Mavic Pro flew away following erratic flying, loss of control

[droneuser]

sar104 - is there any way you could write up a tutorial on how to calculate where a drone may have crash/land? that would be much appreciated

 

[sar104]

sar104 - is there any way you could write up a tutorial on how to calculate where a drone may have crash/land? that would be much appreciated

I'm in the process of writing a guide to log analysis, and I can certainly add something on that subject. It's not particularly complex though - the graph in post #10 is fairly self-explanatory.

Once you have the log file then you can plot battery percentage as a function of time which allows you to extrapolate forwards. I used a linear least square fit to the last 100 seconds of data in this case since the rate was not linear across the entire flight record, but you could just eyeball it. That allows you to estimate the time to autoland - that depends on the critical low battery level, which is also recorded in the log - 10% in this event. You also have distance as a function of time, and you can extrapolate that forwards to the estimated time of critical low battery, giving distance travelled at the autoland point. On Google Earth you can plot that using the direction of travel at connection loss, wind vectors, or a combination of the two, to get an estimated landing point.

You can include additional subtleties with error estimating to get confidence intervals on time, distance, track and wind velocity changes with altitude, but often that's really overkill.

 

[droneuser]

or would be really cool if someone could make a program and a person enter in the data

 

[droneuser]

ok cool thanks sar104

 

[sar104]

or would be really cool if someone could make a program and a person enter in the data

There's probably a bit too much user intervention needed to automate it effectively, at least not without a significant amount of work. I've automated individual elements of the data reduction within the analysis software that I use, but that's about it.

 

[Qoncussion]

This may be somewhat inaccurate with those winds, but you might be able to narrow down your search area. After losing connection it will have stayed in RTH mode and continued to drift until it reached critical battery autoland. Extrapolating power drain rate gives the following distance estimate:

View attachment 32675

That suggests it may have auto landed in the region of 3700 m from the home point. That gives the following estimated location, at the intersection of the line and the circle:

View attachment 32676

Every morning I wake up feeling smart ~until I see stuff like this. And @msinger ~not too shabby, either. I'm going to go throw some poo on the wall now.

 

[droneuser]

yes that that makes sense I guess it would depend on how its done what analysis software do you uses?

 

[droneuser]

msinger - what is your way of calculating where a drone crashs/lands?

 

[sar104]

yes that that makes sense I guess it would depend on how its done what analysis software do you uses?

It's a data analysis package for moderately complex research use - Wavemetrics Igor Pro. Somewhat equivalent to MatLab. It has a lot of built-in standard functions but also supports compiled user programmable procedures, which makes it ideal for dealing with large datasets.

 

[droneuser]

It's a data analysis package for moderately complex research use - Wavemetrics Igor Pro. Somewhat equivalent to MatLab. It has a lot of built-in standard functions but also supports compiled user programmable procedures, which makes it ideal for dealing with large datasets.

I look up MatLab wow that's some software! by the time I learn it there would be a mavic pro 5 out!...lol but does it boil down to wind speed, direction of wind speed, weight of drone, speed of drone, height the drone is at, and with last know GPS reading? to get an general idea of the area to look?

 

[tictag]

Wow! Did not expect this thread to end positively!! Yay to this forum and its members (talking to you @sar104 and you, @msinger ). Glad you got your bird back. Hope she's thawed out now.

 

[droneuser]

yes members on here are great and very helpfully! if it wasn't for people like @sar104 and @msinger we would have gone for ever mavics !!!

@msinger - how do you calculate to find drone?

@sar104 - if you need any help with that tutorial let me know! I may not have the answers BUT I can type things out, etc

 

[sar104]

I look up MatLab wow that's some software! by the time I learn it there would be a mavic pro 5 out!...lol but does it boil down to wind speed, direction of wind speed, weight of drone, speed of drone, height the drone is at, and with last know GPS reading? to get an general idea of the area to look?

It's simpler than that - it's just rate of battery depletion and drift velocity (recorded before disconnect) plus descent time if the altitude is significant.

 

[droneuser]

ahhh ok I cant wait to see the tutorial so I would assume that's how msinger does it too? or is there more then one way to do it?

 

[msinger]

@msinger - how do you calculate to find drone?

Like @sar104, I used data from the flight log and knowledge of how Mavics fly to guesstimate the location.

 

[droneuser]

Like @sar104, I used data from the flight log and knowledge of how Mavics fly to guesstimate the location.

do you uses any other software beside the log viewers?

 

[msinger]

do you uses any other software beside the log viewers?

Yep. I also use Excel, Google Earth, and a calculator.

 

[droneuser]

I would assume you uses excel to help with the math part ?

 

[msinger]

Sure, you could use Excel to do calculations if needed.

 

[droneuser]

have you thought about writing a tutorial?