Compass Calibration Guide

[msinger]

Do you think that calibrate the compass again in the perfect area (dressed with my pyjama ) would be sufficient? Or did I damage it for good?

If you need to and/or want to calibrate the compass, just make sure it's done in a location that is not near any magnetic metal objects. 10 feet away from any suspect objects should be plenty.

when "compass error" appears in the Dji app, should I do it only if I'm in the good environment

In most cases, that error message is telling you the Spark is near a magnetic metal object. You should move the Spark to a different location. If the error message goes away, then there is no need to calibrate the compass.

 

[Palderic]

Thank you very much for this super quick reply.

I will do it as soon as I find the perfect location.

 

[Palderic]

I've found the perfect spot, take off all the metallic things I could have. And it works perfectly now. Thank you again!

 

[Festijn]

Why Calibrate?
Compass calibration is important to safe, controlled flight. It compensates for changing background magnetic "noise", a.k.a. magnetic inclination and deviation. Inclination and deviation that isn't corrected through compass calibration will cause inconsistencies between GPS and compass that can result in "toilet bowl effect", a swirling motion that can cause the Spark to fly out of control.

What is Magnetic Inclination and Deviation?
Magnetic deviation is a horizontal variation that comes from the Spark itself and the equipment you have installed on it as well as the magnetic makeup of the area you are flying in (again not to be confused with declination). Sometimes the deviation will be insignificant, but other times it can be big enough to cause you to lose control. Inclination is a vertical magnetic variation that shifts depending on where you are.

Warning Signs
The Spark can only detect when the compass is providing extremely poor (implausible) data. This typically occurs if you place it near a strong magnetic field or do not calibrate it properly. It will flash red and yellow lights and the Spark will indicate a compass error in the app.

IMPORTANT: The lack of a compass error does NOT mean your compass is working and calibrated properly.

Compass Interference
You can view the current compass interference in the "Main Controller Settings" --> "Advanced Settings" --> "Sensors" section of DJI GO. The colored bars should be in the green (Excellent) range when the Spark is in a location that is away from magnetic influences. If the bars are in the red (Poor) range or close to it, move the Spark to a different location and check again. If the compass interference is still in the red (Poor) range or close to it, the compass could need calibrated or it could be magnetized/damaged.

IMPORTANT: A good compass interference value does NOT mean your compass is working and calibrated properly. For example, if you calibrate next to some rebar, the compass interference might report good values may still be OK until you fly away from the rebar.

What Does Calibration Actually Do?
Calibration measures the magnetic fingerprint of the surrounding area. By turning the compass 360 degrees, the Spark can see where the compass reading doesn't smoothly increase or decrease. It uses this information to build an adaption table so that when the Spark

IMPORTANT: The ideal place to calibrate is an open field with nothing metallic in a 20 ft radius. Keep away from drainage pipes, irrigation systems, rocks, etc.

• DO Calibrate
  • Compass interference values are out of whack or compass error is reported (check area first).
  • Circling in flight (also check for other possible causes).
  • New equipment added or removed.
  • Significant change in terrain (e.g. to/from mountains).
  • If you just degaussed your compass (BTW, don't degauss unless instructed).

• DO NOT Calibrate
  • If near concrete, buildings, and hidden or overhead power lines/pipes/etc.
  • If you're indoors, on a paved surface, on a stone surface, on the beach, on a boat, on a balcony, near a car, near speakers, etc.
  • If there are magnetic metallic objects nearby or you're not sure

• Pre-Calibration Checklist
  • Everything used in flight should be powered during calibration (e.g. GPS tracker).
  • Remove all metal from within 10 ft radius (e.g. watch, phone, ring, belt, coins, controller).
  • Calibrate on grass or dirt and not on concrete/asphalt (unless you know the concrete/asphalt does not contain rebar).
  • Calibrate on a level surface if possible.

• How to Calibrate
  • Power up your Spark and accessories as normal.
  • Wait until your Spark is ready to fly.
  • Select CALIBRATE under AIRCRAFT STATUS | COMPASS. Click OK.
  • Confirm solid yellow rear lights.
  • Pick up the Spark and turn it smoothly and steadily a full 360 degrees until the lights turn solid green.
  • Point the front of the Spark straight down and repeat until the lights turn off and resume normal flashing.
    Note: Don't be concerned if your gimbal reacts poorly to being face down, keep turning as normal.

If for any reason you do not complete any of the above steps smoothly and evenly, restart the process.

