This question appears in Mumbai University > Satellite Communication and Network subject

Marks: 5 M

Year: May 2015

Orbital Parameters:-

Orbital parameters or elements (or Keplerian elements as they are technically called) are parameters required to uniquely identify a specific orbit. In celestial mechanics, these elements are generally considered in classical two-body systems, where a Kepler orbit is used (derived from Newton's laws of motion and Newton's law of universal gravitation).

Following are brief descriptions of such parameters –

• Apogee refers to the furthest distance that the satellite can have from the Earth. It can also refer to that point in the satellite's orbit at which the satellites reach the furthest distance
• Perigee refers to the closest distance that the satellite can have from the Earth. It can also refer to that point in the satellite's orbit at which the satellites reach the closest distance.

Orbital parameters

• Semi-major axis - The distance from the centre of the orbit ellipse to satellite's apogee or perigee point. This is also defined as the average distance of the satellite from the Earth's centre
• Semi-minor Axis - The shortest distance from the true centre of the orbit ellipse to the orbit path
• Focus Distance: The distance from the true centre of the orbit ellipse to the centre of the Earth
• Period - The time required for the satellite to orbit the Earth once
• Ascending Node - The precise point in a satellite's orbit that intersects the equatorial plane of the Earth as the satellite moves from the southern to the northern hemisphere (ascending)
• Descending Node - The precise point in a satellite's orbit that intersects the equatorial plane of the Earth as the satellite moves from the northern to the southern hemisphere (descending).