Hoverfly Hoverfly GPS, another approach

[Bartman]

Hi everyone,

I'm trying something different with my Hoverfly GPS installation. In the pics you can see I've elevated the GPS board about 2 1/2" above the PRO board and I'm using four servo wires as a temporary connection between the PRO and the GPS boards. You can also see I've put my motor wires in braided wire wrap from where they exit the CF arms to where they connect to the ESC's.

With the new firmware installed and all the calibrations redone I've got good stable flight and no wandering heading (yaw) issues that were present when the GPS was mounted as designed to the PRO board. SO maybe the elevated GPS board is helping with the magnetic interference issues. Also, the GPS board went to solid green in about 45 seconds after the first power-up with the new firmware.

The problem now is that the heli is wandering around when GPS position hold is engaged.

View attachment 8214View attachment 8215

I'll keep working on it but the elevated position of the GPS board seems to be helping. Any suggestions/comments/opinions?

THanks,
Bart

 

[Bartman]

I've got 2 1/2" standoffs on order to clean things up a bit.

Can anyone suggest a source for 12 wire ribbon cable and 2x6 end pieces? The servo connectors prevent the board from being mounted any lower than it currently is.

Thanks,
Bart

 

[S11D336B]

Bart,
What you are seeing is related to the on-board compass on the HoverflyGPS picking up EMI from your on-board electronics. We have a solution for this.
https://hoverflytech.zendesk.com/entries/22417583-external-compass-magnetometer-v4-6-and-above

Moving your HoverflyGPS board a few inches up is basically the same thing as using an external compass in terms of how it affects this issue.

Your efforts are probably better spent just using the external compass as the results will be the same (with a lot less effort).

I've got 2 1/2" standoffs on order to clean things up a bit.

Can anyone suggest a source for 12 wire ribbon cable and 2x6 end pieces? The servo connectors prevent the board from being mounted any lower than it currently is.

Thanks,
Bart

 

[Bartman]

thanks for the reply George but I'm trying to keep everything under the dome. If I can get the board to work well at about 2 1/2" then it will fit. What I don't understand is that I'm getting a quick satellite lock and I have no heading/yaw issues like I've had in the recent past. Why would the GPS PH performance still be flaky?

I've seen the external mag modification and the newer GPS board but I've wanted to see about this arrangement before going the other route.

Bart

 

[S11D336B]

You could still have compass issues. I would start by re-calibrating your compass. The current version of GPS hold also does not hold a position extremely aggressively, but it should more or less stay in the same position.

-George

thanks for the reply George but I'm trying to keep everything under the dome. If I can get the board to work well at about 2 1/2" then it will fit. What I don't understand is that I'm getting a quick satellite lock and I have no heading/yaw issues like I've had in the recent past. Why would the GPS PH performance still be flaky?

I've seen the external mag modification and the newer GPS board but I've wanted to see about this arrangement before going the other route.

Bart

 

[Bartman]

is the GPS PH something that is in the development pipeline?

 

[DucktileMedia]

Bart, I like your solution a hell of a lot more than the ext. mag. Like you said, it keeps things tidy. can you safely compare it to being installed the recommended way though, since you are using a different firmware as well right? Following closely. I dont think your setup would fit under the Crate and Barrel Onion storage container/dome.

 

[Photronix]

But you could just mount the external magnetometer under the dome 2.5 inches above the board and achieve the same result I believe.

 

[Bartman]

But you could just mount the external magnetometer under the dome 2.5 inches above the board and achieve the same result I believe.

I suppose you're right about that Al, maybe that's why you're the Pres?

I'll have to get my hands on one of those and see about that. Everything appears to be stable with things where they are, just not too much autopiloting going on by the autopilot in PH mode. I'll keep flying it and see about it getting better.

