# Satellite Comm

Hii guys.I have this problem.Can anybody help me on this.tq

## Homework Statement

A satellite is in a circular polar orbit at a height of 870 km, the orbital period being approximately 102 min. The satellite orbit passes directly over a beacon at sea level. Assuming an average value of earth’s radius of 6371 km determine approximately the fractional Doppler shift at the instant the satellite is first visible from the beacon.

A satellite is in a 400-Km high circular orbit.
Determine:
a) The orbital angular velocity in radians per second.
b) The orbital period in minutes.
c) The orbital linear velocity in meters per second.
d) There is a very important satellite orbiting the earth doing astronomical research with a similar orbit. Which one is it?
f) Why it uses such a low orbit?

## Homework Equations

maybe V = squareroot u/R.

## The Attempt at a Solution

I'm using f = ( v/v+vs) fo.

## The Attempt at a Solution

Filip Larsen
Gold Member
Try make a diagram of the situation that includes the position of the centre of earth, the observer and the satellite. Take note of which geometric distances and angles you know about. Then think about which direction of relative motion of the satellite relative to the observer that contributes to Doppler shift and see if you can relate that to the sketch you made.

The above hint is based on the assumption that you are supposed to utilize the special geometry that are present in the situation specified by the problem text. To calculate the Doppler shift for general satellite orbits and positions you would need some more complicated equations.

TQ for the solutions.

Anything for the next question?

Filip Larsen
Gold Member
Please explain which question you are stuck on and what you have tried already.