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Note: A lot of this information was copied over from ianwood's thread in the Phantom Pilots forum.

 

[Festijn]

Do you also need to calibrate when you add a lensfilter of 67gram? Both IMU and compass?

 

[Dronason]

You mean 0.67 gr filter (polarpro)? I don't see a reason for that.

Sent from my SM-G950F using SparkPilots Spark Forum mobile app

 

[msinger]

Do you also need to calibrate when you add a lensfilter of 67gram? Both IMU and compass?

No, you do not need to do a compass and/or IMU calibration after installing a filter.

 

[JeyTea]

I had a compass error inflight for the first time..nothing magnetical near to the Spark..should I calibrate the compass now? Don't know what causes it, but the Spark behave very strange..was almost a Flyaway..on the flight after it everything went well but now I am concerned...should I do a recalibration? Never had done one till now

 

[Dronason]

Yes, you should but as describe by @msinger in this thread, at a clean location.

Compass calibration are not really needed often at all. Important is to have a good one. First sign is that your Spark fly with a small angle. If the angle is too big then the Spark will have a conflict between orientation given by the Spark and movement controlled by the GPS. Second there will be the toilet bowl effect and fly away if really poor. Also if you move at some really distant place where the magnetic North is not at same direction as where you calibrate.

Cheap drone with only GPS control (no Glonass satellites), poor firmware and mandatory to do always a compass before any takeoff (you do it badly a day or another) result in toilet bowl effect very easily, I had it several time. This guys show it nicely in his video:

When Spark is hovering, its flight controller will try to make a position correction due to wind drift to bring it where the GPS say it should be. So it will calculate the angle it should adjust the thrust of motors to go to that position but with a compass error (angle difference between the orientation reported by the compass and the real orientation the Spark will move and will be reported by GPS) it will arrive at a wrong position. The next iteration done by the flight controller will also result in an error and it can to start turning around the expected position. Depending on several factors, either it converge finally to correct position or it start to circle with more and more large distance from the correct position.
In the past, the correction could be done by rotation physically the compass on the drone. Now there are what is called compass calibration. It will allow the Spark to define what is the angle between magnetic North and the Spark structure. Normally the thrust angle difference with the structure is expected negligible. In fact it is the total error between compass North indication and the thrust angle that is important. This is illustrated here:

When the compass angle error is reasonable, it will be not noticeable. If the angle error is larger, you will get instability in hovering (small toilet bowl effect) or even fly away (large toilet bowl effect). The Spark will detect at some point the compass issue and will go for manual control. If it is fare away or you didn't notice that it is no more control under the GPS or there is a lot of wind, it will be difficult to control and bring it back.
Go4 app indication of compass error at low altitude usually means that Spark is near some metallic stuff. It doesn't mean you must recalibrated but that it should move it away.

• Take off at another location
• Take off on some plastic box
• Move away from car
• Take some altitude
• ...

As soon you are at some altitude, there is no more interference with metallic part at ground level.
If you get a compass error at some altitude, it means that you compas really need a good calibration.
Practice of manual mode (ATTI, no GPS) is important so you are ready if this happens.

 

[Louieaw]

I am new to droning and have only flown my spark about 6 times, and timidly at that. I have noticed a couple of things regarding the compass/home point and would greatly appreciate any advice. 1. The only way I can see to calibrate the compass on the app it to click on the link on the Aircraft Status screen. My problem is that the calibrate link doesn't always appear. [When it does appear it is not on the compass line but the one below: IMU (though it takes me to a screen where I can toggle between both). On videos I have seen it appears on the compass line.] Is there any reason why the link to calibrate would appear some times and not others? Does it mean it doesn't want me to calibrate the compass? I have not been able to find anything in the manual or tutorials. (In these screenshots the link did appear)
Any help greatly appreciated thank you .

 

[msinger]

Does it mean it doesn't want me to calibrate the compass?

No.

DJI made this change a few months ago, but never mentioned why it was changed. I'm thinking they don't always show it in the aircraft status section since many people think the DJI GO app is prompting the pilot to calibrate the compass.

 

[Louieaw]

Thank you, much appreciated. Can you please confirm that on those occasions when the calibrate link doesn't appear on the aircraft status screen, it is not possible to calibrate the compass - I certainly haven't been able to find a way.

 

[msinger]

You can calibrate the compass from the following section of DJI GO at anytime:

 

[Louieaw]

That is tremendous help msinger. Thank you so much for going to that trouble. I will get into the app now.

 

[Louieaw]

Yes! thank you again.