What is the path loss formula for a drone-to-ground communication?

[Simon de Boer]

How can I estimate the propagation loss between an unmanned aerial vehicle (UAV) or drone, and user equipment (UE) on the ground? is it safe to assume a line-of-sight scenario? how about the drone's altitude? is there a specific air-to-ground formula I can use?

 

[iaincaradoc]

Here's a link to a free space path loss calculator. Keep in mind that *anything* within the Fresnel zone is going to change the calculation - some things more than others.

Free Space Path Loss Calculator (FSPL) - everything RF

www.everythingrf.com

 

[slup]

...is it safe to assume a line-of-sight scenario?

Think you're overthinking this, what matter most is purely unobstructed line of sight then distance ... & RC-AC signal strength.

If you aren't flying from flat farmlands stretching miles & miles out you will always have something that can obstruct the LOS close to you ... a tree line or houses or something similar. Get an app in your phone so you can measure how many degrees it's from your position on ground to the top of the obstruction ... then use trigonometry (you have apps for that also) to calculate how far out you can fly on a certain height or how high you need to fly to reach a certain distance out until the LOS becomes obstructed & the connection becomes sketchy.

 

[iaincaradoc]

Think you're overthinking this, what matter most is purely unobstructed line of sight then distance ... & RC-AC signal strength.

If you aren't flying from flat farmlands stretching miles & miles out you will always have something that can obstruct the LOS close to you ... a tree line or houses or something similar. Get an app in your phone so you can measure how many degrees it's from your position on ground to the top of the obstruction ... then use trigonometry (you have apps for that also) to calculate how far out you can fly on a certain height or how high you need to fly to reach a certain distance out until the LOS becomes obstructed & the connection becomes sketchy.

"Line-of-sight" is not the only issue at hand. As I mentioned, anything within the Fresnel zone can affect signal attenuation.

At 2.4GHz, at one mile, the Fresnel zone is about 46 feet in diameter (just a hair over 14 meters.)

At 2.4GHz, at two miles, the Fresnel zone is about 64 feet (20 meters) in diameter.

And then there's the (probably false) assumption of a unity antenna at both ends.

Foliage is one thing that causes surprisingly high attentuation at 2.4GHz.

 

[slup]

...anything within the Fresnel zone can affect signal attenuation...

Pure technically I agree with you ... but in real life flying Fresnel zone calculations isn't anything that anybody will do if not trying to sneak in between objects & maintaining the strongest possible signal.

In an ordinary flight it's enough to remember that getting thing's in between the RC & AC will degrade the connection quality major.

As said ... no need to overthink it.

 

[Stealth01]

Think you're overthinking this, what matter most is purely unobstructed line of sight then distance ... & RC-AC signal strength.

If you aren't flying from flat farmlands stretching miles & miles out you will always have something that can obstruct the LOS close to you ... a tree line or houses or something similar. Get an app in your phone so you can measure how many degrees it's from your position on ground to the top of the obstruction ... then use trigonometry (you have apps for that also) to calculate how far out you can fly on a certain height or how high you need to fly to reach a certain distance out until the LOS becomes obstructed & the connection becomes sketchy.

Really funny you mention this... Was flying out over farm land at 145 feet altitude and started experiencing a break up in video followed by a “RC Lost Signal”... Oh Boy!! What saved me was I had started a climb when the video started breaking up and I suddenly regained reception... Long story short I did just what you suggested, took distance and altitude from screen recording and triangulated the drones position... Which placed a very large barn with a metal roof right in my line of sight!! Lesson learned... Altitude is your friend!

 

[Zbip57]

How can I estimate the propagation loss between an unmanned aerial vehicle (UAV) or drone, and user equipment (UE) on the ground? is it safe to assume a line-of-sight scenario? how about the drone's altitude? is there a specific air-to-ground formula I can use?