Satellite theoretical problem

E

ericjoe

Member
My Satellite Setup
Elevation angle. LEO, HEO, GEO satellite. Determine satellite coverage using longtitude, latitude of a position
My Location
NUS, Singapore.
Hey, I am a beginner in satellite. I am not sure whether I have posted my thread in the right section. If i make a mistake, hope the moderator can correct me.

I am preparing for final exam on Satellite topics. I tried to google for this problem below [ as attached ] but it brings me to wrong result.

Can any satellite expert suggest me steps to solve it? Or a proper search key term? Thanks a lot.
 

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hello
problem one need more information. where is this satellite parked??
if the satellite is over europe than alaska will never pick up the signal.
second question
all satellites are in gio stationary orbit 24,000 miles out in space.
so the signal traveling at the speed of light 186,000 miles per second
it will take 24,000 and devide it by 186,000 you get .129 seconds each way.
so a uplink and a down link will take 2 x .129=.258 seconds. total delay
thats all i have for you now
ralph
 
Oh dear am I confusing people again by moving things?? :-lmao
 
Yes, well you confused me but I got there in the end ................ Ralph may still be in limbo of course, wondering where his "where has it gone?" Post has gone! :-lmao
 
ralphmagno said:
hello
problem one need more information. where is this satellite parked??
if the satellite is over europe than alaska will never pick up the signal.
second question.
Click to expand...

[Pedant hat on]
It would be impossible for a satellite to be parked over Europe, unless the Earth gets an axial jolt beforehand.
[/Pedant hat on]

[Pedant hat 2 on]
Some locations in Alaska are able to view geostationary satellites parked in European orbital slots
[/Pedant hat 2 on]
 
hello,
i worded it wrong for sure.
what i was wanted to say was the satellites that are transmitting for europe use are normaly out of range for alaska area.
these birds are parked at the equator i think and being geostationary they are 24,000 miles out.
in his problem 25 degrees elevation is close to the horizon and is low.
ralph
 
The original Europestar 1 satellite (now renamed ) positioned at 45 East was able to provide a single hop link from the UK to the west coast of Australia
 
Even more pedant hat on - Nowhere in problem 1 does it state that the satellite is in geostationary orbit and it is only assumed that the satellite is in an equatorial orbit.
 
Actually its the same with question 2, theoretically they could bounce off the Earth's natural satellite to either location with the associated 1.27 second delay both ways.
 
I hope I'm not too late on this and he took the exam:

Question #1 dose not specify the orbital location of the satellite involved, so we would have to assume that it is a geosync satellite viewable to ground stations in that area, so the answer to the first question would be Tokyo at 48.5 degrees elevation, Halifax at 38.6 degrees and Copenhagen at 26.5 degrees.

Anchorage at 20 degrees, Oslo at 22 degrees and Stockholm at 22.4 degrees fall outside the 25 degree elevation limit.

Question #2 is also kind of a trick question, assuming that the satellite is viewable from both locations, (lets use 125E as it would be right in-between the two locations, as you need a base point to start the calculations) also the distance would be one way as the question states from the satellite to the earth station.

So from 125E to Kuala Lumpur is 36,409 kM (22,623 miles) this equals a 121.6 mS delay.
And from 125E to Sydney is 37657 kM (23,399 miles) this equals a 125.8 mS delay.

Also the correct distance to a true geo orbit is 26,199 miles or 42,164 kM, you have to deduct the earths radius of 3963 miles or 6378 kM (at the equator at sea level) after that.

All GEO orbits are based from the center of the earth out to the satellite, there are 3 GEO orbits, the first is the transit orbit, this is lower then the GEO parking orbit, this is for moving satellites around the Clark belt, (the satellite travels faster in a lower orbit compared to one in a parking orbit) the third is the graveyard orbit, this is higher then the GEO parking orbit, this is where all satellites that have ended their usefulness or have run out of fuel or power end up (if they can move them), in some cases GEO satellites are de-orbited but this is only done on rare occasions as the de-orbiting of a GEO satellite is very tricky, with over 7,000 to 10,000 satellites in a low earth orbit (depending on where you start it off) you could run the risk of actually hitting one.
 
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