Distance spotting and measuring

I we trying to reinvent the wheel here? Would finding someone who worked as an observer in WW2 not yield a result? I would imagine they spent alot of time perfecting a way to judge height.

Try using a protractor or even a sextant.

Also, go and stand outside and watch a plane flying across infront of you (not towards) The angle should stay quiet constant (apart from ALT changes)
Also, if it is approaching you, the angle (if measuring with it in the far distance) doesn’t change much. Its only when it starts coming in closer that the angle will suddenly go through 90 and back out the other side again

From someone who has an engineering degree i would say that the measurement you could get from this is method would yield very inaccurate results,if you set up a crude measurement using a basic protractor,the errors involved are massive,or if you set up a very complex measurement system the speed of the aircraft is too fast in order for you to get consistant measurements.If you compare this to broadly similar applications say advanced weapons,such as smart bombs,the amount of computer power that goes into judging angles & trajectories is immense.

Also the statment that “angle should stay quite constant” for a moving object (aircraft) relative to a stationary object (person) is absolutely incorrect .

I dont mean to burst your bubble,but the challenge of gaining such a measurment is very very complex.

Hope someone can help, cos my head now hurts..

If I assume that an airliner is travelling at 35000 ft and I know that angle that I’m looking at it then can I work out how far away along the ground it is.

I’ve tried looking up sine, cosine and tan (Not used them since school) but totally confused myself :confused:

Cheers
Matt

Dare I bowl a googly by reminding you that the earth is curved…:p

I learned this mnemonic at school (55 years ago):
Some Officers Have Curly Auburn Hair To Offer Attraction
Sine = Opposite over Hypotenuse
Cosine = Adjacent over Hypotenuse
Tangent = Opposite over Adjacent
If you know the angle and the height (the “Opposite” side of the triangle in this case) you can work out the Adjacent side of the triangle (distance along the ground).
Go figure!

hahaha

At school I was taught the name of a great american indian

SOHCAHTOA

and it has remained with me for life 🙁

How in the name of god can you measure the angle of something moving very fast relative to a stationary position?!

Basically what i’m asking is you measure the angle,the maths after that is fairly straight foward.

Try using a protractor or even a sextant.

Also, go and stand outside and watch a plane flying across infront of you (not towards) The angle should stay quiet constant (apart from ALT changes)
Also, if it is approaching you, the angle (if measuring with it in the far distance) doesn’t change much. Its only when it starts coming in closer that the angle will suddenly go through 90 and back out the other side again

Matt

PS The angle to the moon doesn’t change very quickly, but is moving VERY fast to me in a stationary position.

yikes

oh god i woz kicked outta maths at school:D

stands in corridor:(

How in the name of god can you measure the angle of something moving very fast relative to a stationary position?!

Basically what i’m asking is you measure the angle,the maths after that is fairly straight foward.

Tan = Opposite/Adjacent

Opposite = Assumed height of target (35K ft)
Adjacent = Ground Dist

therefore

Adjacent (ground dist) = Assumed target Height/Tan Observed angle

exmpa

I learned this mnemonic at school (55 years ago):
Some Officers Have Curly Auburn Hair To Offer Attraction
Sine = Opposite over Hypotenuse
Cosine = Adjacent over Hypotenuse
Tangent = Opposite over Adjacent
If you know the angle and the height (the “Opposite” side of the triangle in this case) you can work out the Adjacent side of the triangle (distance along the ground).
Go figure!