Hoverfly Finally gave the GPS board a try...

[Benjamin Rowland]

So I finally gave the Hoverfly GPS board a try today. I don't have a mast for the GPS sensor yet, so I put it on the front boom. Is raising the GPS sensor necessary if I'm getting the blue LED representing a good lock? I know it is shown on a mast in the manual.

I went through the manual and followed all of the other recommendations and calibrations. My test flight resulted in a copter taking a large circle around the position I hoped it to hold.

Should I go ahead and get the components for an external magnetometer? Has anyone seen improvements with the external mag? Bart saw improvements with raising the entire board up and has a kit for doing so. My battery tray is in the way right now, so that may not be an option for me. My ESCs are closer to the board than recommended at the moment.

 

[Webheadfred]

I'm going through all this now. I had my antenna on the main body adjacent to the HFP and a clear view of the sky. I had Issues with it sometimes taking 3-6 minutes to acquire and then sometimes it would acquire in a few seconds. I built a bracket out of aluminum and I get a blu lock nearly every time within 15 seconds so I can say it helps to be elevated. The circling, well I think I've finally tamed that by getting the wiring harness squared away. I have an external magnetometer I used on my X8 but haven't needed it on the HEX so far. I know with the external, you need to have it aligned as close as possible to forward for best results.

 

[Kristian_Elev8Pictures]

So I finally gave the Hoverfly GPS board a try today. I don't have a mast for the GPS sensor yet, so I put it on the front boom. Is raising the GPS sensor necessary if I'm getting the blue LED representing a good lock? I know it is shown on a mast in the manual.

I went through the manual and followed all of the other recommendations and calibrations. My test flight resulted in a copter taking a large circle around the position I hoped it to hold.

Should I go ahead and get the components for an external magnetometer? Has anyone seen improvements with the external mag? Bart saw improvements with raising the entire board up and has a kit for doing so. My battery tray is in the way right now, so that may not be an option for me. My ESCs are closer to the board than recommended at the moment.

Ben, let me know how the GPS worksout for ya. I'm hesitant on getting the GPS board, but would like it for a back-up.

 

[yeehaanow]

The GPS antenna should be fine on the boom. It's the compass that is the problem. For some reason I've had no luck with the external compass or the internal one. I can see them both showing the heading correctly on the ground, but in the air they will both give me problems. I had it working on my hexa great, with old firmware, but since moving to the CS8 the GPS has not worked and led to a dangerous flyaway once. (went into failsafe but wanted to return to somebody else's home.)
I was at a ski resort on the side of a mountain this winter and could not arm because the GPS board wasn't working. I took it off and haven't bothered since.
It's a great safety feature to have Return to home, and it was working nicely for me until it went on the octo.
If it's circling, sometimes turning the compass will solve the problem. Of course you'll need an external one to do that.
Good luck.

 

[tahoelight]

I just gave the GPS another try today. I have an external Mag. on an aluminum mast with the front of the mag facing exactly forward and the GPS antenna on the same mast. For kicks, I went through the same calibration process I use for an FPV quad I have with NAZA. Same two circles with it flat and with it vertical. When I turn on the HFP GPS it immediately shows instability and started circling. Return to home takes a scary arc to return. This is in contrast to the naza that has always held within a couple meters with very little toilet bowl effect if at all and return to home is always smooth and controlled. I let my 10 year old fly the naza with confidence, I would never let him touch the HFP do to inconsistent GPS functionality. I do plan to go through a more rigorous process out in the middle of a field again, but so far even with the 4.8 I am not impressed. Sorry HF, GPS is not ready yet...... HFP manual flight is still King.

 

[DucktileMedia]

I dont know what it is that they cant figure out. It's embarrassing the Chinese can do it and we cant. I recently took my GPS off as 30-40' was just too much to use it. Also by the time it established sats, I would normally be done flying. However, when using it as RTH, it did work very smoothly and showed no signs of any erratic behavior. That was the only reason I kept it on there. But due to the fact it took so long to acquire satellites, and it was frustrating to see the light under my done for the gps, I basically canned it. I too wish they could make a nice DJI like enclosure and a unit that worked without all these issues. I will also add that Hoverfly's AL is king in my book too, not just manual.

 

[Bowley]

I dont know what it is that they cant figure out. It's embarrassing the Chinese can do it and we cant. I recently took my GPS off as 30-40' was just too much to use it. Also by the time it established sats, I would normally be done flying. However, when using it as RTH, it did work very smoothly and showed no signs of any erratic behavior. That was the only reason I kept it on there. But due to the fact it took so long to acquire satellites, and it was frustrating to see the light under my done for the gps, I basically canned it. I too wish they could make a nice DJI like enclosure and a unit that worked without all these issues. I will also add that Hoverfly's AL is king in my book too, not just manual.

Not just the Chinese Yuri, Ardupilot have got pretty good performing GPS and it actually has GPS Sensor and magnetometer installed on the main board.

 

[JZSlenker]

Do you guys have ferrous metal on your birds? Is your GPS amtenna mounted higher than everything else (10cm higher as shown in the manual) We get good GPS results. We don't need the external mag. We had problems initially with it but once we got rid of any ferrous fasteners, brackets etc we've been getting good results and with the latest firmware it's pretty rock solid. Good mag reading is key to good GPS performance!

Another thought, are you calibrating your mags fully flight ready? (Camera mounted, VTX, Gimbal turned ON) All flight batteries connected? Everything powered up? All that stuff effects the magnetic accuracy and needs to be corrected for. Are you calibrating to magnetic north or true north ( this varies by geologic location ) - use magnetic north.

