Mavic Mini "Flyaway" - forensic help requested

[Meta4]

I guess I'm just thinking that having more satellites to choose from (3 different types rather than just 2) might help get more coverage.

It won't
Your problem isn't that there aren't enough sats in your sky.
It's that you can't see enough of the sky.

It's really simple.
If you have a large area of the sky obstructed, you won't get proper GPS reception.

 

[rwilliam99]

I have a Mavic Mini. I was debating getting a Mini 2 and was almost ready to pull the trigger when the Mini 3 Pro came out. Really glad I tend to dither a lot!

Haven't flown my Mavic Mini since I got the Mini 3 — really only keeping it as a backup. Things I like:

• much better wind resistance and stability
• automatic panorama shooting
• the RC controller, which is much better than the original controller and my iPad Mini
• possibly linked to above, much more responsive than the Mavic Mini
• much better range and tolerance for obstacles like trees
• gets GPS lock a lot faster
• better battery life

Almost all of those are reasons why I want to get a mini 3 pro. Battery life isn't really a concern of mine - I typically don't fly TOO far and flights are usually < 10 mins.

What does the automated panorama shooting do? That sounds interesting - I do a lot of that - hike up to some place and then send the drone up for a different perspective.

 

[Yorkshire_Pud]

much more responsive than the Mavic Mini

That's an interesting point, is it?
I think I have seen various comments about that but can't help but wonder is it do to the way people have their settings set, e,g, EXP settings.
Many folks seem to recommend curved EXP profiles but that leads to differing responses at different places on the curve. Depending how far from 0.5 the setting is, that can mean virtually no response near the centred stick position and outer limits with a virtual switch like 'all or nothing' response somewhere between centred stick and full stick.
I set my EXP to 0.5. and the response is, to my mind, predictable and appropriate.
From memory there are other settings that might appear to affect the responsiveness.

 

[BudWalker]

My apologies - I was looking at the fc_log.csv file that DatCon created from the fc_log.log file. My actual fc_log.log file is 512MB. The CSV file is 32GB. The CSV file has almost 8 million rows in it!

If you want to try and extract that flight from it, here is a copy of the fc_log.log file:

https://trailadvocate.org/fc_log.log

The flight occurred on 3/18/2023 at 9:38am (ish). I will leave it up for a week or so and then remove it. That web host doesn't have a ton of free space available.

I looked at the fc_log.log file. It appears that it was recorded while the Mini was powered on for at least 5000 seconds without being connected to an RC, no motor starts, no connection to any GPS satellites, etc. The data from the incident got overwritten. Since there was no GPS data it can't be determined when the Mini was powered up.

 

[rwilliam99]

I looked at the fc_log.log file. It appears that it was recorded while the Mini was powered on for at least 5000 seconds without being connected to an RC, no motor starts, no connection to any GPS satellites, etc. The data from the incident got overwritten. Since there was no GPS data it can't be determined when the Mini was powered up.

Thanks so much for looking - I swear I copied that off right afterwards, but I must have been playing around with it before I copied it. I sincerely appreciate the effort.

I feel pretty confident I understand what caused this crash and will use that knowledge to help me prevent making the same mistake again. I'm absolutely amazed at how much data these things log!

 

[Robert Prior]

What does the automated panorama shooting do? That sounds interesting - I do a lot of that - hike up to some place and then send the drone up for a different perspective.

I shoot a lot of spherical panoramas. Started with my DSLR manually aiming the camera. Did the same thing with my Phantom. Have to be careful to have enough overlap, and so it takes a while.

The automated panorama takes a bunch of overlapping pictures and stitches them into a panorama in the drone with a single press of the shutter. I ignore the panorama and stitch it myself later for better results (to do this you have to change the settings to save the individual pictures). It handles moving the drone and gimbal for you, so that once you press the shutter you just wait for the drone to finish. Not only less work, but also faster than doing it manually.

I almost always shoot three exposure-bracketed spherical panoramas, stitch them using PTGUI Pro, tone-map with Photomatix, and then sometimes crop to a non-spherical image. I find this 'framing in post-production' approach works best for me, so I don't worry too much about lining up the shot just right while also doing all the pilot stuff like monitoring airspace etc.

