I went to fly this morning, and my mx20 was showing zero satellites. So I let it sit for a couple minutes, and still nothing. So I hooked up MK Tool and sure enough, the GPS is there and powered up, and just isn’t getting anything. I even tried re-flashing the Navi board’s firmware, but still nothing. All the lights are on, but it just can’t see a single satellite. I don’t see any errors, but I couldn’t start the motors because I have the “don’t start without a GPS fix" setting in my flight control. Any clues where to start? It was working just fine yesterday.
Hmm. That doesn't look good. There doesn't appear to be a solar storm in progress, so the evidence suggests that the GPS board has died. Do you happen to have a spare one (even installed on another copter) that you could use for comparison -- or even a hand-held or vehicle mounted GPS just to make sure that there's no issues with GPS reception in your area? Can't imagine what would cause a black out of the GPS signals -- although GPS jammers do do that.... Andy.
I always look at what I recently did and see if anything I recently did could have caused the issue. I know you moved your nav and GPS directly above your flight control board. Did you make custom cables? Also could your GPS battery be dead?
Dave, you may be right. In the MK Wiki, it says (http://www.mikrokopter.de/ucwiki/en/MKGPS) During the first start-up, the NaviCtrl will build a complete Almanac/Index. This contains satellite positions and paths. A complete cycle to build this Almanac takes 12.5 minutes. It also says If the fix takes a longer time, it could be that the small battery on the GPS board is too weak.I’m running the U-blox diagnostic program, and I see lots of satellite activity going one at a time through the many satellites. I’ll give it its 12.5 minutes and see if it finds anything.
Hmm...15 minutes of hunting for sats and still nothing. On the phone with our friends in Whitefish to see if they have any ideas.
I have exhausted everything, and I have concluded that the GPS board is snafu’d. I have no idea what happened...it was literally doing beautifully in flight yesterday, made an easy landing, packed it in the car, and drove home. This morning took it out, and nothing. And what’s weird is everything else is working fine, and there are no errors anywhere. I’m stumped. I’m going to replace it with my backup and see if that works. And I’ll measure the voltage of the little battery, too, but it’s unlikely that the battery is the culprit unless it’s completely gone rogue. The only theory I have involves the NSA. But I can’t talk about it.
Yeah, when hardware goes TU, one minute it's fine, the next it's not. The little battery is, as Dave said, only used to store the ephemerides for the satellites. It gets recharged whenever the GPS board is powered up. It is not used to power the GPS itself. I seem to remember that the GPS board is fairly sensitive to static (I could be hallucinating that though), so if you were handling it wearing your nylon leotards and furry bunny slippers... Andy.
Steve, Sounds like ESD has damaged the amplifier on the antenna. This can be repaired. Greetings, Adam
That’s great. I’ll verify that the other GPS antenna I have works, and I’ll send it in. You guys are the best! Steve