Bart

 

[Bartman]

Bart, I like your solution a hell of a lot more than the ext. mag. Like you said, it keeps things tidy. can you safely compare it to being installed the recommended way though, since you are using a different firmware as well right? Following closely. I dont think your setup would fit under the Crate and Barrel Onion storage container/dome.

no, it probably won't fit under the onion dome. You should figure it'll be at least 2 1/2" above the PRO board if you use converted servo wires like I did. with the correct terminal ends and some 12 wire ribbon cable you might be able to get them closer but too close and you're back with the interference problem. i'll play with it and see where it goes.

 

[DucktileMedia]

If your test yields good results could you please attach your GPS normally to the pro and compare on the same day same location just to verify this is what's making the change? Also, what about your idea of using carbon as a shield? If you made a plate that slipped in between the boards with a notch just big enough for the connector to fit through.

 

[Bartman]

If your test yields good results could you please attach your GPS normally to the pro and compare on the same day same location just to verify this is what's making the change? Also, what about your idea of using carbon as a shield? If you made a plate that slipped in between the boards with a notch just big enough for the connector to fit through.

i've got the carbon fiber in there right now. i can put it all together the normal way to see what changes.

i wish they'd add an adjustable GPS gain that can be assigned a slider on the radio. what's the point of a GPS PH that is admittedly weak even in light winds?

 

[DucktileMedia]

Well, if for some reason you can make the GPS hold better than 10' let me know what you do. For now, I am gonna keep it off and stay on the previous firmware as it is just too good to risk getting rid of.

 

[Razzil]

Do you have any results using it this way? (with the carbon plate between the PRO and GPS)

i've got the carbon fiber in there right now. i can put it all together the normal way to see what changes.

i wish they'd add an adjustable GPS gain that can be assigned a slider on the radio. what's the point of a GPS PH that is admittedly weak even in light winds?

 

[S11D336B]

That depends on what you use GPS hold for. I think you'll find that we don't claim accuracy better than 10' (though it may be achievable in the future).

Right now, GPS is intended to work more for failsafe situations rather than as a tool to keep your multi-rotor in exactly the same spot.

i've got the carbon fiber in there right now. i can put it all together the normal way to see what changes.

i wish they'd add an adjustable GPS gain that can be assigned a slider on the radio. what's the point of a GPS PH that is admittedly weak even in light winds?

 

[HeliFlightCenter]

Hey Bartman.
Just curious, is your copter drifting away from your set PH or is it circling around it?

 

[Bartman]

just a quick update,

I removed the carbon fiber plate from between the GPS and the PRO and it didn't make a difference. The GPS is still mounted on 2" stand-offs above the PRO and that seems to be what is making a difference in addition to bundling the wires more closely together. I also need to admit I had the GPS antenna plugged into the wrong socket on the GPS board so I'll have a better test tomorrow when I'm out flying. The heading glitching disappeared with the extended stand-offs though so there's hope.

Bart

 

[DennyR]

Silly question but did you set the declination or is that done with the firmware on HF. With DJI you need to twist the whole gps/mag unit and keep it well away from motor wires Etc. With Naza-H and WKM I get a position lock that is about 2 mtrs. max. with the tx on the ground. Check out the new DJI vids. on the Phantom. Colin Guinn has done a good job. Notice the compass is mounted low on the U/C http://www.dji-innovations.com/products/phantom/overview/

 

[Bartman]

Denny,

The Hoverfly GPS has world declination data resident in its memory so it's compensating automatically once it has a position fix. I thought about manually adjusting it but asked HF and they explained it to me.

I'm going to fly it again today and see how much better the GOS works. I know they're working on it (with position-hold having priority) and should have an update soon.

Bart

 

[Razzil]

I'd like to know your resluts. Here are few images of what I've got done.
Haven't tested yet as the Hex is current in the build process, shouldn't be too much longer.
When it was in the quad config without the carbon fiber plate, I wasn't impressed with the gps hold.
I've since gotten the Mediatek v2 GPS to go along with the build so ... figures crossed.

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