Flying in a gorge advice?

[twickers14]

Wow this thread demos the brilliance of our Forum. Only 2 things to say/add-FPV came to mind straight away (see Alex Markov’s work here-amazing stuff-in and out of holes and caves), and as you probably know you might include in your careful experiments from turning off the side/ lateral sensors. Others may disagree and happy to be “censored”.

 

[Brojon]

Been there dunnit.
Wind - some really fast winds can develop on canyons and gorges.
I never lost GPS but I made sure to set my RTH height over the highest side.

 

[TxArch DroneGuy]

With the height restriction of no GPS, you may get too far down to fly back out. That has happened to people in slot canyons before. Then you are in for a hike to recover the drone if that's even possible.

The lack of GPS is not the same as loss of signal. If GPS is lost, the. Pilot should still have total command of the flight. However, watch out out for winds in that narrow of a space.

 

[GaryFlorida]

Please don't take anything I said as suggesting you shouldn't do it! It's a hoot!

Just do it incrementally.

I'd fly up and down the canyon at the elevation of the edge first. Watch carefully for any variations in GPS or controller signal strength.

Then drop down 25', and try it again. Lather, rinse, repeat.

Be sure to set your RTH well above the highest point along the rim...

Try it; you'll like it!

Chaosrider makes excellent points. It's all about GPS reception. The lower you go into a canyon, the less of the sky your drone can "see." You will typically lose radio-com, base to drone, before the GPS fails.

Here's the math: You need a minimum of 4 GPS sats in view for it to fully function. Some data says you can get by with THREE, although you lose altitude info with just three. You should have on your display an icon telling you just how many GPS fixes you have. I see commonly 15± when I fly normally.

Launch and hover safely above launch level. See how many GPS sats you can "see." Work from there. Do NOT let it get much below 6 as you slowly descend into the canyon or you will have a long day.

Thanks for listening.
(And yes, when I was a novice, I lost my first drone into a slot canyon 1500' tall and 30' wide.)

 

[Meta4]

Here's the math: You need a minimum of 4 GPS sats in view for it to fully function. Some data says you can get by with THREE, although you lose altitude info with just three. You should have on your display an icon telling you just how many GPS fixes you have. I see commonly 15± when I fly normally.

Those numbers refer to a basic hand held GPS unit way back in the early days of GPS when there was only one GPS system .
And DJI was a little different even back then.
Here's the DJI math

A DJI drone won't enter P-GPS (Normal) Mode without a minimum of 6 satellites.
But the satellites have to be spread across a large enough section of the sky to provide good location data.
If your drone can only see sats in a narrow band of the sky or just a small area, even if the number of sats is above the minimum, you still won't get good location data.

Modern drones are acquiring signals from two or three different satellite systems, so there are many more sats in the your sky and you will need significantly more than the minimum number above before you have sats from a wide enough area to give good data.
With the latest models using three sat systems, that number could be 15-22 or more before your drone will have good enough data to go to Normal Mode and record a home point.

 

[MavicAir2Marc]

The lack of GPS is not the same as loss of signal. If GPS is lost, the. Pilot should still have total command of the flight. However, watch out out for winds in that narrow of a space.

You have command of the aircraft but it limits your height and distance in that mode. If you are farther down than that distance, the aircraft won't climb higher than the limit to get you out unless you pick enough satellites up at that height to return to GPS mode.