2.7 Ground Tracks

Question 1

Ground Track

Answer 1

Trace over earth of the area located directly below the orbiting satellite, determined by COEs and rotation of earth through the ECEF frame.

Question 2

Semi-major axis - ground track

Answer 2

Determines the orbital period.
The longer a, the smaller the ground track.
Geosynchronous orbit period is 24 hrs= no drift/i=0, e=0 is geostationary and looks like a dot on the ground track.

Question 3

Inclination - ground track

Answer 3

Highest altitude crossed by the ground track.

Retrograde orbit =over 90 moving west

Question 4

RAAN - ground track

Answer 4

Start of the ground track is the ascending node.

Different start point = different RAAN

Question 5

Eccentricity - ground track

Answer 5

Symmetrical ground tracks have zero eccentricity

Added shape means orbit has added eccentricity

Question 6

Argument of Perigee - ground track

Answer 6

a. Perigee is where the ground tracks expand over a larger amount of earth’s surface
b. Apogee is where the satellite is going slower and therefore covers a smaller amount of earth’s surface