This may well be obvious to many of you, but it could have involved the loss of my Mini 2 yesterday. I was flying out over the sea, not too far away, when I had a ‘Disconnect’ message aper on Litchi. Up to the point I’d had full strength signals showing and I have no clue as to why it disconnected. I think it was just the video and flight data return link as the drone was still controllable and din’t enter auto RTH. I thought that it might re-connect on its own, but after a short time decided to try a re-start on Litchi, which worked fine and I continued the flight. I had a further disconnect later on and resolved it the same way and eventually came back and landed. It was only when I reviewed the flight data usinh Airdata UAV that I was horrified to find the the Home Point had re-set when I re-started Litchi - right out over the sea! So if I had triggered an RTH or it had auto-triggered, my Mini 2 would have happily flownback out over the sea and landed there. I’m presuming that it showed exactly that on the map but I didn’t notice it. There was unfortunatel no data captured after the second restart.
A disconnect and restarting Litchi shouldn’t change the Home Point. The Home Point is set by the onboard firmware when the drone reboots.
It seems strange that …
- it didn’t initialise RTH, and
- a second log was created - starting at zero flight time.
This does, however remind me of something that happened to me.
Albeit on the older MP, I’ve happily switched between Litchi and the DJI app whilst in flight without the home point changing.
The only 2 times my home point has changed was whilst using the DJI app and when (for whatever, and still unknown, reason) my MP rebooted in mid flight (mid 360 pano, in fact).
The lack of data after the reconnect is also what I experienced.
There are, of course, differences in the way the DI-Fly app drones communicate with their RC … and differences in the way Litchi works with them, too. So, I’m not saying this is “the same issue” … but I do see similarities.
The 360 pano is a form of “autonomous” mode … not totally unlike Litchi.
That was almost 3 years ago, now, and no issues since - with panos, or Litchi, or anything else.
I reported it to Litchi who weren’t (so far, anyway) very helpful. I’m not even sure how to do the first suggestion. I actaully tried to ‘drag the home point icon’ in a cround test this afternoon, but all I did was to move the map, not the homepoint. I checked that I didn’t have ‘Dynamic Homepoint’ enabled (I didn’t), but even if I had, I didn’t move from the launch spot anyway, particularly not over the cliff and into the sea! Maybe I’m missing something (I’ve only just started using Airdata UAV) but it certainly looks to me that the homepoint moved. Anyway, the main point for me is ‘why did I get two disconnects’ which unfortunately the flight data gives no clue to. btw, I managed to find the data for the third flight segment after the second diconnect. I’ve copied the messahe from Litchi below:
Hi,
Here are the only cases where Litchi will change the home point:
if you use the custom functions 'Homepoint at aircraft/device': https://flylitchi.com/help#settings-p3
if you drag the home point icon on the map to a new location
if you have 'Dynamic Homepoint' setting enabled in which case the home point updates to the mobile device location periodically
In your scenario, unless you did any of the above, it sounds unlikely that it came from Litchi. The drone itself also should not normally reset its home point mid flight. Your flight log seems to have the same home point always by the way.
Kind Regards,
Litchi
As I intimated above, and so do they, I don’t think this is an app issue.
Not that that really helps you, of course.
Personally, I’d see what DJI say. (Something I wasn’t really able to do with modified firmware on the MP.)
Can you share the whole flight log(s) instead of just the screenshots from Airdata?
I’m very new to examining flight logs, how do I do this please?
Hi Chris
I found out how to look at the raw flight log (simple when you know how!) and the home point hasn’t actually changed between the three flight segments, so I would have been fine with an RTH, not that I use that except if I really need to, or for practice. It must just be a thing with the graphics on AirData UAV, that it shows the homepoint where the drone was when the app was started, which in most cases will be correct. I’m now wondering if the disconnects were something simple like an intermittant cable connection due to dirt in the USB C connection on the phone, I’ve had that with a tablet before when it wouldn’t charge, just needed a bit of a clean!
I think the mystery is now solved and the home point didn’t in fact change, it was just how it was displayed on the AirData UAV map. For anyone that’s interested still though, here are the links to the raw fligh logs. Thanks Milkmanchris for showing me how to share!
I’d go with that, keep an eye on it or invest a couple of quid in a half decent cable ;o)
Isn’t this the whole point of turning on “dynamic home point”
With this turned on, your home point is always where your remote is. So even if the drone rebooted mid flight, the home point would immediately set to where your remote is?
I know this is not an answer to thr question you are asking, but I do see it as an immediate rectification to the problem ever happening again.
I know it’s not a true fix, but I would say it’s what to do until the problem of found/replicated/fixed
I think now that the problem was probably purely mechanical, possibly due to the silicon case my Galaxy usually lives in obstructing the USB port on this occasion. From talking with Litchi and analysing the ‘raw’ Flight Logs it appears that the Home Point wasn’t in fact updated in the drone, it was just the way the track maps display it. I think that if the drone re-booted for any reason while in flight, it would fall from the sky! The dynamic homepoint option sounds a good one though. I rarely move from the launch location but so far I can’t see any downside to it.