Equirectangular

All my equirectangular panoramas, which can be displayed as interactive VR images.

www.flickr.com

Upstream from Landmannalaugar, Fjallabak Nature Reserve, Iceland (I) 360 Panorama | 360Cities

360° panorama photo from by Robert Prior. Looking upstream along the stream that leads to Stórhöfði. You can see the brilliant colours o...

www.360cities.net

Stutur Volcano, Fjallabak Nature Reserve, Iceland 360 Panorama | 360Cities

360° panorama photo from by Robert Prior. Hovering above Stutur (spout), an old volcanic cone inside an older volcanic cone near Landman...

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Aerial view of the Sechelt Deep Sea Terminal and Shiploader (IV) 360 Panorama | 360Cities

360° panorama photo from by Robert Prior. Seabulk designed and built this deep sea terminal and shiploader for the export of constructio...

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Aerial View of the Ilulissat Icefjord, UNESCO World Heritage Site, Greenland (III) 360 Panorama | 360Cities

360° panorama photo from Greenland by Robert Prior. Located on the west coast of Greenland, 250 km north of the Arctic Circle, Greenland’s Iluliss...

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Gibsons Harbour on the Sunshine Coast, British Columbia (VI) 360 Panorama | 360Cities

360° panorama photo from by Robert Prior. Gibsons is a coastal community in southwestern British Columbia, Canada on the Strait of Georg...

www.360cities.net

 

[Robert Prior]

That's an interesting point, is it?
I think I have seen various comments about that but can't help but wonder is it do to the way people have their settings set, e,g, EXP settings.
Many folks seem to recommend curved EXP profiles but that leads to differing responses at different places on the curve. Depending how far from 0.5 the setting is, that can mean virtually no response near the centred stick position and outer limits with a virtual switch like 'all or nothing' response somewhere between centred stick and full stick.
I set my EXP to 0.5. and the response is, to my mind, predictable and appropriate.
From memory there are other settings that might appear to affect the responsiveness.

I left the settings at default for both my Mavic Mini and my Mini 3 Pro. What I noticed with the MM was that there was a lag between in either the video feed or responsiveness, so when turning the drone it was really easy to overshoot. (As in letting go of the stick and having the view continue turning for an appreciable period of time.)

Might have been the tablet I was using — it was in spec when I bought the MM but no longer in spec when I noticed the problem, so my hypothesis is that DJI Fly was updated to require a newer tablet and I didn't notice that when updating. In any case, a new tablet cost a significant fraction of a newer more modern drone, so one more reason for the upgrade!

 

[Yorkshire_Pud]

I've not seen a change in GPS icon color. But, I've been mostly flying my FPV and Avata using the goggles. Usually don't use the Fly app, just the goggles.

Just flown a flight starting indoors and flying out side. In the App the indicator started at red and the count 0, the count then jumped to 4 whilst the indicator remained red. The count next jumped to 8 and the indicator turned orange. The indicator then went white thought the count was still 8. The count then went to 10 and climbed to 15, all with a white indicator.
I'll need to fly another similar flight to relate a similar screen capture to the log, the current screen capture doesn't match up to the log very well.

 

[rwilliam99]

Just flown a flight starting indoors and flying out side. In the App the indicator started at red and the count 0, the count then jumped to 4 whilst the indicator remained red. The count next jumped to 8 and the indicator turned orange. The indicator then went white thought the count was still 8. The count then went to 10 and climbed to 15, all with a with indicator.
I'll need to fly another similar flight to relate a similar screen capture to the log, the current screen capture doesn't match up to the log very well.

Given what I saw here, my guess is that the icon turned white when the gpsLevel got to 4. It will be interesting to see if you can confirm that.

 

[Yorkshire_Pud]

Given what I saw here, my guess is that the icon turned white when the gpsLevel got to 4. It will be interesting to see if you can confirm that.

Off the top of my head and from memory I have NEVER seen white below 7.
I quite often take off with the ground in GPS shadow and must wait at 5m for the drone to get sufficient GPS.
However I do not tend to watch the screen, I would normally watch the drone and go by the series of rapid LED flashes that they give when they establish, or reset, the home point.
Then I fly out a short distance, say 50m+ and RTH and let it bring the drone back to what it thinks is the homepoint but I leave it 'up there'. This is just to check where the drone thinks the home point is. If it's not to my liking I reposition the drone and reset the home point to the satisfactory position whilst it has good GPS.

 

[rwilliam99]

Off the top of my head and from memory I have NEVER seen white below 7.

