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Telemetry data error?

Joined
Jul 19, 2018
Messages
12
Likes
8
Age
63
#1
Hello everyone,
I will try to make this brief and just factual. New pilot, made two flights in the last two days. Beginner mode both times. Updated to latest software versions, using Samsung s8. Calibrated compass, calibrated IMU (Possibly could have done this wrong..did not restart drone after calibrating). Used a landing pad to take off from hovered at 33 ft. to get GPS lock. Whenever I would land I would use RTH...I expected drone to be a little off when landing but today when drone landed it was several feet off (no wind, dead still). With drone landed, props stopped, telemetry showed a "D" of 5 feet. Yesterday "H" on flight report showed a max altitude of 337 feet..again in beginner mode, in addition I was VERY careful yesterday and today...nothing higher than tree top level...if that. Any idea folks why telemetry is off? Searched forum before this post trying to find answers...seems some have suffered severe problems with update causing location issues...could this be related? What do y'all think?
Thanks to all in advance for any help!
Fly Safe
see ya
dave
 

Dragonfly

Well-Known Member
Joined
Nov 12, 2016
Messages
494
Likes
428
Age
58
#2
Hello everyone,
I will try to make this brief and just factual. New pilot, made two flights in the last two days. Beginner mode both times. Updated to latest software versions, using Samsung s8. Calibrated compass, calibrated IMU (Possibly could have done this wrong..did not restart drone after calibrating). Used a landing pad to take off from hovered at 33 ft. to get GPS lock. Whenever I would land I would use RTH...I expected drone to be a little off when landing but today when drone landed it was several feet off (no wind, dead still). With drone landed, props stopped, telemetry showed a "D" of 5 feet. Yesterday "H" on flight report showed a max altitude of 337 feet..again in beginner mode, in addition I was VERY careful yesterday and today...nothing higher than tree top level...if that. Any idea folks why telemetry is off? Searched forum before this post trying to find answers...seems some have suffered severe problems with update causing location issues...could this be related? What do y'all think?
Thanks to all in advance for any help!
Fly Safe
see ya
dave
First mistake, you said you took off and hoverved at 33 feet to aquire GPS.
Always sit on pad and wait for full GPS lock before taking off. This then records an accurate home point and sets all data. You should always wait to hear. (home point has been updated, please check it on the map) before takeoff. You are risking uncontrollable flight and risk of flyaway with what you are doing.
 
Joined
Jul 19, 2018
Messages
12
Likes
8
Age
63
#3
First mistake, you said you took off and hoverved at 33 feet to aquire GPS.
Always sit on pad and wait for full GPS lock before taking off. This then records an accurate home point and sets all data. You should always wait to hear. (home point has been updated, please check it on the map) before takeoff. You are risking uncontrollable flight and risk of flyaway with what you are doing.
Wow...thank you for that! I did hear that on my first or second take off...but then I changed what I was doing for some stupid reason...Thanks Dragonfly, lesson learned..!! Would me taking off like that and hovering account for why D and H were so far off???
 

Dragonfly

Well-Known Member
Joined
Nov 12, 2016
Messages
494
Likes
428
Age
58
#4
Wow...thank you for that! I did hear that on my first or second take off...but then I changed what I was doing for some stupid reason...Thanks Dragonfly, lesson learned..!! Would me taking off like that and hovering account for why D and H were so far off???
Yes
 

Thunderdrones

Well-Known Member
Approved Vendor
Joined
Dec 20, 2016
Messages
7,857
Likes
5,212
Location
Duluth, Georgia
#5
D = Distance and is set by the navigation system including the GPS.

H = Height (altitude) is set by the digital barometric pressure altimeter of the IMU and augments the GPS's trilateration and downward sonic sensors.

It's never a good idea to take off too quickly. As in full scale aircraft, the systems on the Mavic take a minute or two or longer to calibrate and acclimate themselves to the ambient environment. Your main systems include the GPS, compass, IMU, and gimbal. After they are done calibrating it's safe to take off. However, if anything looks wrong, I usually land, power everything off and restart.

This is the Mavics digital barometric altimeter.

IMU.jpg