Satellite coverage question.

[twickers14]

Like many of you I use UAV Forecast for pointers re flying conditions and have noticed that Estimated Sats Locked in my area has been below the threshold I have set (based on advice here-min 12) for some days-at the same time of the day. I actually went out to fly when it said I had only 10 locked. When I set up from launch pad it showed 15 on my RC and all was well. Does anyone know if this “coverage” is temporary or permanent?

 

[old man mavic]

in reality you only need 3 Sats to get a triangulation to pinpoint your position ,but you will notice that with the latest drones such as the Mini 3 with the three Satellite constellations available its often possible to have up to as many as 33 Sats locked
i have also noticed that my Mini 3 pro seems to wait till it has 12 locked before i get the home point message to allow take off, where as the MPP and MM will announce it with 9 or so and i get a maximum of around 15 to 18 with those drones as they only use two constellations as has been mentioned before UAV Forecast is a prediction based on many factors and not a true representation of the exact area you are at

 

[Meta4]

Like many of you I use UAV Forecast for pointers re flying conditions and have noticed that Estimated Sats Locked in my area has been below the threshold I have set (based on advice here-min 12) for some days-at the same time of the dayView attachment 160770. I actually went out to fly when it said I had only 10 locked. When I set up from launch pad it showed 15 on my RC and all was well. Does anyone know if this “coverage” is temporary or permanent?

You don't mention which drone you use.
Some use two sat constellations and some So different drones would show different numbers of sats when flying in the same area.
If you've left UAV forecast on default settings and not configured it to suit your drone, the sat numbers it shows might be irrelevant.

There's really no need to bother what number of sats UAV Forecast shows anyway.
No matter where you fly and when, there will always be many more satellites in your sky than you need.

A few details of GPS basics that frequently confuse drone flyers.

in reality you only need 3 Sats to get a triangulation to pinpoint your position

A basic GPS receiver requires a minimum of 4 sats to obtain a 3D fix.
DJI have a higher standard and require a minimum of 6.
But with multiple satellite constellations you have many sats close to each other in the sky and you will likely need more than 6 before the receiver has a suitable spread.

i have also noticed that my Mini 3 pro seems to wait till it has 12 locked before i get the home point message to allow take off, where as the MPP and MM will announce it with 9 or so

The flight controller doesn't record a home point at any particular number of sats.
It's waiting until the spread of sats will provide good location data.

 

[twickers14]

That’s so helpful thanks. I fly a Mavic Air 2. Maybe I should revisit my minimums (I have set my own parameters on UAVF) and thus far they have been fine. One is always too conservative on whether conditions are OK to go but I just don’t fancy a fly away etc. On sats it’s all on the RC anyway and in most cases wind, rain cloud cover are common sense. Happy flying.

 

[Meta4]

Maybe I should revisit my minimums (I have set my own parameters on UAVF) and thus far they have been fine.

Your drone does this for you (and as I mentioned above, the number of sats is not what matters, the spread is).
Watch the satellite icon on the top of your flying screen.
When you startup and satellites aren't good enough, the icon and number is red.
As the drone picks up more sats and the spread improves, the icon changes to a yellowish.
When the icon changes to white, the flight controller has determined that you have plenty of sats and the spread is suitable for reliable location data and it has recorded a home point.

 

[twickers14]

in reality you only need 3 Sats to get a triangulation to pinpoint your position ,but you will notice that with the latest drones such as the Mini 3 with the three Satellite constellations available its often possible to have up to as many as 33 Sats locked
i have also noticed that my Mini 3 pro seems to wait till it has 12 locked before i get the home point message to allow take off, where as the MPP and MM will announce it with 9 or so and i get a maximum of around 15 to 18 with those drones as they only use two constellations as has been mentioned before UAV Forecast is a prediction based on many factors and not a true representation of the exact area you are at

Thanks OMM. I have to admit that on occasions (very few I hasten to add), in my excitement to get up and away I forgot to wait for “The Home Point Has Been Updated” so I was flying “blind” so to speak. I live to tell the tale but not to be recommended!

 

[Meta4]

I have to admit that on occasions (very few I hasten to add), in my excitement to get up and away I forgot to wait for “The Home Point Has Been Updated” so I was flying “blind” so to speak. I live to tell the tale but not to be recommended!

Your drone will record a homepoint wherever it is, as soon as it gets reliable GPS location data.
Usually that would be somewhere close to where you launched.

Except in certain situations that's usually not a big deal.