Compass Calibration Guide

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 Mavic to fly out of control.

What is Magnetic Inclination and Deviation?
Magnetic deviation is a horizontal variation that comes from the Mavic 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 Mavic 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 Mavic 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 Mavic 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 Mavic 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 Mavic 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 Mavic turns during flight, the reading is smooth and linear.

When Should I Calibrate?
You do not need to calibrate before every flight and in some cases you definitely should not calibrate. That doesn't mean you shouldn't ever bother doing it. It only takes one time for it to go very wrong. The most important aspect of compass calibration is making sure the magnetic "neighborhood" around your Mavic is consistent between calibration and during flight.

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 / new firmware installed.
    Location change (greater than ~100 miles).
    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 metallic (ferrous) objects nearby or you're not sure.

  • Pre-Calibration Checklist
    Everything used in flight should be powered during calibration, e.g. GoPro, tracker, etc.
    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. Calibrate on a level surface if possible.
    A cardboard box is a good idea to get it off the ground and level.

  • How to Calibrate
    Power up your Mavic and accessories as normal.
    Wait until your Mavic is ready to fly.
    Select CALIBRATE under AIRCRAFT STATUS | COMPASS. Click OK.
    Confirm solid yellow rear lights.
    Pick up the Mavic and turn it smoothly and steadily a full 360 degrees until the lights turn solid green.
    Point the front of the Mavic 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.

(source 04-11-2016 - phantompilots.com)