I see so many posts about compass errors and crashes due to compass errors. I am starting to wonder if some folks aren't using these things right.

I had read a post from an engineer explaining the sensor (IMU and compass) readings and what is a normal range. I always check as part of my pre-flight checklist. Apparently, normal compass readings are between 1450 and 1600.

I have calibrated my compass locally in the middle of a football field at least ten feet or more from where I emptied my pockets, took off my watch and phone. I have had no trouble with the calibration process. Before takeoff it generally reads around 1450 to 1480.

Last week I went from Atlanta to Ocean City, MD. I did a compass calibration in a playground area at least 20 feet from the equipment. The sensor readings were about 1500. I made some beautiful flights and had a good time.

Now I am back in Atlanta. I went to fly this morning. I checked the sensor readings and they were a bit over 1500. That made me realize that I had not recalibrated after driving 600 miles.

As it was still in the normal range, and I was in front of my house and did not want to calibrate on the street, I decided to take off. I kept the bird low for a bit and slowly raised height and distance. I had three flights of about 1500 meters each without a problem in GPS mode and using RTH after losing signal.

I will re-calibrate next time I go flying as it will be from a park or field. I am wondering if people who report compass problems are checking the sensors before flying to see if the compass readings are within the normal range and also keeping track of their readings so they would be alerted and question why the readings they usually get are significantly different even though they fall within the normal range. Perhaps they would catch some of these problems a lot earlier.

Actually if the compass is between 1,000-2,000 your ok.
I've actually forgotten to calibrate when I traveled about 400 miles away and I didn't notice anything. But I would not recommend doing that.

DJI-Ken Posted at 2016-7-1 05:40
Actually if the compass is between 1,000-2,000 your ok.
I've actually forgotten to calibrate when I  ...

I have never had readings below 1400. What do those readings mean anyway?

I have had my Phantom 3 professional for about a year now. I have had 10's of flights taking off from my back garden. I regularly reset the Imu and almost always calibrate the compass.
About a month or so ago I did the same calibration as I had many many times before in the same spot as always. At  about a mile away The drone stated slanting and said compass error on the screen. At first I
Thought maybe a bird had attacked it. I then lost signal and the drone. After a 4 hour search thankfully a postman told me where he had seen my drone( about 1/4 mile from where I last had control). Luckily it had hit a tree
Just before it would have hit the ground or worse on a main road.  I was flying over fields at about 400ft with no power lines near by. I had made the same flight many time before and also have been very strict about
My pre-flight set up as it is my pride and joy.  Sadly I have lost confidence and not flown since as I cannot find a definitive answer as to what the problem is (i.e. Software or firmware error, etc). I can't even put it down to a
One off freak thing as so many others seem to have had the same problem.

So today I flew a mile away over a busy California tech area.  The signal was rock steady and perfect.  My longest flight so far.  I was super excited.  I landed her and then decided to have a little more local fun.  Bt it up about 30 feet and started doing some quick flying around the parking lot when I got a compass error and it got all wonky flying.  I got super lucky and was able to bring it in for a safe landing.  

Why did I get a two mile round trip followed by a 1000 foot vertical ascent and descent and land only to have it go nuts on me when attempting another take off?  I am afraid to fly too far now...

My son just lost his companies Phantom3 this week due to compass error. He said it was up maybe 50' then just had a mind of its own, hit a tree then to Earth...
RB

Not sure if it relevant or related but the gimbal has also been tilted  even after I align it it seems to revert back to tilt.

jamesedler@hotm Posted at 2016-7-2 08:12
I have had my Phantom 3 professional for about a year now. I have had 10's of flights taking off fro ...

You had a perfect compass calibration but unnecessarily recalibrated it every flight.
Each time risking giving your Phantom a bad compass calibration.
You can safely fly for months with a good compass calibration.
Calibrating every time is completely unnecessary.

guns&cameras Posted at 2016-7-2 08:29
My son just lost his companies Phantom3 this week due to compass error. He said it was up maybe 50'  ...

Not enough details to be certain, but the most common cause of incidents like that is recalibrating the compass close to steel (including reinforced concrete) and then flying away.
The compass has beeen calibrated to compensate for the extra magnetic field but when the Phantom flies away from the magnetic influence >>> compass error.

jamesedler@hotm Posted at 2016-7-2 06:12
I have had my Phantom 3 professional for about a year now. I have had 10's of flights taking off fro ...

I don't know how big your back yard garden is, but if there is a fence nearby or pipes underground they can affect the calibration process even if it has worked before. I honestly don't know if it really is that sensitive, but for safety's sake it should be an open field with no ferrous metals or electro-magnetic interference such as phones and watches.

Do you check your sensor readings before taking off? Check your compass and IMU readings and get an idea what it usually reads when you have a normal flight. If you check it every time, you might be alerted to an abnormal reading.

labroides@yahoo Posted at 2016-7-2 06:54
You had a perfect compass calibration but unnecessarily recalibrated it every flight.
Each time ri ...

