UP501 Fix Time?? Possible Dead Unit?

[coug67]

I received my UP501 breakout from Ada last Thursday, and I was excited to get started, but I seem to be having some serious issues getting a position fix. I can communicate with the GPS fine using my Netduino+. It will read back time (since reset) and I can set which NMEA strings I want to receive, baudrate, and update frequency, but it never seems to lock and start feeding position data. I have been fiddling with it consistently for the last 4 nights thinking I was missing something. I was able to get a lock once or twice (out of a couple of hundred tries), but nothing consistent. I initially tried using my own library (based on the Ada sample sketch and wiring description), and then I moved to the GPS library from codeplex. No luck either way. I live in the country away from the city radio noise. I have tried the unit both indoors next to a window and outdoors with clear skies. I even thought I was being too impatient, so tonight I let it try to fix for 25 minutes one time and then 45 minutes another. Still no luck. I have read online that "GPS modules typically either work or they don't." At this point it seem to be the latter, but I am confused since it still responds to command strings appropriately and sends an acknowledgement in return. Right now it's not doing me much good other than acting as a really fancy 1-second stopwatch based on the returned NMEA string. Is there something I should be checking? I am new to these modules, but I assume the 34s cold TTFF means I should have valid data in less than a minute. Am I misunderstanding? Any guidance would be very much appreciated.

[adafruit]

check that you have good clean power? noisy power supplies make the radio less sensitive.

[coug67]

I am running off the 3.3v regulated supply from the n+ board which is fed from the usb on my computer. Can't get too much cleaner. Even unplugged the comp and ran on battery. No difference.

[adafruit]

its unlikely its the module but we can replace it if you think that would help - email support@adafruit with a link to this thread

[coug67]

I'm not necessarily gunning for a replacement. I've been very pleased with the quality of the items I've ordered so far, and I'm certainly not trying to raise a fuss. It seems that I've covered the immediately obvious troubleshooting steps, and I just don't know where to go next. Only looking for some guidance....

[adafruit]

tell you what, lets try the slightly-newer Adafruit Ultimate GPS Module - email support@adafruit and ask for one of those to replace the UP501. I'd be interested to hear if it works better

[coug67]

I submitted a support e-mail as you suggested, and they've already processed the replacement. I can't thank you enough for the quick response and the great support!

Thank you!!
Jason

[coug67]

I received the Ultimate GPS yesterday and started right in with it. Initially, it got a fix within about 2 minutes, then I had similar issues; it would eventually get a fix, but very slow (30+ minutes). Today, I went to the local Shack and got a battery for the unit. I plugged it in, and within about minute I had a fix. I unplugged my N+ to see if it was a fluke. When I plugged it back in, it had a fix faster than I could restart my VS debugger. I tried 3-4 more times, and every time it has picked up a fix within seconds. I retried the UP501, and never did get a fix, but this new board is amazing. Planning on using it with a homebrew quadcopter, and this has brought back some confidence that it really is possible. Can't wait to press forward! Thank you again for the support. -- Jason