Flying over deep canyons risk

[AMann]

As I said - it's typically 2 - 3 meters with the modern chips and > 12 satellites. That's not really surprising since the theoretical average vertical error is 1.5 times the horizontal error. In the air these receivers typically do very well because they have such a good sky view.

But you have to admit that a $100 electonic barometric altimeter can easily beat that for measuring relative elevation...

By the way, do you know to what degree the barometer on a Maveric is accurate to? (in terms of relative measurement).

 

[sar104]

But you have to admit that a $100 electonic barometric altimeter can easily beat that for measuring relative elevation...

By the way, do you know to what degree the barometer on a Maveric is accurate to? (in terms of relative measurement).

Ah - that's an issue of resolution rather than accuracy. The barometer is definitely going to be more robust for detecting relative changes in altitude, especially with fewer than optimal satellites. And the barometers themselves have good accuracy in terms of pressure measurement - it's the necessary assumptions about the temperature and density of the atmosphere as a function of altitude that result in poor absolute accuracy.

The DJI pressure sensors are supposedly able to resolve pressure changes equivalent to around 20 cm vertical.

 

[AMann]

Ah - that's an issue of resolution rather than accuracy. The barometer is definitely going to be more robust for detecting relative changes in altitude, especially with fewer than optimal satellites. And the barometers themselves have good accuracy in terms of pressure measurement - it's the necessary assumptions about the temperature and density of the atmosphere as a function of altitude that result in poor absolute accuracy.

The DJI pressure sensors are supposedly able to resolve pressure changes equivalent to around 20 cm vertical.

Thats not bad for flying upslope from a starting point- I’m still hoping to get a good USGS topomap background map with elevation notes that works on CS or iPads...

 

[sar104]

Thats not bad for flying upslope from a starting point- I’m still hoping to get a good USGS topomap background map with elevation notes that works on CS or iPads...

Gaia GPS. Absolutely unrivaled for that purpose.

 

[AMann]

Gaia GPS. Absolutely unrivaled for that purpose.

Gaia GPS. Absolutely unrivaled for that purpose.

Ah, that is a good program. I use TopoMaps- no subscription fee and it downloads high resolution USGS quads, but I meant a topo as a background map for DJI Go 4 that shows contour lines. Have you seen such a way to do that?

Sort of on topic here, such a map can also help OP fly that canyon...

 

[sar104]

Ah, that is a good program. I use TopoMaps- no subscription fee and it downloads high resolution USGS quads, but I meant a topo as a background map for DJI Go 4 that shows contour lines. Have you seen such a way to do that?

Sort of on topic here, such a map can also help OP fly that canyon...

Right - I misunderstood. DJI GO 4 is limited to Apple or Google maps.

 

[AMann]

Right - I misunderstood. DJI GO 4 is limited to Apple or Google maps.

Are there any other control programs currently for CS or IOS that will?

 

[sar104]

Are there any other control programs currently for CS or IOS that will?

I've only used the DJI GO and Pilot apps, plus Litchi. Those do not have that option.

 

[AMann]

I've only used the DJI GO and Pilot apps, plus Litchi. Those do not have that option.

For the SAR work you do, I’d think that would be a valuable tool too! Hey- thanks for answering my questions, very helpful as usual!

 

[sar104]

For the SAR work you do, I’d think that would be a valuable tool too! Hey- thanks for answering my questions, very helpful as usual!

I fly automated mostly, and the missions are planned using GE, so it's less of an issue. It would be nice though.

 

[kilomikebravo]

When we backpack, I often just use my altimeter to pinpoint my location on a topo

Amann: But where do you get the local baro setting from? <smiling and just kidding> I've never jumped from a perfectly good airplane so I have never seen a portable altimeter like those used by skydivers. How accurate would you say yours is since a decent high or low pressure change could easily induce a 50-100' error?

Remember, when going from high to low, look out below. <grin>

 

[AMann]

It’s easy to reset in the backcountry - trail crossings are good indicators, benchmarks, peaks, etc., pretty much any landmark you can find on the topo since I’m carrying a real topo map so it’s easy to see what elevation we should be at each morning...

 

[kilomikebravo]

Ahhhh...that explains the correct altimeter setting, I didn't think you had those charts and were looking for same. Guess I need to read a bit more closely. I was going to suggest calling up an ATIS or FSS nearby for the altimeter setting but since you have an exact reference, that's perfect.

 

[AMann]

Ahhhh...that explains the correct altimeter setting, I didn't think you had those charts and were looking for same. Guess I need to read a bit more closely. I was going to suggest calling up an ATIS or FSS nearby for the altimeter setting but since you have an exact reference, that's perfect.

What’s your other bird? Sounds like you have one you sit in, too

 

[kilomikebravo]

Well, it used to be an Airbus A-300 but I retired. Honestly, the M2P is more fun to fly...er, MOST of the time.

 

[cloneme]

I am a new owner of a mavic 2 pro and have flown it a few times successfully . I would like to fly it over my daughter's property (340 acres) but one boundary is a sheer cliff some 300m to a river and we would like to be able to get a video over the edge. My question is, would flying over a sudden drop which would mean the drone's senses that the height has gone from say 100m to 400m would there be a correction and the drone would drop?

This is the Canyon I was talking about

 

[Meta4]

This is the Canyon I was talking about

Fly out from the edge and your drone won't even notice.
The comments about the dangers of updrafts (above) are overstated.
That would only be an issue if there are gusty winds and you'd be well aware of that if it was an issue.

 

[PWIdmayer]

Jealous of where you get to fly !!! Dang

 

[bronze661]

No - the aircraft VPS system may notice that the ground has vanished, but the aircraft references its altitude to the home point, not to the ground it is flying over. It will be unaffected by flying over a 300 m cliff. I'd watch out for up- or down-drafts though.

What if this was a Litchi mission with the "above ground" box checked?

 

[FoxhallGH]

This is the Canyon I was talking about

Incredible place to fly ... I don't know if you are new to drones in general, or just new to the Mavic 2 - but one thing to think about here is that it's going to be a long and difficult walk to get the Mavic back if it goes wrong! So get 100% familiar with you pre-flight checks and settings before your fly off into that space!