope this helps to anyone looking for high altitude capable GPS modules. If you need further information there is a wealth of coding examples and advice over at the UKHAS Website.



This is even later, but I just wanted to add a quick comment about the Venus 634FLPx.  I've personally flown this unit to 63k feet and can verify that it worked without problems.  This is a version of the board that Sparkfun sells that is at least 2 years old, so pretty much any 634/638 board should work without issue.

For more data points, see the Trackuino project which was built using the Venus 634FLPx.

From what Skytraq (the manufacturer's of the Venus 634FLPx) has told me, the SUP500F/R and the S1315F should also work > 10km (I haven't verified this yet).

Just to provide an additional data point.


Brad (KF7FER)

PS Did you look at the MTK3339 datasheets?  It seems to get high altitude support it appears you'll need to use some non-standard binary mode (not NMEA183) called One Sentence for this to work.  I had high hopes for this unit but anymore I'm not so sure. 

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