The plotting software is Wavemetrics Igor Pro, but you first need to convert the DAT file using @BudWalker's DatCon software.
Battery Died - Drone Lost - Questions
- Thread starter Youser
- Start date
The plotting software is Wavemetrics Igor Pro, but you first need to convert the DAT file using @BudWalker's DatCon software.
Hello dear sar104,
can you help with my case with such picture where to find drone. I already lost 1 day and didn't fint anything.
Sorry for bothering, but really hands are down. This was 2nd day I flight and wind appeared to be so strong so I couldn't return. Pilot's error....
Flight log is in attachment.
Many thanks in advance!
Autolanding was already initiated when the log ended. Your drone had a constant descend speed of 1,8m/s and was at 27 meters height there & blowing away in approx 4m/s. It didn't fly far ... only 15sec until touch down ... approx 60 meters further away.
Try to search between the pins.
(@sar104 ...correct me if I'm wrong here)
Hi @slup. Thank you very much for reply! I've read today, that even after I initiated autolanding, once connection is lost with dron, it's starting RTH automatically anyway. Sorry if didn't mention, I have (had) Mavic Mini.
So I'm expecting it started to go up again till 45 meters and tried to RTH. But wind was pretty huge, so even with race mode it went far away from me(( Am I wrong? Hope this is the case.
Thanks again in advance)
So I'm expecting it started to go up again till 45 meters and tried to RTH. But wind was pretty huge, so even with race mode it went far away from me(( Am I wrong? Hope this is the case.
Thanks again in advance)
As you had manually initiated the landing it would have landed & shut off the motors ... so I doubt it would have started RTH, a restart should only happen if the engines still were idling, check off that distance in between the pins & let us know how it goes.
Hello @slup , this is what I read for Mavic Mini today:
| I ran a series of experiments to determine what happens. Let's say my Mavic Mini is in danger of being blown away by the wind. If I wait too long the Mini might drift downwind far enough that I lose control signal. Then it will automatically go into Return-to-Home with no other option available. If the wind is too strong it may never return. There are plenty of YouTube videos showing exactly that happening. A better choice would be, before losing the control signal, instead immediately try to land in an attempt to safely ditch in a safe spot. But if you lose signal on the way down, the Mini will again go into RTH mode and climb back up into the strong wind and still be carried away. So instead, choose to have it automatically Land-in-Current-Location, so that even if you do lose the signal you're confident it wiill land no matter what. But it doesn't!!! Whenever the Mini loses control signal, even if commanded to Auto-Land, 11 seconds after losing the signal the Mini will always go into RTH mode and climb back to RTH altitude!! Unless you have control signal all the way down, there is no guarantee that the Mini will actually land in the location you've chosen. You may be surprised when this happens. |
The drift rate was coming down fast with altitude. That's a reasonable bounding estimate.
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If that would be true it's a totally new behavior for DJI drones ... do you have a link to this?
In meantime & suggest that you search off that area marked in the map ...
Hello, I found this here - Auto-Land aborts and reverts to RTH when control signal lost.
I will still search again within area you mentioned. Thank you!
IF ... that behavior really is true, and still exist in today's firmware, it will clearly rise the uncertainty level when it comes to drone recovery after a blow away. And definitely "seal the deal" as soon as you facing a head wind stronger than your Mini & it can't achieve a heading speed towards HP... you will not be able to permanently leave RTH height unless the battery is nearly depleted.
If this scenario actually happened your Mini didn't reach ground in those 11sec disconnect time before RTH supposedly should have been initiated. 7m from ground & 44m from the last position in the log the RTH should have been started, sending up the Mini to 46m height again. After that it continued to drift approx. 1,5km further away. Approximated a square 160x170m shown below as possible for a touch down.
Flight path scenario:
Hello @slup, much appreciate for time you spent for analysis!
Finally I found drone today. And it's still alive. So as expected it canceled auto landing, and initiated RTH. I was pretty lucky that battery was already low so it didn't flew so far, but anyway it did another 800m further. Marked on your graphic where exactly I found it.
Do you have any ideas if I can still retrieve log from this flight directly from copter? As I didn't have full log in application. Would be interesting to see how it looks like.
Many thx again for your time!
Finally I found drone today. And it's still alive. So as expected it canceled auto landing, and initiated RTH. I was pretty lucky that battery was already low so it didn't flew so far, but anyway it did another 800m further. Marked on your graphic where exactly I found it.
Do you have any ideas if I can still retrieve log from this flight directly from copter? As I didn't have full log in application. Would be interesting to see how it looks like.
Many thx again for your time!
Good that you walked that corridor between the red lines ...
I'm still no pro (if ever...) when it comes to these kind of estimations over longer distances, @sar104 is the King here. He got my thinking about this & hopefully he have time to overview it & pinpoint my mistakes ... can say that he predicted that my estimation was somewhat 400m to long 
Then regarding the logs ... no, the AC DAT log is encrypted & can only be read by DJI.
Good that you walked that corridor between the red lines ...
Then regarding the logs ... no, the AC DAT log is encrypted & can only be read by DJI.
Glad it was found, and a good opportunity to assess predictive accuracy. I did suggest to @slup that he was long on the estimate. This is what I did:
:That separates the remaining flight into 4 segments: the remaining initial descent, climb back to RTH height, drift at that height, and autoland descent to the ground, with the estimated times shown above. What's required is to estimate course and speed for those segments. That needs a look at course, height and speed for the end of the recorded flight:
From that we can estimate around 8 m/s at the RTH height, but only around 4 m/s at 25 meters above ground. I used averages for the climb and descent, and 8 m/s for the drift. That gives the following:
Sounds like that was at least in the ballpark for where it ended up.
Great @sar104 ... the more you wave with your Igor Pro & show the easy way of extrapolating the graphs ... the nearer I comes to invest, only thing that stands in between now is the wife already thinking I'm looking to much on exotic curves ... graphs I mean
?
Great @sar104 ... the more you wave with your Igor Pro & show the easy way of extrapolating the graphs ... the nearer I comes to invest, only thing that stands in between now is the wife already thinking I'm looking to much on exotic curves ... graphs I mean
But just think how much money you could make from log analysis...
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