Ok to fly without leg compass attached?

[jca]

I was getting magnetic interference continuously so I unhooked leg compass and recalibrated. Says ready to fly. Is it really dangerous to fly on only one compass? I'm going to probably get a new gps with compass ordered tomorrow but am itching to try the drone again.

 

[carpy]

I wouldn't do it. You are better off finding out what is causing the interference. Did you always have interference no matter where you took off from?

 

[carpy]

See this post, https://3drpilots.com/threads/magnetic-tray.10126/#post-115850

 

[jca]

Hey Carpy, I ordered a new gps with compass so will be using that. I might try to deguase today using a anti scaling winding I have on pipes in basement. Looks like it's ac.

 

[jca]

Well, that didn't work (degause)...guess I'll wait for new one.

 

[jca]

OK, new GPS/Compass came. I get Compass needs calibrating when starting. I tried the Mission Planner 38 to 0 thing but it looks to me like Mission planner has had a new version since the Jester Drones vid was made. Very different. Could't find compass_orient in parameters. Under initial setup there was some compass parameters but none of the numbers matched the 38 one I was looking for. It does show two compasses and number 1 is the external according to that. I'm kinda lost right now. I'm guessing I could unplug the new compass in the GPS and fly but that kinda defeats the purpose of waiting this week for the new GPS. BTW, I can see up to 16 Sats connecting indoors here with the new GPS. I just ordered the cheap one off ebay as I'm out on disability right now and money is tight.

 

[jca]

OK, update, I figured out how to get into advanced parameters. For those in the future needing this go to planner and under layout (near bottom) change it to advanced. Got the 38 to 0. Still only calibrates to about 75% then stops. Next I guess I'm going to try reversing the leads to the compass. I thought the blue (SDA) from the solo would go to the blue from the compass as a youtube vid on the compass had lead me that way but maybe it was wrong. So now I'm going to solder the white from the solo to the blue wire from the compass and the blue from the solo to the green from the compass...

 

[jca]

Yeah, switched wires on compass and it started right up. Now to charge everything and fly tomorrow.

 

[jxo]

I was getting magnetic interference continuously so I unhooked leg compass and recalibrated. Says ready to fly. Is it really dangerous to fly on only one compass? ....

This underlying question was never answered?

Have the exact same issue on one Solo. I had the Magnetic Interference block following a minor crash. Disconnected the leg compass. Did a compass calibration. Reconnected the leg compass. Did the compass calibration again. All was well for a few flights. Now get a compass error and cannot calibrate. But it does fly with the leg compass disconnected. Put in an upgraded GPS module. Got courage and flew it without the leg compass. Did about a dozen flights without a camera. No issues that I could tell. Took it to 200ft. and all controls worked fine.

What does the compass do? integral to the GPS, navigation or control? belts and suspenders? for readout purposes only?

I will degauss the compass and replace it if I can't revive it.

 

[just_bruce]

The compasses are integral to the function of the EKF that the Cube runs. Whether running without one is dangerous is somewhat subject to interpretation. There are many arguments for redundancy in aviation, but in this case there is reasoning beyond that. See, the second compass is located MUCH further from the noisy computer electronics, and thus is able to enhance the granularity of the magnetic component of the EKF.

Dangerous is a bit of a judgement call, but consider that-

1. You have no redundancy of magnetometer when flying on only the one in the Pixhawk.
2. Rejection of stray magnetics from electronics and antennas will be weakened, meaning false compass data will be harder to filter out.
3. Your magnetic component data will be less granular, degrading your EKF performance which can lead to heading drift and possibly position drift over time

 

[jxo]

... Dangerous is a bit of a judgement call...

Thanks much. Clear. Clearly more than data diagnostic output. Much, much appreciated. Clearly will reduce operational risk. With expensive Sony cameras on board-- not a risk I will run.

Embarrassed to say I forgot that I had purchased a couple of number 4 replacement legs with the compasses. I will install one and hope it clears the error. That compass connector on the mainboard is a PITA and I may have mangled it.

If that does not work, would the integrated compass in the Here GPS unit fulfill the need for the additional compass support if I can't get a leg compass to operate?

 

[just_bruce]

Thanks much. Clear. Clearly more than data diagnostic output. Much, much appreciated. Clearly will reduce operational risk. With expensive Sony cameras on board-- not a risk I will run.

Embarrassed to say I forgot that I had purchased a couple of number 4 replacement legs with the compasses. I will install one and hope it clears the error. That compass connector on the mainboard is a PITA and I may have mangled it.

If that does not work, would the integrated compass in the Here GPS unit fulfill the need for the additional compass support if I can't get a leg compass to operate?

The HERE compass is a very adequate replacement as long as you adjust the orientation parameter

 

[RichWest]

That compass connector on the mainboard is a PITA and I may have mangled it.

The Here compass uses the existing compass connection on the main board. So you are not off the hook in repairing that if damaged...

I find hemostats work well handling the click-mate tab'd connectors and others of small design...

 

[jxo]

Guys, thanks again for the advice and feedback. Your're great. Having the right tools is always a good idea; very likely there was fat finger damage to the old compass.

This village idiot forgot he had lots of B&H supplies tucked away including a new compass leg. Replaced the old one and now all good. No need to go the Here route (getting an older version to work with my stock controller would have been a challenge).