How many satellites are needed for RTH to work.

[grahamjohnson10]

Please could someone let me know the minimum number of satellites are needed for RTH to work.

 

[phantomi]

Not sure but you should have them if air-borne...

 

[Meta4]

Please could someone let me know the minimum number of satellites are needed for RTH to work.

There is no fixed number that guarantees a good GPS location fix but DJI drones won't be in P-GPS mode with less than 6 sats.
But even with 6 (or more) sats you won't have P-GPS unless you also have good satellite geometry.

 

[gnirtS]

Its not the number of satellites, its the geometry of the visible satellites.

If you only have a small section of sky visible GPS is going to be inaccurate or even not work at all. The same number of satellites spread more favourably around the sky will yield far better accuracy.

 

[old man mavic]

because it has GPS and glonass you should be getting anywhere from 10 to 20 ,but as Meta4 said this depends on many factors including the surroundings you are flying in,when the mini has enough to fly safely it will say ready for take off

 

[Thomas B]

All above is true... but of note, on a recent hike into the Siphon Draw, a narrow canyon in the Superstition Mountains, I had no problem with having adequate number and spacing of positioning satellites.

 

[gnirtS]

I get it a lot in narrow canyons, waterfalls, forests etc.

It looks OK but the error circle is large and worst case, jumps in and out of P-GPS mode causing the drone to move wildly.

Thats why my M2P has now been altered to give me ATTI mode so i an still fly without it moving all over the place due to unfavourable satellite geometry.

 

[ZX14-R]

I think Min of three for triangulation.

 

[Thomas B]

I think Min of three for triangulation.

Interesting... I thought it was 6, or maybe 8.

 

[Meta4]

I think Min of three for triangulation.

Interesting... I thought it was 6, or maybe 8.

If you use a handheld GPS unit on the ground, it will require a minimum of four sats to get a 3D fix.
Sat geometry might mean you still can't get a good fix with the minimum number.
DJI require a minimum of 6 sats but you still might need >6 because of sat geometry.

 

[Keule]

Please could someone let me know the minimum number of satellites are needed for RTH to work.

According to DJI's GPS health scale:

Level0: The GPS has almost no signal, which is very bad.
Level1: The GPS signal is very weak.
Level2: The GPS signal is weak. At this level, the aircraft's go home functionality will still work.
Level3: The GPS signal is good. At this level, the aircraft can hover in the air.
Level4: The GPS signal is very good. At this level, the aircraft can record the home point.
Level5: The GPS signal is very strong.

 

[gnirtS]

It'll still *work* but with nothing like the accuracy. You maybe 20m+ or more from the launch point.

The GPS bar shows the GPS quality which is far more useful than a number of satellites.

 

[Keule]

The GPS bar shows the GPS quality which is far more useful than a number of satellites.

That's what I posted in #11. The GPS Health/quality levels according to DJI's definition.

Source: DJIGPSSignalStatus

 

[Meta4]

The good news is that wherever you fly, if you are out in the open with a clear skyview of most of the horizon, you'll always have more than enough satellites.