Mavic 2 wants a compass calibration 30 days after last one

[BudWalker]

Bud: Up to this point, I've never needed to look at .DAT files so I'm a rookie with DATcon and CSView but first, it now seems like there are two folders on an iOS device, "FlightRecords" and "FlightLogs." I see only the encrypted .TXT files in FlightRecords and only .DAT files in FlightLogs but these data files are very small as in less than 1k.

However, there's a subfolder under FlightRecords that also contains .DAT files and these are probably what you want since they're much larger than the tiny .DAT files mentioned above.

In \..\FlightRecords\MCDatFlightRecords\ I have five .DAT files with yesterday's date. I don't know why the forum software will not accept the .DAT file extension for uploads but I have archived the first two (chronologically) .DAT files in the attached .ZIP.

Yes, the aircraft requested a calibration upon unpacking but has not asked again until yesterday. That initial cal was on 8/28 so having it pop up on 9/29 (I didn't fly on Day 30 due to rain so it was one day beyond 30 when it asked.)

If neither of these provides the info you need, holler and I'll zip up the other three. I did take a look at the exported .CSV for these two attached files and only see "False" in the different compass error fields.

TIA,

KB

As I mentioned in my previous post the calibration request wasn't due to the 30 day clock. There were no entries in the eventLog stream that looked like
34.367 : 1922 [L-COMPASS][mag_cali_pt] date_from_last 30|

But, there is an interesting wrinkle here. After the calibration the eventLog stream shows this
-50.549 : 18837 [L-COMPASS][scale cali(0)] estimation error:[31.0]
-50.549 : 18837 [L-COMPASS][scale cali(0)] succeed! bias:624.5 530.1 -601.6 scal:3.215 2.994 3.157|
.....
-50.549 : 18837 [L-COMPASS]mag cali pos and time saved success!
-50.548 : 18837 [L-COMPASS][mag_cali_pt]lat:0.482559, lon:-1.698791
-50.548 : 18837 [L-COMPASS][mag_cali_pt]height:-3.7, date:20320214

Whereas my calibration showed this
-35.447 : 4531 [L-COMPASS][mag_cali_pt]height:480.2, date:20180928

and @sar104 's showed this
145.088 : 8407 [L-COMPASS][mag_cali_pt]height:2256.3, date:20180829

Looks to me like you're not going to be afflicted with the 30 day calibration rule. How come you're lucky and I'm not?

 

[kilomikebravo]

You were lucky. If the M2 had sat longer on the ground the effects of the distortion would have had time to affect the Yaw value, possibly causing erratic flight and/or a fly away.

Whoa! First, thanks SO much for the evaluation of the .DAT files, Bud..what would all of us ever DO without you super smart guys?!

Yes, it sure sounds like I was VERY lucky indeed. Extremely interesting that the savior was the time out of the distortion and certainly something I will remember.

When the first compass error showed up in Go4, I moved the M2 about twenty feet away BUT, still on the concrete. The error persisted so I calibrated and the error went away. But what I'm confused about is..if the cal was not successful due to the interference from the rebar, why did the Go4 error go away and, why did the magMod value return to normal? Then again, maybe I can answer my own question, i.e., the aircraft never actually NEEDED a cal, it was merely the interference that threw the error and once I picked it up to DO the cal, everything returned to normal. Do I have even a remote understanding of this event?

Last question, if it only takes a foot or so to get out of the rebar distortion at this particular location, could I launch from say a two-foot wooden or cardboard box sitting on the concrete or would that be "teasing the animals?"

Again, I truly can't thank you enough and yesterday will be the last time I ever launch from a concrete surface!

KB

 

[BudWalker]

Whoa! First, thanks SO much for the evaluation of the .DAT files, Bud..what would all of us ever DO without you super smart guys?!

Yes, it sure sounds like I was VERY lucky indeed. Extremely interesting that the savior was the time out of the distortion and certainly something I will remember.

When the first compass error showed up in Go4, I moved the M2 about twenty feet away BUT, still on the concrete. The error persisted so I calibrated and the error went away. But what I'm confused about is..if the cal was not successful due to the interference from the rebar, why did the Go4 error go away and, why did the magMod value return to normal? Then again, maybe I can answer my own question, i.e., the aircraft never actually NEEDED a cal, it was merely the interference that threw the error and once I picked it up to DO the cal, everything returned to normal. Do I have even a remote understanding of this event?

Last question, if it only takes a foot or so to get out of the rebar distortion at this particular location, could I launch from say a two-foot wooden or cardboard box sitting on the concrete or would that be "teasing the animals?"

Again, I truly can't thank you enough and yesterday will be the last time I ever launch from a concrete surface!

