Ava High Altitude Balloon Project

EDIT2 : These are now in stock and available at HAB Supplies

EDIT : The extremely long long times were very odd and I’m not sure something environmental wasn’t going on. I’ve subsequently tested both modules repeatedly and from cold inside (in a window) they are getting 3D locks from cold in sub 40 seconds consistently.

Finally the long awaited sample of the new offering from uBlox landed on my desk. The MAX-7C is the latest module from uBlox offering better power usage and performance. Additionally the MAX-7C can run from 1.65v to 3.6v meaning it can be used on both 1.8v and 3.3v boards with no problems. Additionally the UAV/RC crowd will love the 10Hz updates.

Downsides ? No more TCXO meaning lock times may be slower. I set up a testing environment mounting the MAX7 on a breakout with a chip antenna :

Along side was a MAX6Q for comparison. Firstly I ran the MAX6Q noting the power usage from 3.3v :

Aquiring 60mA (Average over 5 mins no lock)
Tracking 44mA (Average over 20 mins)
Cyclic      15mA (Average over 15 mins)

Its worth noting the GPS did seem to take an extremely long time to lock that evening, normally its nothing like 5 mins.

Now the MAX7 :

Aquiring 22mA (Average over 20 mins no lock)
Tracking 17mA (Average over 10 mins)
Cyclic    6mA (Average over 10 mins)

Conclusion : In the very brief test I did the MAX7 did take longer to get a lock than the MAX6, however once it was locked the performance was very similar, I couldn’t tell any difference. However the big difference is the power usage. Reducing the usage in cyclic by over 50% is a massive improvement. I can’t wait to run test one of these on a the PAVA boards.

Additionally I tested 10Hz mode which seems to be pretty good, however further testing is needed. Once I’m confident with it I’ll have these for sale on http://ava.upuaut.net/store