Just some thoughts.

 

[Bartman]

Ben,

That kit I linked you to should eliminate the need for the external magnetometer and the mast. Good clean wiring runs with the heavy wires twisted (even loosely helps) is always a good idea though.

If you watch the videos with the guys (AL's got one) using mag field sensors, the fields don't extend very far from the wires. The 2" lift my kit provides gets the magnetometer away from the bundled masses of wires and the GPS mount puts the antenna in a convenient spot. I've asked Al about mounting the antenna and he's pretty much told me it can go anywhere. I had it velcroed to the top of the GPS board at one point.

I'm also building with almost all stainless steel fasteners at this point although I'm less convinced that that is much of a help.

Bart

 

[Bartman]

FWIW, of the boards I've flown, the NAZA has an uncanny ability to do the GPS position-hold trick best. Mikrokopter has the ability to control the gain from the radio so it can be tweaked for the outside conditions and it does pretty well. Hoverfly is just cracking the code open on GPS controls, their latest software update was their best so far and a big improvement over the older firmwares so it's not unreasonable to assume they will make further tweaks and continue to improve GPS performance. Arducopter seems to be making big strides as well but we don't have very many hardcore users to really report on it.

Bart

 

[Bowley]

FWIW, of the boards I've flown, the NAZA has an uncanny ability to do the GPS position-hold trick best. Mikrokopter has the ability to control the gain from the radio so it can be tweaked for the outside conditions and it does pretty well. Hoverfly is just cracking the code open on GPS controls, their latest software update was their best so far and a big improvement over the older firmwares so it's not unreasonable to assume they will make further tweaks and continue to improve GPS performance. Arducopter seems to be making big strides as well but we don't have very many hardcore users to really report on it.

Bart

I would lay odds on 80% of Ardupilots are lying on shelves packed away in boxes, drawers etc. Thats where mine ended up when I discovered it was a bit more complex in setup than most FC's.
My APM2 did eventually see the light of day again and I began to get my head around it, Its still on a small quad testbed right now but I have grander plans for it as it earns my confidence.
Its a fun unit to mess around with and I'm looking forward to using some of its features beyond basic Pos'n/Alt Holds.

 

[Bartman]

and that is where the strength of the HF PRO puts it back in front, it's just so easy to set up and it flies perfect.

 

[Bowley]

and that is where the strength of the HF PRO puts it back in front, it's just so easy to set up and it flies perfect.

Can't argue with that, I have a HF Pro on an X650, X8, Flies like a dream, cant put my finger on what way it feels good, it just feels right.
I started out flying SRH and maybe it just feels more like a stable Heli to me, smoother, with the yaw rate in better balance with roll.

Its horses for courses though, some applications suit the APM or other more autonomous featured FC's and some require smoothness.

 

[vispaaja]

My Naza had the same problem, I found out that rotating the GPS sensor 15-30 degrees CW eliminated the "toilet bowl" effect.. I don't know if this works with Hoverfly, but that's one possible solution.

 

[Bartman]

My Naza had the same problem, I found out that rotating the GPS sensor 15-30 degrees CW eliminated the "toilet bowl" effect.. I don't know if this works with Hoverfly, but that's one possible solution.

The NAZA has to be manually corrected for magnetic declination (the difference between mag North and true North), Hoverfly has the world declination database programmed into the GPS board so it does the correction automatically.

 

[JZSlenker]

Bart, have you checked your stainless steel fasteners? Just because its SS doesn't necessarily mean it doesn't have a ferrous core. You can have magnetic SS. I've switched our builds to all aluminum.

Our center plates are aluminum too, perhaps that contributed to such good mag readings. All the wiring is under aluminum plates.


If you are getting circling in PH, then you have mag interference, not a GPS issue.

 

[Bartman]

it's 18-8 which is the less ferrous of the variants and my wiring is almost entirely outboard of the center frame. to date i haven't had a SS fastener with observable magnetic properties. it was actually Ben that first posted this and we've been discussing it from there.

what does having the wiring under aluminum do for you? does aluminum block magnetic fields or interference somehow?

 

[Benjamin Rowland]

Right now, raising the board with Bart's kit sounds like a good idea. I'll have to relocate the battery tray to do so. Another option that I'm looking at is shielding the board from EMI better. Maybe a blank circuit board down below would help (I got that idea from here).

 

[Bartman]

Right now, raising the board with Bart's kit sounds like a good idea. I'll have to relocate the battery tray to do so. Another option that I'm looking at is shielding the board from EMI better. Maybe a blank circuit board down below would help (I got that idea from here).

Ben,

I'm not 100% sure about this but I believe the shield will help prevent the GPS antenna from being subject to RF interference but it won't help with the issue of magnetic interference. TO know if you have a mag interference issue, watch the heli when it's flying with the GPS board attached. If the mag reference is checked under the Pro Info tab, and if there is magnetic interference, the heli will be unstable in yaw as you're flying around in manual or auto-level mode. GPS performance will be weak as well.

 

[Mactadpole]

Some things need to be revisited with this GPS setup. All this talk about raising this, pointing that magnetic north, non-ferrous fasteners, etc. just doesn't make sense. My MK boards sit on top of one another a few centimeters apart with a 8 bl-ctrl's (esc's) sitting a few centimeters below in a tight square around the boards, and I have a mix of SS and steel screws. It always gets at least 6 satellites in less than 30 sec. I never get toilet bowl and my position hold is pretty much within a meter. Sorry, using GPS and mag is nothing new on mr's. I don't have the solution but know and have experienced that others do.