I agree. Constant recalibration increases the chance for error. Checking the sensor readings before flying seems like the smartest thing to do. If it does not change significantly then the amount of time or location really doesn't matter.

I thought coming from Ocean City, MD back to Atlanta would have caused some difference due to at least a 2 degree or more change in declination but the sensor reading difference was insignificant. I will recalibrate, but only when I am at a park or football field.

Ok so here's where I'm at. I was sold the Dji phantom 3 professional on the basis that anyone could fly it. With the complete confidence that what was previously only obtainable by professionals was now at my finger tips.
And if anything was to go wrong then I always had the fool proof solution of "return to home". The new phantom 3 was almost idiot proof.
Here's the thing I was that idiot, the one the drone was made for, the one that was supposed to make me be able to film like a professional. So why after parting with my hard earned cash am I at fault because I did all my pre flight checks as recommended and because I didn't know the inside of a knatts but am I to blame for a compass error that took place after a mile into flight.
If it's the case that only nerds should own such a piece of equipment then don't make your advertising as such that someone like me should own it.

jamesedler@hotm Posted at 2016-7-4 06:43
Ok so here's where I'm at. I was sold the Dji phantom 3 professional on the basis that anyone could  ...

I am just itching to reply to that, but in the interests of harmonious relations, I will let that one go through to the catcher. But I will say that it is quite true that 'anyone can fly it', just a matter of how well.

jamesedler@hotm Posted at 2016-7-4 06:43
Ok so here's where I'm at. I was sold the Dji phantom 3 professional on the basis that anyone could  ...

"So why after parting with my hard earned cash am I at fault because I did all my pre flight checks as recommended and because I didn't know the inside of a knatts but am I to blame for a compass error that took place after a mile into flight. "

A bit of understanding goes a long way to helping you fly better and there is a lot to understand.
Getting a handle on what your compass does and what a compass error is important.
A compass error usually doesn't indicate a problem with the compass.
The compass is very reliable and a compass error is usually the compass telling you that it has detected a difference in the magnetic field from what is normal.
But if you mess with  the compass by calibrating in a bad area where the earth's normal magnetic field is distorted by a lot of steel or electric currents in cables etc, you set it to compensate for those distortions.
WHen you fly away from that distortion, the compass d" I have had 10's of flights taking off from my back garden. I regularly reset the Imu and almost always calibrate the compass. "etects the difference from what you had calibrated it for and tells you that you have a Compass Error.

Here is a perfect example:

" I have had 10's of flights taking off from my back garden. I regularly reset the Imu and almost always calibrate the compass. "
Even the badly written manual doesn't suggest that you should recalibrate the compass and IMU every flight.
If your Phantom is flying properly, leave it  alone and don't unnecessarily mess with  it.
Unless you crash or have consistent altitude misreporting, you probably never need to recalibrate the IMU and you can fly safely for a very long time without recalibrating the compass.

Here's a thread that may help you understand what compass calibration is and when it's necessary:  http://www.phantompilots.com/thr ... plete-primer.32829/

I have a  campus problem all so.   I have the phantom 3 advanced model.    Every time I turn on my raido it wants me to recalibrate the compus. What do I need to do to fix this ?

mike.moritz Posted at 2016-7-4 10:50
I have a  campus problem all so.   I have the phantom 3 advanced model.    Every time I turn on my r ...

The Go App is telling you that the compass calibration you have is bad, so you need to perform the compass calibration.

Geebax Posted at 2016-7-4 08:54
The Go App is telling you that the compass calibration you have is bad, so you need to perform the ...

I do calibrate the compus.  When I fly and land and put  a new battery in it wants to calibrate again.

mike.moritz Posted at 2016-7-4 11:02
I do calibrate the compus.  When I fly and land and put  a new battery in it wants to calibrate ag ...

Then it suggests the compass calibration you are doing is not valid. Can you post a photo of the message and also of the compass values, that might be a clue. It might also be a clue that where you are taking off from is a bad location, do you take-off from the ground, or a table?

mike.moritz Posted at 2016-7-4 11:02
I do calibrate the compus.  When I fly and land and put  a new battery in it wants to calibrate ag ...

The obvious thing to look at is where are you calibrating and/or taking off from.
Are you on reinforced concrete?
Do you have the problem if you are out in the open well away from anything steel?

labroides@yahoo Posted at 2016-7-4 10:35
The obvious thing to look at is where are you calibrating and/or taking off from.
Are you on reinf ...

It might be the  concrete.  There are  concrete pads  where I fly

skipilot1 Posted at 2016-7-1 21:09
I agree. Constant recalibration increases the chance for error. Checking the sensor readings befor ...

"Checking the sensor readings before flying seems like the smartest thing to do"

What should I be looking for in a IMU reading? What is normal.
And the compass normal is 1000 to 2000 ? per Ken Or 1450 to 1600 ?Mine is 1470 to 1490 ish if that's the number to the far right (mod).