On my APM2 when powering via LiPo, GPS-Lock is sometimes present after about 30 Minutes, and sometimes never.
I can get GPS-Lock (in about 2 Minutes) only when USB is connected. This is even working when connected via LiPo and USB together. I have tried many powering possibilities: UBEC in output with jumper set - BEC from ESC in output with JP1 set - UBEC in input and BEC in output with jumper on and off, nothing helped. Both blue LEDs are blinking.
I can´t use my APM anymore without GPS. It is only two weeks old, without any crash or something. On one day it is not working anymore.
Maybe my GPS is defective?
I am very grateful for any help.
Greetings from Germany
Michael
Replies
Ah, a Hexcopter! Thank you for the photos!
I suggest another experiment: Simplify the test - move the APM, UBEC, battery off the copter, if possible.
Battery ---> UBEC ----> APM on a separate board/card...if possible. This should work and also allow you to connect to the PC to the APM. This will also eliminate interference from the ESCs. Try to take the test outside the house/building/apartment (open sky) to give the GPS the best chance to sync/lock.
If success (repeat many times) add parts, one at a time, to observe interactions (if any).
If a problem still, try this: MainsAC---[5VDC supply]----> APM. Observe the result. If good, add parts as above.
The copter is a complex system with many connections. As Remi suggests, interaction is possible. We need to simplify the system to reduce variables. When simple, you will know if you can trust the APM/UBEC combination.
The output of the UBEC seems good but a little high for the APM. Is it possible to reduce the UBEC output to 5.0VDC(some have USB connectivity)? Anything more is wasted energy.
Stay confident! You will resolve this problem and we will all learn from it. ;)
-=Doug
Doug, thank you very much for you offered help.
Here is a photo of my PDB and one with the APM over it. Space between them is about 1".
- APM2 is the soldered version with GPS on the daughter board
- yes I have a voltmeter. The voltage applied to the APM2 is 5,22V from a Turnigy UBEC
- the PDB is not the one from 3DR
Once again many thanks in advance.
Is it possible to provide some photos of your set up and installation?
Is the system DIY (like mine) or did you purchase a 3DR kit?
Was the APM2 the soldered version or the kit version?
Is your GPS on the daughter board or separate (connected by cable)?
Do you have a voltmeter you can connect and measure the voltage applied to the APM2?
Are you using the 3DR power distribution board (PDB)?
Your problem certainly sounds like a power/cabling issue but we can only speculate without pictures or more information.
-=Doug
Thank you Remi. I am glad that it worked for you, and it gives me hope
I have installed a backup battery to the GPS, but it is still not perfect. More here in this thread.
NOT SOLVED
I still have that GPS-Lock problem like many others. The only reliable method to get GPS-lock is to connect USB.
My GFK-shield-solution worked for a few days. Many other solutions I tried worked for today but not tomorrow. All GPS related is not reproducable over more than one day.
Even when powering APM over external battery with UBEC on the out rail, nothing else connect, laying on a table in the garden with blue sky, I sometimes get GPS-Lock and sometimes not.
I (and I think many others) really need a reliable solution with this issue. An autopilot without GPS is absolutly useless.
Any suggestions?
SOLVED
I placed a CFK-Plate between power distribution board and the APM. Now I Have GPS-Lock after 2-3 min.
Thank you very much for your help.
This GPS-Lock-Problem drives me crazy.
Today I tested it again and placed the APM 4" outside the middle of the copter and now I get GPS-Lock even with out1 pin connected. I have nothing connected but power from UBEC on out-rail and the white cable from ESC 1. Placing it in the middle, over the power distribution board, Iget no GPS-Lock.
So I think Mike is right, it is an interfearence.
What con I do now? Can I shield it in any way?
Thank you all very much for your suggestions. But last night I found what the problem is but without a solution.
The problem is a defective out1-Pin. As soon as I connect a S-cable from any ESC to pin 1, no GPS-Lock can be established. When I additionally connect the USB, I got GPS-Lock. This cenario is reproducable, I checked it a dozen times. Of course I reflashed firmware with prior erase. And of course I cut the red and black ESC-cables. Powering is via UBEC on the out rail with JP1 set.
Anything else works great, flys perfect stable, but no GPS when pin out1 is connected.
What options do I have now?
- send it back and get a new one ( it´s only two weeks old), than I´m maybe without a copter for weeks, I´m from Germany
- solder pin out1 new (do I loose warrenty than?)
- modify firmware to get the signals from pin1 to pin7 (I fly a hexa+) But than I can never fly a octo with this APM
Any other suggestions? What can I do now?
First you should clear the memory and flash the firmware again. It could have become corrupted. If you have telemetry or any other optional sensors you should disconnect that until you get the GPS working correctly.
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