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Distance/Height formula ?

Prmath

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#1
Is there a formula to figure how Far drone can go and what Altitude it needs to be for Line of Sight ?
TIA, guys
 

dylanthecat

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#2
You would need to know heights of trees and buildings along the flight path. For typical drone distances, you would alway be in LOS at any normal flying altitude.
 

Jerry

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#3
Forgive me, but I’m struggling with your question .. and it’s validity .. line of sight is an imaginary line that stretches between your eye and the object that you are looking at.. ..
 

zocalo

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#4
Like Jerry I'm not sure what you mean. Line of Sight just means you can physically see the drone so depends on visible conditions, obstructions, and your eyesight. However, in some scenarios, you can also use a spotter with a scope, so that can be a pretty long way beyond the Mk1 eyeball's range.

Best I can think of is given a horizontal distance, X, and an altitude, Y, what is the direct distance. If so, that's basic trig - calculating the hypoteneuse of a right angled triangle:

Z = sq.root (X^2 + Y^2)
 

WithTheBirds

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#5
Like Jerry I'm not sure what you mean. Line of Sight just means you can physically see the drone so depends on visible conditions, obstructions, and your eyesight. However, in some scenarios, you can also use a spotter with a scope, so that can be a pretty long way beyond the Mk1 eyeball's range.

Best I can think of is given a horizontal distance, X, and an altitude, Y, what is the direct distance. If so, that's basic trig - calculating the hypoteneuse of a right angled triangle:

Z = sq.root (X^2 + Y^2)
VLOS mean you can visually see it- LOS means there is an unobstructed path between transmitter and receiver.
 

rangemaster728

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#6
However, in some scenarios, you can also use a spotter with a scope, so that can be a pretty long way beyond the Mk1 eyeball's range.
The only scenario (in the USA) that might allow a visual observer to use a scope (i.e., binoculars, etc.)is a Part 107 operation with an approved waiver of 14 CFR 107.31:

107.31 Visual line of sight aircraft operation.
(a) With vision that is unaided by any device other than corrective lenses, the remote pilot in command, the visual observer (if one is used), and the person manipulating the flight control of the small unmanned aircraft system must be able to see the unmanned aircraft throughout the entire flight in order to:

(1) Know the unmanned aircraft's location;

(2) Determine the unmanned aircraft's attitude, altitude, and direction of flight;

(3) Observe the airspace for other air traffic or hazards; and

(4) Determine that the unmanned aircraft does not endanger the life or property of another.

(b) Throughout the entire flight of the small unmanned aircraft, the ability described in paragraph (a) of this section must be exercised by either:

(1) The remote pilot in command and the person manipulating the flight controls of the small unmanned aircraft system; or

(2) A visual observer.
 

zocalo

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#7
The only scenario (in the USA) that might allow a visual observer to use a scope (i.e., binoculars, etc.)is a Part 107 operation with an approved waiver of 14 CFR 107.31:
Yes, that's why I said "some scenarios". It's the same here in the UK, FWIW, but not all countries require unaided VLOS, or even VLOS at all for that matter - just make sure you can keep track of where the drone is using the map in the App and camera before you try it though!

Not any of the discussion over LOS and drone legislation helps figure out OP's question though; I'm still not sure if it's just about the distance calc or some kind of max theoretical range query...
 

rangemaster728

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#8
Agreed...that being said, with respect to the OP’s question the answer is likely:

No...while there are formulas for radio LOS and Visual LOS at the end of the day VLOS depends on the size/conspicuity of the drone, the visual acuity of the pilot/observer and weather/ambient lighting conditions.

The practical answer on any given day and time is to launch, ascend and fly away until you can barely see the drone.

The cautionary note here is when it is very far away all it takes is a glance down at the flight display and ‘oops..where did it go?’

This is why I usually run strobes on the bird as it greatly increases how far away I can fly and still have effective visual contact.
 

BerndM

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#9
I can easily see mine at 1000 feet assuming that it is above the ground background with unobstructed sky behind it.
HOWEVER.....if I take my eyes off it for even a few seconds, it is highly unlikely I will find it again until it is much closer.
 

zocalo

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#10
I can easily see mine at 1000 feet assuming that it is above the ground background with unobstructed sky behind it.
HOWEVER.....if I take my eyes off it for even a few seconds, it is highly unlikely I will find it again until it is much closer.
Yeah, at that range you really need a reference point to help you locate it again, or better yet a strobe attachment. Bringing it to a temporary hover directly above a fixed object on the horizon will usually help you reacquire it, especially if you are good at estimating the vertical angle you need to look along as well. Failing that, a couple of other tricks I've found helpful are pointing the camera straight down to get a better idea of where it might be located in relation to you, and on sunny days if you just spin it on the spot you might also be (very!) lucky enough to find an angle where it catches the sunlight and gives off a flash of light.
 

Prmath

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#11
I can easily see mine at 1000 feet assuming that it is above the ground background with unobstructed sky behind it.
HOWEVER.....if I take my eyes off it for even a few seconds, it is highly unlikely I will find it again until it is much closer.
Agree 100% and with these old eyes........ it’s worst.
 
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#13
Ham radio enthusiasts have that exact calculator. Not sure where I found it but I have used it before. Its for calculating line of site for a given antenna height. I used it when I hiked Mt Whitney to see if my VHF radio would hit our club repeater 350 miles away.
 

rfc

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#15
If you were at sea in calm conditions, at 1 mile, the A/C would need to be .667' high to "see" it.
At 2 miles: 2.67'
At 3 miles: 6 feet, and
at 4 miles, you'd need 10.7' of altitude to be above the curvature of the earth!:D
If there are any waves at all, it would vary depending on whether you're at the top of a wave crest.
 

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