Hi,

The minmum Sats Locked on UAV Forecast mentioned 12 for a safe flight!
I just wanted to double check with you guys how many would be the minimum including GLONASS Sats? UAV is right?

thanks

The minimum number of satellites for reliable positioning depends on their location on the horizon and height.

“The minimum sats for a safe flight”

It is possible to fly with 4 satellites, but not recommended the number for safe good gps lock is 6, your receiver receives two kinds of satellites primarily, glonass and gps , so in order to guarantee 6 your count on your telemetry should read minimum 11 which guarantees a minimum of 6 of one type.
Sometimes a better gauge is to use graph bars next to number count on your telemetry, if you have 4/5 bars lit up white you have good gps lock, fo me this is more dependable to use .
Hope this helps.

You can get a good 3D fix with a handheld GPS with 4 sats.
DJI won't be in GPS mode unless you have a bare minimum of 6.
But you won't always get GPS lock with the bare minimum because the sats have to have a suitable spread, not bunched or in a line.

But you can ignore UAV forecast for GPS sat numbers because wherever you go, you will always have more sats than you need, as long as you are out in the open where the GPS antenna has a clear view of most of the sky.

You can also ignore the K index in UAV Forecast.
It's never made any difference to anyone's drone flying.

Hi ARTPH,

DJI drones (the last few years for sure, did not check the older types) uses a chip wich simultaneously uses the GPS and GLONASS satellites.
In DAT files you can see the total and seperate number of sats to have a lock.
Any summing up to 6 -7 sats GPS/GLONASS or more will do for a flight. But for a safe flight?
More satellites is better ofcourse, and what we do not see from numbers is where the receiving sats are positioned in the sky. Widely spread * is better than close to each other.
Not only the numbers are important, but the reception of satellites as well.Less than 3 bars indicated means less accurancy for a stabilized hover/flight.

* better for positioning accurancy and chance of loosing more sat at once is less. So in urban flying situation you want to have more (chance of loosing sates when they are hidden after a building etc) than flying in a flat wide open area.

Conclusion ; wait for enough satellites (where do i fly...), check the reception value and check if homepoint is recorded (and checked on the map).

Happy many landings,
cheers
JJB

It’s wrong to say you need more satellites in an urban area, in fact it’s almost not possible to get more satellites in this kind of environment as it is under cover of trees, for those obvious reasons,  what you need is better signal not more satellites, video below will explain .

hallmark007 Posted at 2-23 04:35
It’s wrong to say you need more satellites in an urban area, in fact it’s almost not possible to get more satellites in this kind of environment as it is under cover of trees, for those obvious reasons,  what you need is better signal not more satellites, video below will explain .

https://youtu.be/i-CnCM0iEpk

Thanks for the video links and the information you provided earlier in the thread.  I watched all three videos in the series and they were extremely helpful.

red squirrel Posted at 2-23 06:11
Thanks for the video links and the information you provided earlier in the thread.  I watched all three videos in the series and they were extremely helpful.

No problem those videos are extremely helpful for all drone flyers .

Fly safe .

hallmark007 Posted at 2-23 04:35
It’s wrong to say you need more satellites in an urban area, in fact it’s almost not possible to get more satellites in this kind of environment as it is under cover of trees, for those obvious reasons,  what you need is better signal not more satellites, video below will explain .

https://youtu.be/i-CnCM0iEpk

Very informative video.  Thanks for sharing.

Edit: Went back and watched over 2 videos in this series.  Also, very informative with useful information.

hallmark007 Posted at 2-23 04:35
It’s wrong to say you need more satellites in an urban area, in fact it’s almost not possible to get more satellites in this kind of environment as it is under cover of trees, for those obvious reasons,  what you need is better signal not more satellites, video below will explain .

Well, if you have 7 sats and GPS lock in urban area the chance of loosing 1 or 2 (with its consequences) is more likely to happen than flying with 7 satellites in an wide open area.
That is my point i wanted te make.

This is a simple way of explaining that its better to have or wait for more, if possible ofcourse to receive more, in an urban or any other area like you described to start a flight. Better signals always better but when a satellite is obscured by buildings etc than this signal is not there to receive or even worse its reflection will hamper the overal receiving signals.  
Shall we not talk about 6 of each GPS or GLONASS anymore....

cheers
JJB

JJB* Posted at 2-23 06:32
Well, if you have 7 sats and GPS lock in urban area the chance of loosing 1 or 2 (with its consequences) is more likely to happen than flying with 7 satellites in an wide open area.
That is my point i wanted te make.

I think you are misunderstanding what simultaneously means, very difficult to rub your tummy and pat your head at the same time, so I know exactly what I mean and it’s correctly demonstrated in the video and emphasis on numbers in urban areas not best advice, so I think OP has now best of all information and correct understanding, I realize you are not accustomed to changing your position, so best leave it there.

As some have mentioned here and is discussed in Mad's video, it is more specifically the number of bars next to the satellite indicator that is more important than the number of satellites.  Generally speaking, anything less than 4 bars means it really doesn't have a good fix on your position and your risk of a bad outcome significantly rises.

hallmark007 Posted at 2-23 06:57
I think you are misunderstanding what simultaneously means, very difficult to rub your tummy and pat your head at the same time, so I know exactly what I mean and it’s correctly demonstrated in the video and emphasis on numbers in urban areas not best advice, so I think OP has now best of all information and correct understanding, I realize you are not accustomed to changing your position, so best leave it there.

hahah  silly as always Hallmark....

reading your post OP had the wrong info.

"minimum 11 which guarantees a minimum of 6 of one type " is simply not correct,. just learn to read DAT files and understand other peope with more knowledge.

Agree with you, leave it there. Forum users with some common sense and understanding will value your postings....

cheers
JJB

JJB* Posted at 2-23 08:20
hahah  silly as always Hallmark....

reading your post OP had the wrong info.

As I said you seem to find it almost impossible to admit your giving out wrong info, twice this week you gave out almost disastrous information to users almost sending them away thinking they were the cause of their crash and again here, I’m thankful that other members will openly question your assessments, now go away and find out what simultaneous means and keep it to yourself .
I'd appreciate now if you look at your own comments before commenting on mine .

When you notice @hallmark007 and @JJB* bickering
Should we move on ?

A thing I do is to check what the compass does while the AC is on the ground, that way you can see if there's magnetic interference, if the bar is as short as possoble and green. There's no interference. The longer the bar gets the more interference you have but not enough to say it have magnetic interference, if its yellow move away from that site if its red,.. Well you know what to do, Just move the drone to a different location till the bar gives the best result. You can also use the drone to see where the best place is to launch from. I found out where I have lots of rebar underground using the drone.

this is an amazing