No fix on OP GPS for Revo Mini
« on: January 10, 2018, 05:26:50 pm »
Hello!

I've recently bought a Revo mini with small, black OP GPS module but i can't get a position fix.
Of course my first attempts where in my room with the drone on my desk, but then i spent about 15 minutes outside with no effect either.

Do you have any recommendations?

P.S.
I know the GPS is working becuase it says in LibrePilot it is receiving data. I've also tried the setup method with Ucenter using FTDI-USB converter which went well, but upon connecting back to the Revo it seemed to have lost all that setup because there was no effect.

f5soh

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Re: No fix on OP GPS for Revo Mini
« Reply #1 on: January 10, 2018, 06:02:50 pm »
Hi,

Those small OP GPS need good conditions to get a fix, patch antenna is small and all the components are very low cost. (+5V maximum !)
Go outside and wait the almanac to be received, this can take some time.

Quote
I've also tried the setup method with Ucenter using FTDI-USB converter which went well
Did you receive a good fix while using Ucenter ?
Manual configuration is not needed using a Revo because the GPS is configured at all times and this OP GPS do not store the (UCenter) configuration at all.

Re: No fix on OP GPS for Revo Mini
« Reply #2 on: January 10, 2018, 06:54:25 pm »
I followed these steps when configuring using Ucenter



It is Painless360's video but it's about the same what's in the LibrePilot's documentation pages.

As in video, I had at first many NMEA messages in Packet Console, and then UBX after configuration.
When in LibrePilot System->Data Objects->GPSSatellites->SatsInView I have about 5-6. I've tried lowering the MinSatellites in GPSSetting but it wouldn't work.
If I understood you correctly, it is only a matter of time then?

f5soh

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  • 4220
    • LibrePilot
Re: No fix on OP GPS for Revo Mini
« Reply #3 on: January 10, 2018, 07:17:51 pm »
There is nothing needed using UCenter since you use a revo board.
Ucenter is only needed for CC3D as described in Wiki page.
Even if you change something in UCenter into the small OP GPS the configuration is erased by the Revo or simply lost after some time when the capacitor is discharged. This small OP GPS do not have memory for config storage and in fact, cannot be used with a CC3D.

Prerequisites for a green GPS alarm is a number of sats used above the value set (default 7) and also a PDOP bellow the value set (default 3.5).
See this page, related to GPS setup using a Revo.