Flying lower than takeoff altitude.

Joined
Sep 16, 2019
Messages
97
Reaction score
22
Age
71
Location
Florida Panhandle
My question is if flying from a bluff or cliff and actually flying at a lower altitude does the RTH altitude remain constant? If the RTH button is pressed will the drone climb above the TO point and continue to the designated RTH altitude?
 

Meta4

Moderator
Staff Member
Premium Pilot
Joined
Jan 8, 2014
Messages
14,747
Reaction score
8,741
My question is if flying from a bluff or cliff and actually flying at a lower altitude does the RTH altitude remain constant? If the RTH button is pressed will the drone climb above the TO point and continue to the designated RTH altitude?
The RTH height, like all heights is relative to the height of the launch point.
 
  • Like
Reactions: Rick218
Joined
Oct 24, 2020
Messages
80
Reaction score
116
Age
50
Location
Melbourne, Australia
My question is if flying from a bluff or cliff and actually flying at a lower altitude does the RTH altitude remain constant? If the RTH button is pressed will the drone climb above the TO point and continue to the designated RTH altitude?
As per Meta4's answer above, descending below your takeoff elevation won't impact your RTH settings.
On a somewhat tangential but related topic: The programmed elevation ceiling that prevents us from ascending beyond 500 metres, does not apply when descending beyond the same distance. This means that you can fly down the side of a mountain to more than 500 metres below your takeoff point, while not being able to do the same in reverse. I don't recommend testing this, as you would likely be flying beyond VLOS.
 
  • Like
Reactions: MTO
Joined
Dec 8, 2016
Messages
684
Reaction score
231
Location
Nova Scotia , Canada
My question is if flying from a bluff or cliff and actually flying at a lower altitude does the RTH altitude remain constant? If the RTH button is pressed will the drone climb above the TO point and continue to the designated RTH altitude?
Launch point altitude is always recorded as 0 , flying below launch point will show negative numbers , when RTH happens your drone will ascend to 0 altitude THEN ascend to your set RTH height , then come home .
 
  • Like
Reactions: cneedelman and MTO

Capt KO

Capt KO
Joined
Feb 13, 2019
Messages
2,380
Reaction score
2,005
Age
69
Location
IRB, Fl
Be sure to maintain gps while descending into a narrow valley or gorge. Otherwise, in atti, you may not be able to return to your takeoff height. Atti mode restricts your height "above ground" which is under the drone. Not the takeoff ground level.
Have fun.
 
  • Like
Reactions: cneedelman and MTO
Joined
Oct 24, 2020
Messages
80
Reaction score
116
Age
50
Location
Melbourne, Australia
Be sure to maintain gps while descending into a narrow valley or gorge. Otherwise, in atti, you may not be able to return to your takeoff height. Atti mode restricts your height "above ground" which is under the drone. Not the takeoff ground level.
Have fun.
I'm confused about your comment re ATTI mode restricting your height above ground. You don't say what the height-above-ground restriction is. However, once beyond the range of the downward positioning system, how would the drone know its height above ground level?

My understanding is that RTH still works in ATTI mode. The determining factor would be whether or not the drone has a GPS fix. I wonder how the drone would behave if you flew it down into a gorge, it lost GPS signal (switched to ATTI mode), and you then pressed RTH or lost controller connection and needed it to initiate RTH of its own accord? Would it just sit there (or perhaps drift - if no downward positioning) or would it ascend to RTH elevation, collect the satellites on the way up and then safely return? You'd hope it would begin its ascent, irrespective of GPS fix.
 

Meta4

Moderator
Staff Member
Premium Pilot
Joined
Jan 8, 2014
Messages
14,747
Reaction score
8,741
I'm confused about your comment re ATTI mode restricting your height above ground. You don't say what the height-above-ground restriction is. However, once beyond the range of the downward positioning system, how would the drone know its height above ground level?
The problem only occurs if the drone gets to a point where:
1. It has no GPS
2. It detects something below it in range of the downward facing sensors
This is a very uncommon situation .. I've only seen reports of it on three occasions

Rge namual gives details on p54:
Height is restricted to 26 feet (8 meters) when the GPS signal is weak and Vision Positioning is activated.
Height is restricted to 164 feet (50 meters) when the GPS signal is weak and Vision Positioning is inactivated.
I wonder how the drone would behave if you flew it down into a gorge, it lost GPS signal (switched to ATTI mode), and you then pressed RTH or lost controller connection and needed it to initiate RTH of its own accord? Would it just sit there (or perhaps drift - if no downward positioning) or would it ascend to RTH elevation, collect the satellites on the way up and then safely return? You'd hope it would begin its ascent, irrespective of GPS fix.
Try some testing to find out.
I suspect it would do exactly what it would do if above the level of the launch point without GPS ... it would land.
 
  • Like
Reactions: Pygar70
Joined
Feb 21, 2020
Messages
112
Reaction score
59
Age
76
On a point of clarification, allow me a few simple questions to better understand the difference be tween GPS and ATTI modes as far as drone control is concerned.
  1. Is the HP determined and set under GPS? No GPS signal no HP and RTH?
  2. Is ATTI mode totally "SANS" (without) GPS, and if so RTH is only possible in GPS modes.
  3. Down the valley beyond GPS AC will switch to ATTI and have to be flown back manually - no RTH until GPS becomes active again?
It may be basic questions, but it will help me be a better pilot.
 

Meta4

Moderator
Staff Member
Premium Pilot
Joined
Jan 8, 2014
Messages
14,747
Reaction score
8,741
Reply
  1. Is the HP determined and set under GPS? No GPS signal no HP and RTH?
Yes, your drone records a homepoint when it first gets good GPS location data, shortly after powering up, if you launch where the drone gets good GPS reception.
Is ATTI mode totally "SANS" (without) GPS, and if so RTH is only possible in GPS modes.
If the drone is in atti mode because you switched to atti mode, GPS is still working and the drone's position is recorded every 1/10th of a second but GPS is not used for horizontal position holding.
As long as GPS is available RTH will use GPS.
But if the drone is in Atti Mode because you are flying in a non-GPS environment (a cave or canyon etc) of a malfunction causes the drone to lose GPS, then the drone cannot RTH because it won't have GPS.

Down the valley beyond GPS AC will switch to ATTI and have to be flown back manually - no RTH until GPS becomes active again?
Down in what valley?
If the drone has a good view of most of more than half of the sky, it should still have GPS.
If you are asking about a narrow canyon where only a small part of the sky is showing, it probably won't have GPS.
 
  • Like
Reactions: TontoFAC

New Threads

Forum statistics

Threads
140,509
Messages
1,448,388
Members
102,304
Latest member
Ty222