I own a couple of Mavics a half mile up a mountain behind my house. I would like to be able to drop the drone in a canyon that is below line of sight and still be able to communicate with it. Is there any way to accomplish this?

Two things would make it risky.

One is the possible loss of GPS coverage if the canyon is deep and narrow. I would watch the satellite count while descending and stop if it goes below 75% of normal count in the area.

Second is the loss of signal. If you are on the rim, it could work best. But if you are far away, it may result in signal loss and RTH would be invoked in that case. I have seen instances where the opposite wall of a depression was good enough to reflect signals back to the drone however.

Just give it a try....owning a couple of Mavics.....   

If it looses GPS down in the canyon a altitude limit will be initiatedto your mavic, so you will never be able to fly your drone out (climb) of the canyon.

cheers
JJB

I would like to be able to drop the drone in a canyon that is below line of sight and still be able to communicate with it.

Any possible reflection of signal cannot be relied on.
You need to have a clear, unobstructed line of sight to be able to control your drone.
If you want to fly down, do it from somewhere you can keep a visual on the drone.

Any obstacle will decreace the signal range of the control and transfer signal from the RC to AC and back. If the canyon wide enough then you got luck and the AC receives 7 or 8 satellites and you get the message GPS signal weak. If not you´ll lose that signal and get message <ATTI - Mode>.

GaryDoug Posted at 4-10 17:43
Two things would make it risky.

One is the possible loss of GPS coverage if the canyon is deep and narrow. I would watch the satellite count while descending and stop if it goes below 75% of normal count in the area.

thanks. that was very helpful

Programming your flight with Litchi will definitely allow your drone to descend into a valley below the launch point elevation.  Litchi allows the setting of negative altitudes, specifically for this purpose, and if you lose signal during such a mission, simply note the projected flight plan duration prior to takeoff, and be ready to land the drone five minutes BEFORE the expected ETA, because for flights over 15 minutes long, Litchi errs on the side of caution by providing flight duration estimates that are on average five minutes longer than the actual times you will record when the drone returns to base.

As long as there are no obstacles blocking your drone's view of the sky as it proceeds on Litchi missions, it will follow your pre-programmed flight plan with unerring precision, from launch, until landing.

JJB* Posted at 4-11 01:39
Just give it a try....owning a couple of Mavics.....   

If it looses GPS down in the canyon a altitude limit will be initiatedto your mavic, so you will never be able to fly your drone out (climb) of the canyon.

Would initiating a RTH override that?

crash1sttime Posted at 4-24 09:08
Would initiating a RTH override that?

Manually selected RTH would only work if the drone happens to be within signal range when RTH  is invoked. However, If the battery runs too low for the mission to be safely completed at any point along the flight path, RTH will commence regardless of whether or not the drone is within signal range.  

When creating the flight plan in the Litchi Mission hub, to avoid RTH triggering the instant the drone flies out of signal range regardless of battery duration remaining, remember to select the "continue" menu option as a response to signal loss en-route.  

Also, the action to take on reaching the final (home) waypoint should be menu-selected as "do nothing", and NOT "RTH", or the drone will execute an autoland as soon as it reaches the launch point at the conclusion of its mission.

Thrice I forgot to ensure I did NOT select RTH as the concluding action on arrival at the launch point. and my drone landed on rough ground because I was late stepping outdoors for the landing.   I definitely prefer to manually land the drone, as opposed to trusting the autoland function to descend the craft unto the 4-foot square table I made for the purpose.

Muttley7 Posted at 4-24 10:43
Manually selected RTH would only work if the drone happens to be within signal range when RTH  is invoked. However, If the battery runs too low for the mission to be safely completed at any point along the flight path, RTH will commence regardless of whether or not the drone is within signal range.  

When creating the flight plan in the Litchi Mission hub, to avoid RTH triggering the instant the drone flies out of signal range regardless of battery duration remaining, remember to select the "continue" menu option as a response to signal loss en-route.  

my question was to Captain JJB as he stated that low GPS limits altitude.

crash1sttime Posted at 4-24 09:08
Would initiating a RTH override that?

Hi,

Without GPS, so craft in OPTI mode or ATTI mode a RTH is not possible.....

RTH needs drone compass and GPS.

cheers
JJB

crash1sttime Posted at 4-24 11:29
my question was to Captain JJB as he stated that low GPS limits altitude.

Apologies sir, for my rambling.

Muttley7 Posted at 4-20 10:18
Programming your flight with Litchi will definitely allow your drone to descend into a valley below the launch point elevation.  Litchi allows the setting of negative altitudes, specifically for this purpose, and if you lose signal during such a mission, simply note the projected flight plan duration prior to takeoff, and be ready to land the drone five minutes BEFORE the expected ETA, because for flights over 15 minutes long, Litchi errs on the side of caution by providing flight duration estimates that are on average five minutes longer than the actual times you will record when the drone returns to base.

As long as there are no obstacles blocking your drone's view of the sky as it proceeds on Litchi missions, it will follow your pre-programmed flight plan with unerring precision, from launch, until landing.

How will get Litchi to solve the mission without GPS signal? Oriented using stars? ))))

FB: GeoDrone4K Posted at 4-25 21:52
How will get Litchi to solve the mission without GPS signal? Oriented using stars? ))))

How will get Litchi to solve the mission without GPS signal? Oriented using stars?
Obviously Litchi wouldn't work without GPS, but wat makes you think GPS would be lost?

GPS would only be lost if the canyon is deep and narrow so that most of the sky is not visible.
But a canyon can also be wide and open like the grand canyon.
The OP never commented on what kind of canyon he meant and never came back to give any more details.
The guy suggesting Litchi never made any comment on losing GPS.

Labroides Posted at 4-25 23:52
How will get Litchi to solve the mission without GPS signal? Oriented using stars?
Obviously Litchi wouldn't work without GPS, but wat makes you think GPS would be lost?

I got it...
Anyway, as GPS is based on triangulation, in this type of structures there is a big chance to go down to not enough satellites to have a position...

FB: GeoDrone4K Posted at 4-26 03:07
I got it...
Anyway, as GPS is based on triangulation, in this type of structures there is a big chance to go down to not enough satellites to have a position...

Not necessarily.
If there's plenty of sky still visible, there won't be any problem.

oh I think that would be very risky, I personally would not take that chance.