That would match what I was thinking - you said it started out at orange with 8 satellites and then changed to white with still 8 satellites. I'm thinking the trigger to change to white was the gpsLevel going from 3 to 4 - even though the satellite count didn't increase the quality of the connections did which is what I think triggered it to go to white. Maybe there is a lower threshold for # of satellites as well.

I quite often take off with the ground in GPS shadow and must wait at 5m for the drone to get sufficient GPS.
However I do not tend to watch the screen, I would normally watch the drone and go by the series of rapid LED flashes that they give when they establish, or reset, the home point.
Then I fly out a short distance, say 50m+ and RTH and let it bring the drone back to what it thinks is the homepoint but I leave it 'up there'. This is just to check where the drone thinks the home point is. If it's not to my liking I reposition the drone and reset the home point to the satisfactory position whilst it has good GPS.

This is what I think I will start doing, especially in areas that might be tougher for a signal.

 

[Meta4]

That would match what I was thinking - you said it started out at orange with 8 satellites and then changed to white with still 8 satellites. I'm thinking the trigger to change to white was the gpsLevel going from 3 to 4 - even though the satellite count didn't increase the quality of the connections did which is what I think triggered it to go to white. Maybe there is a lower threshold for # of satellites as well.

For someone who professes to understand how GPS works, you continue to miss the basics.
The number of sats is not what matters.
If you can only receive sats from a very small part of the sky, you cannot get a wide spread of sats that is necessary to have reliable GPS location data.
The flight controller determines whether the GPS reliability goes from 2-3-4-5 based on the errors in location data.
To get reliable location data you must have a range of sats at different and large enough angles that you only get with sats spread over a large chunk of the sky.

 

[rwilliam99]

For someone who professes to understand how GPS works, you continue to miss the basics.
The number of sats is not what matters.
If you can only receive sats from a very small part of the sky, you cannot get a wide spread of sats that is necessary to have reliable GPS location data.
The flight controller determines whether the GPS reliability goes from 2-3-4-5 based on the errors in location data.
To get reliable location data you must have a range of sats at different and large enough angles that you only get with sats spread over a large chunk of the sky.

I understand all that - I guess I just don't communicate well.

I will refrain from posting further on this topic....

 

[BudWalker]

The label gpsLevel is a bit misleading. It's not just GPS reliability, or in same way related to a Dilution of Precision value. There can be 20 or 30 satellites spread out so that DOP is < 1 (lower is better) but gpsLevel will be 0.

The location solution is a result of fusing several different data. GpsLevel is the confidence the FC has in that solution. Certainly gpsLevel depends on DOP but it also depends on magnetometer and IMU data. And, there is always the possibility the FC will decide that the location solution is suspect and reduce gpsLevel.

BTW, when gpsLevel gets to 2 the Home Point is recorded. When gpsLevel gets to 4 the HP is set again.

 

[Meta4]

BTW, when gpsLevel gets to 2 the Home Point is recorded. When gpsLevel gets to 4 the HP is set again.

In the OP's incident, OSD.gpsLevel reached 3 at 3:54.9.
But no homepoint was recorded until more than a minute later when OSD.gpsLevel reached 4 at 5:05.7.

At OSD.gpsLevel 3 the flag OSD.isGPSUsed changes to True, but what it's used for doesn't include recording a home point.

 

[rwilliam99]

If you must upgrade then since you are a newbie I'd suggest a second hand Mini 2 rather than a Mini 3. It's cheaper and has the added advantage that you can use the batteries from the Mavic Mini in it. You could always sell the Mini 2 later on.

This comment intrigued me - but I've seen conflicting info. What I found was that the MM batteries can only be used in a mini 2 in the international version. Is there more current guidance on this that you are aware of? Since I'm in the US it does not sound like I could re-used my MM batteries.

 

[Yorkshire_Pud]

I use Mavic Mini batteries in my Mini 2 more than I use Mini 2 batteries in my Mini 2 and my Mini 2 is a "bog standard" Mini 2 sold in the UK. I have even charged Mavic Mini batteries in the Mini 2 charging hub.
I do not know of an "international version" of the Mini 2, as far as I am aware there is only one version of the Mini 2.

