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How do drones work?

Posted: Wed Sep 25, 2013 8:00 pm
by vet111s
Ok, this has been bothering me for a while.
Drones are flown apparently from airbases via a geostationary satellite. Now, if we assume it takes about 0.25s for radio waves to travel to and from a satellite (according to Wikipedia) then info airbase-satellite-drone-satellite-airbase then takes about half a second plus whatever decoding etc is required. Add to that an average reaction time of 0.2s we're getting towards 1s. Now this is ok in a high level, almost expendable drone. However Boeing have now retrofitted the technology into 8 f16s. Given the lag time, these are surely going to be useless in any kind of a dog fight or attack by anti-aircraft missiles if top gun is to be believed. They're a lot more expensive than drones and I'm struggling to see the advantage.
Maybe just a bit of willy waving on the part of the yanks?
Or am I over thinking it?

Ali

Re: How do drones work?

Posted: Wed Sep 25, 2013 8:04 pm
by Kugaman1
JTIDS

Andy

Re: How do drones work?

Posted: Wed Sep 25, 2013 8:49 pm
by vet111s
Excellent, that's put my mind at rest!

Cheers :thumbsup

Re: How do drones work?

Posted: Wed Sep 25, 2013 9:13 pm
by robin
Actually, unless the military boys have found a way of breaking the speed of light then it will take approx 0.4-0.5s round trip.

Frequency/spectrum/bandwidth are nearly irrelevant to the delay (but not quite, because the refractive index of air is not quite 1).

Cheers,
Robin

P.S. But if it's not going via geo-stationary satellite then it does depend on point-to-point distance of whatever nodes it has to traverse to get from base to drone and back. Even so the circumference of the earth is 45,000km so if you need to get from USA to Afghanistan and back, you're still looking at pretty much the same time.

Re: How do drones work?

Posted: Wed Sep 25, 2013 9:37 pm
by tut
Can't think in metres Robin, but the geo satellite would be at around 22,500 miles, speed of light is 186,000 miles/sec, divided by 45,000 = 0.25 secs.

tut

Re: How do drones work?

Posted: Thu Sep 26, 2013 7:34 am
by Scuffers
vet111s wrote:Ok, this has been bothering me for a while.
Drones are flown apparently from airbases via a geostationary satellite. Now, if we assume it takes about 0.25s for radio waves to travel to and from a satellite (according to Wikipedia) then info airbase-satellite-drone-satellite-airbase then takes about half a second plus whatever decoding etc is required. Add to that an average reaction time of 0.2s we're getting towards 1s. Now this is ok in a high level, almost expendable drone. However Boeing have now retrofitted the technology into 8 f16s. Given the lag time, these are surely going to be useless in any kind of a dog fight or attack by anti-aircraft missiles if top gun is to be believed. They're a lot more expensive than drones and I'm struggling to see the advantage.
Maybe just a bit of willy waving on the part of the yanks?
Or am I over thinking it?

Ali
yours assuming they 'fly' these drones real time...

they don't, the drone flys itself, all the 'pilot' does is 'manage' it, as in tell it where to go, the finer points of how it maintains stable flight etc are done within the drone.

Much like the flight management systems of airliners now, the pilots just programme them, they then fly the plane..

the only exception to this is that a 'local' pilot can and and take off the drone by conventional radio control before handing it over to the 'remote' pilot.

Re: How do drones work?

Posted: Thu Sep 26, 2013 8:35 am
by Corranga
tut wrote:Can't think in metres Robin, but the geo satellite would be at around 22,500 miles, speed of light is 186,000 miles/sec, divided by 45,000 = 0.25 secs.

tut
Would it be 45,000 miles as you have to get there and back, or is 22,500 miles the return trip? I can't comprehend that amount of miles in relation to how far away a satellite would be :blackeye


I'd presume that the F16s are for decoy / protection reasons.
I'd also assume that there is some clever engagement AI in these things..

You send up X number of say, bombing drones and a squad of F16s to escort them. The enemy sees a bunch of slow heavy bombers, and a bunch of fast fighters to protect them.
What do you attack first?

If they go for the bombers, then the AI drone F16s take them out.
If they go for the F16s, your bombers get away and make their bombing run, whilst someone more local on the ground potentially takes remote control, or the AI goes into evade mode.

Either way, you've saved lives of some very useful pilots, so it's a win right?

Chris

Re: How do drones work?

Posted: Thu Sep 26, 2013 8:45 am
by tut
A satellite that is in a geostationary orbit around earth is around 22,500 miles high, so for the radio signal to go from the operator to it then back to the drone is 45,000 miles.

tut

Posted: Sun Sep 29, 2013 1:23 pm
by Sanjøy
Balloons with fricking lasers. It's the future. High frequent bank reading using POS already.