10 Satellites and lost GPS

[Whirlygig]

...As for multiple path issues, it is a real problem and should do whatever you can to migrate the issue, eg not fly in wooded area, tall buildings, large body of water...

yt, i understand the multiple path or bouncing signal problem that can arise flying close to trees, buildings etc. But, why would flying over large body of water tend to cause gps problems?

 

[Whirlygig]

Number one sats has nothing to do with the quality of the signal...

can you explain this? I had also been assuming that taking off with 20 sat lock was better than taking off with 10 sat lock because it would be less prone to disconnect mid flight. I see how flying close to buildings or large metal objects could disrupt and disconnect signal but what factors might cause it at altitude in the wide open?

 

[Pedals2Paddles]

You can have a perfectly stable, solid, and accurate position fix with 6 satellites just as you can with 9,14, or 20. And it goes both ways. You can have a crappy, useless, drifting position position fix with 6 satellites just as you can with 9, 14, or 20. Put another way, just because you "only have 6 satellites" doesn't mean your position fix is any worse than it would be with more satellites. And just because you have 20 satellites, doesn't mean your position fix will be better.

There is a lot that goes into determining if a position fix is accurate and usable for a drone. Number satellites is one of many factors that goes into it. And it is really one of the least important factors of them all, and has very little direct correlation to accuracy. It's a LOT more complicated and strict than your Google Maps or the GPS in your car, which makes assumptions that don't matter.

Where a very high satellite count is useful, is it's ability to cope with satellites moving in and out of view as the drone moves around. The more you have, the more you can lose. This isn't making a "better signal" or making it more accurate. It makes it more redundant.

 

[Frank Foster]

Interesting thread. Question for the more informed, does the Solo use HDOP strength as the requirement for a lock, or the number of sats?

 

[Jubalr]

#sats and HDOP are but a portion of what is looked for. When the Solo was released in 2015 it was the following, with some of this changing a little in FW updates since..

The following requirements define a GPS lock: Reported horizontal position accuracy < 16 ft. (5 m) Reported speed accuracy < 2 mph (1 m/s) Number of satellites ≥ 6 Difference between GPS and inertial navigation vertical velocity < 2 mph (1 m/s).

 

[Whirlygig]

yt, i understand the multiple path or bouncing signal problem that can arise flying close to trees, buildings etc. But, why would flying over large body of water tend to cause gps problems?

I've done some reading on some of the other drone forums and see this question asked and answered a bunch. As near as I can tell, the answer is that flying over water is NOT a problem in and of itself for either wireless or gps connections end of story. The problem is only psychological unless you are flying below 20' with a ground sensor which solo does not have. Anyone disagree?