Flyaway and argument over setting home point at "launch"

[old man mavic]

my very first drone came from a well known discount store in the UK it had nothing to help it fly ,was only suitable for indoor use had a 5 min battery life ,after several hours of trial and error i was able to keep it at a steady height and fly around my living room for the whole battery without crashing or landing i learnt a lot about stick input and what the drone did in response to those inputs.
i was bitten and had to move up the drone ladder to better and more expensive drones but i could just have easily gone in the other direction and have thought this is too much trouble to master and given up completely..
my point is this there are many many more very affordable drones on the market now, that have altitude hold and gps with a half decent camera on that can be flown to learn the basics, with the gps turned off if required ie atti mode, and newbies by using them are not going to be worried about losing an expensive drone, mavics are a big investment to many people including myself and are the bees knees of drones, perhaps that is the downside of them, even with all the tech that they have they still need a lot of practise to fly correctly, they are not superhuman and can crash just like any other drone.

 

[Deleted member 94047]

There is something I don't get here. Doesn't the MA do a homepoint update at take off? Mine does that every time. Homepoint recorded as soon as GPS is acquired and then updated at takeoff.

 

[Meta4]

There is something I don't get here. Doesn't the MA do a homepoint update at take off? Mine does that every time. Homepoint recorded as soon as GPS is acquired and then updated at takeoff.

No .. check next time you fly.
Homepoint is recorded as soon as the drone gets a good GPS position fix.
It only updates if you launch with a good (but not good enough) fix and get better satellite reception after lifting off.

 

[Deleted member 94047]

No .. check next time you fly.
Homepoint is recorded as soon as the drone gets a good GPS position fix.
It only updates if you launch with a good (but not good enough) fix and get better satellite reception after lifting off.

I disagree. This is from one of my logs

5.146 : 1705 [L-HOME]First. lati:11.5984070 longti:37.4179504 alti:1744.63
20.128 : 2456 [L-HOME]Update. lati:11.5984045 longti:37.4179579 alti:1744.63

You can see the MA recording a home point first at 5 seconds after motor start and then updating it at 20s after take off. The two entries are even marked differently as "[L-HOME]First" and "[L-HOME]Update". Note also that the first homepoint record was as good as the update which indicates to me this is not so much about a better GPS fix but procedural.

 

[Meta4]

I disagree. This is from one of my logs

You can see the MA recording a home point first at 5 seconds after motor start and then updating it at 20s after take off. The two entries are even marked differently as "[L-HOME]First" and "[L-HOME]Update". Note also that the first homepoint record was as good as the update which indicates to me this is not so much about a better GPS fix but procedural.

Your drone does not record or update its home point when it takes off.
It really doesn't.
Look at flight records from launches in other locations and you probably won't see that.
It won't update unless it recorded a home point under poor GPS conditions and it gets more reliable GPS shortly afterwards
Post the .txt file and I think I'll be able to show you what was really happening.

 

[Deleted member 94047]

Here you go

Edit: I should have mentioned the entries above are from the DAT event stream log, not from the txt flight log.

 

[Meta4]

Here you go

Your first homepoint was recorded under poor GPS conditions at 0:05.9.
Although there were 10 sats acquired, the GPS health was poor, due to a less than ideal spread of sats.
At 0:20.9 the flight controller was satisfied with the accuracy of the GPS data and it updated the homepoint.
You can see the GPS Level here: http://www.phantomhelp.com/LogViewe...htRecord_2019-09-20_[06-08-04]csv-verbose.zip
It is an indication of how reliable the flight recorder considers the GPS data it is getting.
.

 

[Redleg]

Reading these threads really makes me feel for the folks who lose their aircraft. It’s also like seeing a forensic examination develop right before my eyes. Watching @sar104 and @Meta4 figure this out has been fascinating. It’s reassuring to know there are folks who offer so much of their free time to help and educate others in this community.

 

[Dakarenduro]

It only takes a few minutes to learn the basics of controlling the drone and a Mavic is going to be much easier to fly than a cheap toy drone anyway.
The important things to learn are what can go wrong and how to prevent them from becoming a problem.
Since so much of that is related to the app, a cheap drone really isn't much use as a learning aid.

I respectfully agree to disagree!

Yes, you can take a few minutes and learn the basics. But to get proficient requires time, for any aircraft. I prefer knowing that (generally) when I board my commercial airline the pilot has hours and hours of training on a less sophisticated aircraft and has shown mastery of that before he is given command of the big jet.

The same scenario as driving licenses. You get a learners permit to learn the basics before given a full license.

Again, my opinion. I too am sorry the OP lost his drone and I agree with others, the ability to dissect flight logs by you and other 'pro' members is incredible and valuable at the same time.