KB

The calibration is just a distraction in all this. It wasn't necessary and was successful. All you really had to do is hand launch or from an elevated platform.

One thing you can do is check that the heading indicator in the map display is consistent with the M2's actual heading. In your case you would've seen that both the heading indicator and the actual orientation were both 103°. I.e., no problem. If you had left the M2 on the concrete the Yaw would have been slowly affected and you would have seen the map heading indicator start to rotate, becoming inconsistent with the actual heading.

MagMod returned to normal because the M2 was being held out of the distortion. Once you placed it on the concrete again the abnormal magMod returned. Finally, when it ascended out of the distortion after launch the magMod returned to normal.

 

[kilomikebravo]

The calibration is just a distraction in all this. It wasn't necessary and was successful. All you really had to do is hand launch or from an elevated platform.

Actually, because I had read so many posts on this subject, I actually did check the heading indicator and I could tell it was very close to East which is how I intentionally oriented it when I set it down. Me thinks I should start learning how to hand launch.

Question: Which of those two applications generated the graph and can I see the same thing myself? (Not that I'd know what I'm LOOKING at, mind you, I'm just curious.)

Thanks a million, Bud...REALLY, you may have saved me fifteen hundred bones now that I know NOT to launch on concrete. Some of us have to be hit in the head about six times with a five-pound sledge before we catch on. <smile>

 

[4wd]

Mine wanted compass calibration today and it's day #31 since first use.

 

[BudWalker]

........
Question: Which of those two applications generated the graph and can I see the same thing myself? (Not that I'd know what I'm LOOKING at, mind you, I'm just curious.)
....

I used CsvView which can be obtained by going to
CsvView Downloads

 

[BudWalker]

Mine wanted compass calibration today and it's day #31 since first use.

But, was it 30+ days since the last compass calibration?

 

[4wd]

But, was it 30+ days since the last compass calibration?

Probably, I can't think of any other reason.
It wasn't used since day #29, and was done on day one

 

[DanMan32]

How do you upload DAT files here? I have another post that presents a situation i'd like analyzed.

 

[msinger]

How do you upload DAT files here?

Upload them to a file sharing site (like Dropbox) and post the download link here.

 

[sar104]

How do you upload DAT files here? I have another post that presents a situation i'd like analyzed.

Mobile device DAT files - just change the file extension to .txt and upload. Aircraft DAT files are too large for that, so upload them to Dropbox or Google Drive (no need to change the extension) and post a link back here.

 

[kilomikebravo]

just change the file extension to .txt and upload

Duh..so the file ext is the issue..thanks, SAR.

 

[DanMan32]

I thought of changing the extension. With M2 there doesn't yet seem to be a way to get the AC flight data. Doesn't work with assistant. At least not with my desktop, didn't try laptop yet.

 

[BudWalker]

I thought of changing the extension. With M2 there doesn't yet seem to be a way to get the AC flight data. Doesn't work with assistant. At least not with my desktop, didn't try laptop yet.

The Mavic 2, and the Mavic Air .DAT files from the AC are encrypted. However, the tablet .DAT files are not encrypted. Look here to see how to retrieve the tablet .DAT.

 

[Meta4]

I thought of changing the extension. With M2 there doesn't yet seem to be a way to get the AC flight data.

It works just fine using the .txt file from the app and the Phantomhelp log viewer

 

[gnirtS]

Ive extracted the tablet .DAT files for when i move a large distance it prompts to calibrate but DatCON says none are valid .DAT files.

Any idea how to read these to see the actual line where it demands calibration?

Edit:- allow invalid data header option fixed it.

 

[sar104]

Ive extracted the tablet .DAT files for when i move a large distance it prompts to calibrate but DatCON says none are valid .DAT files.

Any idea how to read these to see the actual line where it demands calibration?

Are you quite sure that you have the correct DAT files? Which directory did you get them from?

 

[msinger]

@gnirtS, you should be grabbing the DAT files from the "MCDatFlightRecords" directory.

 

[gnirtS]

@gnirtS, you should be grabbing the DAT files from the "MCDatFlightRecords" directory.

I did. DatCon needed to allow invalid headers to work so sorted.

Still doesnt show any calibration being done though, even on 2 flights where i was prompted and calibrated.

Although the one incidence i calibrated and DIDNT fly. Not sure the tablet is logging that.

 

[sar104]

I did. DatCon needed to allow invalid headers to work so sorted.

Still doesnt show any calibration being done though, even on 2 flights where i was prompted and calibrated.

Although the one incidence i calibrated and DIDNT fly. Not sure the tablet is logging that.

It cannot not (excuse the double negative) show the calibration occurring. It must not be the correct file(s).