There are smaller capacity/weight batteries for Japan ( legal constraint? ) for the Mavic Mini but I think they are the same voltage etc. and interchangeable with 'full sized' Mavic Mini batteries.
The Mavic Mini was sold in two versions, FCC vs CE, but the batteries are interchangable.

 

[rwilliam99]

I use Mavic Mini batteries in my Mini 2 more than I use Mini 2 batteries in my Mini 2 and my Mini 2 is a "bog standard" Mini 2 sold in the UK. I have even charged Mavic Mini batteries in the Mini 2 charging hub.
I do not know of an "international version" of the Mini 2, as far as I am aware there is only one version of the Mini 2.

There are smaller capacity/weight batteries for Japan ( legal constraint? ) for the Mavic Mini but I think they are the same voltage etc. and interchangeable with 'full sized' Mavic Mini batteries.
The Mavic Mini was sold in two versions, FCC vs CE, but the batteries are interchangable.

I found this posting on the dji forum:

DJI Mini 2 - Does it allow the Mavic Mini 1 batteries?

Mavic Mini 2 - Does it allow the Mavic Mini 1 batteries? Are they the same?

forum.dji.com

Which seemed to indicate you could NOT use them, but then I found this posting here:

Battery mini 1 to mini 2?

Hi, baterry from mini 1 is compatibile with mini 2? And bag from MA2 is this same as mini 2

mavicpilots.com

That indicates you CAN use them - and people both from the UK and the US said they successfully used them. Looking further in that thread there is a YouTube video showing someone testing them - although the batteries are different, he got essentially the same flight time out of both.

I'm having a difficult time deciding on which version to purchase - given I can re-use my batteries, I'm now starting to think your suggestion of a used mini 2 might be the best, most prudent way to go. A mini 2 would be a slight upgrade over what I have (4K video), while being significantly cheaper - I could buy 2 mini 2's for what the mini 3 pro would cost. I would really like some of the features of the mini 3 pro, but given my history, wisdom is leading me to go for the mini 2.

 

[Yorkshire_Pud]

The Mini 2 is, without doubt, the better drone but the Mavic Mini is still a competent drone if you fly with its limitations in mind, i.e. it's not the drone for windy conditions. The Mini 2 is somewhat better in that respect, has a better? camera, 4K, and possibly the better range.
That said I haven't pushed my Mini2 to find is absolute range limit but my CE spec Mavic Mini has reached 2km and I have seen one, flown by somebody I was watching reach 2.4km, both were over open sea. I don't normally fly out of VLOS but over open sea I can see anything to which the drone would be a threat and I would ditch the drone in the drink if needs be.
If money is tight then go for the Mavic Mini, the controller and props will, of course, be compatible and the good bits of your wrecked drone will be spares.
If you go for the Mini 2 BE AWARE the props and controller of the Mavic Mini are not compatible with the Mini and you would damage the MIni 2 motors if you try to use Mavic Mini props on the Mini 2, the screws differ in design and so do the screw threads.

 

[rwilliam99]

The Mini 2 is, without doubt, the better drone but the Mavic Mini is still a competent drone if you fly with its limitations in mind, i.e. it's not the drone for windy conditions. The Mini 2 is somewhat better in that respect, has a better? camera, 4K, and possibly the better range.
That said I haven't pushed my Mini2 to find is absolute range limit but my CE spec Mavic Mini has reached 2km and I have seen one, flown by somebody I was watching reach 2.4km, both were over open sea. I don't normally fly out of VLOS but over open sea I can see anything to which the drone would be a threat and I would ditch the drone in the drink if needs be.
If money is tight then go for the Mavic Mini, the controller and props will, of course, be compatible and the good bits of your wrecked drone will be spares.
If you go for the Mini 2 BE AWARE the props and controller of the Mavic Mini are not compatible with the Mini and you would damage the MIni 2 motors if you try to use Mavic Mini props on the Mini 2, the screws differ in design and so do the screw threads.

Well, I finally made up my mind..... I am probably being stupid with this decision, but I opted for the "cadillac" option - I bought a mini 3 pro with the new RC controller. I may end up regretting this decision, but I'm going to give it a whirl.

I really wanted the RC controller (I've had issues with my phone on occasion) as well as the 4k HDR video and obstacle avoidance. Between all that, and more knowledge under my belt, I'm hopeful I can keep from crashing or losing my drone again.

The safe option would have been to go with the mini2 or mini2 SE - but you only live once, right?