 

[BudWalker]

Your first homepoint was recorded under poor GPS conditions at 0:05.9.
Although there were 10 sats acquired, the GPS health was poor, due to a less than ideal spread of sats.
At 0:20.9 the flight controller was satisfied with the accuracy of the GPS data and it updated the homepoint.
You can see the GPS Level here: http://www.phantomhelp.com/LogViewe...htRecord_2019-09-20_[06-08-04]csv-verbose.zip
It is an indication of how reliable the flight recorder considers the GPS data it is getting.
.

navHealth (aka gpsLevel, gpsHealth) is a measure of the FC's confidence in it's position estimate. It's not a measure of GPS reliability. Low navHealth (<4 out of 5) will occur with a high GPS DOP but can also occur for other reasons. E.G. when there is reason to suspect problems with the compass.

In this .txt navHealth (blue trace) got to 4 at around 5 secs but the HP (red and green traces) wasn't updated until 21 secs when launch occurred (black trace showing ultrasonic height).

 

[Meta4]

I respectfully agree to disagree!

Yes, you can take a few minutes and learn the basics. But to get proficient requires time, for any aircraft. I prefer knowing that (generally) when I board my commercial airline the pilot has hours and hours of training on a less sophisticated aircraft and has shown mastery of that before he is given command of the big jet.

I'm not sure what you are disagreeing with.
You've agreed that it only takes a few minutes to learn the basics.
I never suggested that the basics are all that's required.
It takes considerable flying time and experience to become proficient.

 

[BigAl07]

I respectfully agree to disagree!

Yes, you can take a few minutes and learn the basics. But to get proficient requires time, for any aircraft. I prefer knowing that (generally) when I board my commercial airline the pilot has hours and hours of training on a less sophisticated aircraft and has shown mastery of that before he is given command of the big jet.

The same scenario as driving licenses. You get a learners permit to learn the basics before given a full license.

Again, my opinion. I too am sorry the OP lost his drone and I agree with others, the ability to dissect flight logs by you and other 'pro' members is incredible and valuable at the same time.

I think we're talking about 2 different tasks here...

• 1) Learning to FLY a sUAS without support items like GPS & Gyro Stabilization
• 2) Learning to operate the "bells & whistles" of a complex & fairly automated sUAS and understanding What-Ifs and how to handle them safely

Let's look at what Meta posted:

It only takes a few minutes to learn the basics of controlling the drone and a Mavic is going to be much easier to fly than a cheap toy drone anyway.
The important things to learn are what can go wrong and how to prevent them from becoming a problem.
Since so much of that is related to the app, a cheap drone really isn't much use as a learning aid.

In this statement, I assume he's talking about learning the "System" of the aircraft such as Go4 and the onboard fail-safes and how they work. He's not talking about learning the basics of flying a sUAS. The Mavic is a self flyer and with it you don't really "learn to fly" but rather learn to suggest to the flight controller what you'd like to happen and let the software make the needed adjustments to make that happen.

There is a LOT to be said for "Learning to fly" with a simple non-GPS/Gyro sUAS because there are times when things go wrong and you need to understand how to fly in a some-what "Manual" environment but those times are fewer and fewer these days.

At the same time we all need to be intimately familiar with the "S" part of UAS *Unmanned Aircraft System*. We need to know how things work, why things work like they do, and WHAT the backup/fail-safes are and what they do. Otherwise you're just an observer watching automation fly your UAS with no clue what to do to resolve the problem. Honestly, we've made it way TOO EASY to Buy & Fly....

Far more often than not we buy the system, read the Quick Start Guide, Charge the Batteries, and hit the Launch button on our device without having a clue as to all the things that are working "under the hood".

 

[RedBaron122]

Thank you all for all your input. It's amazing to have such a helpful community who don't just tell me I'm an idiot (which in summary it looks like I am!). I didn't realise maximum distance was from home and not from the RC.

Amazing analysis of the logs so thank you for your time.

Guess I sit here and feel sorry for myself and save for another year and buy a replacement unit. Shame about DJI refresh and my house contents insurance not covering it ???‍

Maybe I'll buy a refurb.
Thanks again team.

 

[old man mavic]

hope you do get back into the hobby at some point sorry you had to have such a costly loss

 

[globetrotterdrone]

Hope you get back into the sky soon.
Flying out over the sea with a dynamic landing point as a boat is hence all the gadgets a difficult task.

 

[Frustrated]

How do I know if the home point has been accurately recorded. Thanks from a newbie

 

[old man mavic]

How do I know if the home point has been accurately recorded. Thanks from a newbie

watch the screen and wait till the message across the top turns green and says ready to fly you should also hear a message telling you the home point has been recorded please check it on the map, dont take off till you have enough sats locked