Compass calibration....ongoing question

[Meta4]

Another topic that I forgot to ask when chatting with DJI is the throttle down for 3 seconds in flight not shutting off the motors. I have watched videos and read so many posts showing and stating they will NOT. But the newbie in me....its hard to bring myself to perform this action in flight when on the ground that action kills the motors. Will have to just face my $1000 fear and do it I guess. Lol

This gets asked almost every week.
It is 100% safe to hold the left stick down for descending.
This has been tested by hundreds of flyers hundreds of times.
The clever guys that designed the Phantom wouldn't make the standard descent method also kill your Phantom.

 

[ianwood]

Ask DJI support the same question 10 times and you'll get 10 different answers. I should be shocked that they told you to calibrate every time but I'm not. Not at all.

 

[Meta4]

It's unlikely anyone is going to run into any issues with repeated, unnecessary calibrations therefore.

On the contrary, repeated unnecessary calibration risks getting a bad compass calibration and that can cause you to lose your Phantom.
The kind of people that make repeated unnecessary calibrations, often don't understand what compass calibration is about and don't understand the importance of doing it somewhere away from the influence of iron and steel objects.

I calibrate every time. Even after I change batteries. The reasoning is because I have noticed when I do this every time, when I push the return to home button the Phantom will land within 1-5ft of the original takeoff spot. When I do not calibrate, it will land 5-10ft from the original takeoff spot. This is the only difference I have seen. I want it to always be precise.

That's just coincidence in your observations. More testing of that theory would come up with many flights showing the opposite result as well.
The compass (direction) and GPS (location) are completely unrelated sensors.
What you have observed is due to the random error in GPS precision.
GPS is only accurate to +/- 3 metres most of the time and sometimes even more.
Compass calibration will not improve GPS precision.

I have never heard of a bad compass calibration on a P3. They are either calibrated, or they're not. If they're not, then it would state the calibration was not successful. And because of this, a compass calibration is piece of mind. The task itself is just too easy to do to not insure the process is set to go.

Not at all. It is very possible to get a bad calibration and this forum has many examples of people doing it.
When you calibrate, it is to allow your compass to correctly tune in to the earth's normal magnetic field and ignore the influences of all the bits of metal and electric current running around your Phantom.
If you do this in an area where the earth's normal magnetic field is distorted by iron or steel objects (like on a concrete structure full of steel reinforcing or on a steel ship), you can "successfully" calibrate your Phantom's compass to work in the distorted field of that location but when you fly away from that magnetic influence, your compass is screwed up and unable to work with the earth's normal magnetic field.

 

[todd hawkeye]

When I calibrate the compass my screen tells me to do it horizontally. When I do that it then tells me to do it nose down. When I do that my screen never acknowledges that I did it nose down. How come

 

[msinger]

Are you sure you're doing it right?

 

[BudWalker]

When I calibrate the compass my screen tells me to do it horizontally. When I do that it then tells me to do it nose down. When I do that my screen never acknowledges that I did it nose down. How come

I think that's what I see. I'm supposing that if you didn't it would just keep telling you to do it. I'm thinking that not communicating that it's done is somewhat like what some people's experience DJI repair.

 

[todd hawkeye]

Thanx this is all new to me

 

[ianwood]

Are you sure you're doing it right?

Notice that not only is she indoors but she's wearing a watch.

 

[msinger]

Notice that not only is she indoors but she's wearing a watch.

Right. And, you're completely missing the technique that she's demonstrating.

 

[ianwood]

Right. And, you're completely missing the technique that she's demonstrating.

No. Not missed. Just pointing out how often demonstrations also demonstrate bad habits. If they're going through the trouble of telling you how to do it, they should do it properly.

 

[Meta4]

I had an issue I needed to discuss with DJI and while on the chat I ask this question and received an answer of yes it is recommended by DJI to perform a calibration before every flight. Later in the discussion I brought this up again to clarify and he confirmed it again even if flying in the same area.

Here's a post from a DJI guy that knows a bit more than their phone people ...
DJI Forum|I want to make sure I fully understand the RTH feature.

 

[flyNfrank]

Not at all. It is very possible to get a bad calibration and this forum has many examples of people doing it.
When you calibrate, it is to allow your compass to correctly tune in to the earth's normal magnetic field and ignore the influences of all the bits of metal and electric current running around your Phantom.
If you do this in an area where the earth's normal magnetic field is distorted by iron or steel objects (like on a concrete structure full of steel reinforcing or on a steel ship), you can "successfully" calibrate your Phantom's compass to work in the distorted field of that location but when you fly away from that magnetic influence, your compass is screwed up and unable to work with the earth's normal magnetic field.

So then in this case someone has surely put together a demo of it on youtube for a P3 by now, don't you think? I would not say anything beyond how often I do a calibration except I have had one to one conversations with the China man in charge of writing the firmware. He says it's good to do on each power up before flight.

 

[Mannsp3a]

This gets asked almost every week.
It is 100% safe to hold the left stick down for descending.
This has been tested by hundreds of flyers hundreds of times.
The clever guys that designed the Phantom wouldn't make the standard descent method also kill your Phantom.

Ya I know it has been discussed a lot I have searched it and found many threads on the topic. But figured I would mention it, this also is a common subject of misinformation possibly. When I originally ask on the chat I precisely explained which stick and which movement I was speaking of. I ask about that stick movement alone.
The persons response was "yes if you pull both sticks toward the center the motors will shut off"
So again I had to reiterate what I had already clearly stated but they misread my question. I stated "I'm aware of the csc" and went on to elaborate again. That is when the person stated it would shut off the motors.
I spoke with them over the phone after waiting for 35 callers before me. A lady finally answered and when asked that question she again went that direction and was explaining a csc to me. Hahaha it's like pulling teeth was hoping I might be speaking to a tech that knew where I was going before I said it. The whole thing is a little frustrating.
And on the calibration....damned if you don't and something happens that will be their out. And if you do and get a bad calibration.....Hmm

 

[Robmora33]

On the contrary, repeated unnecessary calibration risks getting a bad compass calibration and that can cause you to lose your Phantom.
The kind of people that make repeated unnecessary calibrations, often don't understand what compass calibration is about and don't understand the importance of doing it somewhere away from the influence of iron and steel objects.

That's just coincidence in your observations. More testing of that theory would come up with many flights showing the opposite result as well.
The compass (direction) and GPS (location) are completely unrelated sensors.
What you have observed is due to the random error in GPS precision.
GPS is only accurate to +/- 3 metres most of the time and sometimes even more.
Compass calibration will not improve GPS precision.

Not at all. It is very possible to get a bad calibration and this forum has many examples of people doing it.
When you calibrate, it is to allow your compass to correctly tune in to the earth's normal magnetic field and ignore the influences of all the bits of metal and electric current running around your Phantom.
If you do this in an area where the earth's normal magnetic field is distorted by iron or steel objects (like on a concrete structure full of steel reinforcing or on a steel ship), you can "successfully" calibrate your Phantom's compass to work in the distorted field of that location but when you fly away from that magnetic influence, your compass is screwed up and unable to work with the earth's normal magnetic field.

Totally understand and some great points here. Thank you. I am just going off what DJI recommends and what has worked good for me. I have now over 30 flights with it, calibrating everyone new battery. Most likely not calibrating exactly in the same location because I am walking usually, but pretty close in proximity. It seems to be doing absolutely perfect. I have never calibrated around metal objects yet, so I will defiantly keep that in mind. Here is one video I did the other day. Thanks again for the information. Cheers!


DJI Phantom 3 Professional-Walk through the Woods 1-7-16.mp4

 

[msinger]

calibrating everyone new battery

What exactly are you hoping to gain by this? Do you fear the previous calibration is lost when powering down your Phantom? Or, is it perhaps some kind of superstition? (I'm just curious.)

 

[Dirty Bird]

I virtually never calibrate the compass unless I am more than 30 miles from my previous location. The app & aircraft alert you if the compass calibration seem suspect & requires recalibration.