# How to calculate azimuth and elevation angles from satellite point of view of a ground station?

How to find azimuth and elevation from satellite of a ground station when yaw, pitch, roll, lat, long position of satellite and lat, long position on ground are given?

aflong = 10.3082;% Earth Station Longitude (degrees)
aflat = -6.0636; % Earth Station Latitude (degrees)
lslong = 0;      % Satellite Longitude (degrees)
lslat = 0;       % Satellite Latitude (degrees)
lspol = 0;       % Satellite Polarization (degrees)
alt = 700;       % Satellite altitude (Km)
yaw = 0;         % yaw(degrees)
pitch = 54.7356; % pitch(degrees)
roll = 0;        % roll(degrees)

• Seems like you would need to know the satellite's altitude as well. Oct 12, 2018 at 12:01
• I almost posted an answer based only on deviations from the nadir line, but it didn't use pitch, roll, and yaw. Can you explain how your "altitude-azimuth" coordinate system uses satellite attitude, if it does?
– uhoh
Oct 13, 2018 at 2:10
– uhoh
Oct 13, 2018 at 9:27
• @kartheek The pitch/roll and yaw are the attitude of the satellite with respect to something, e.g. the flight path. If you know where that is facing then its easier to say whether one should look left or right to find the ground station. Thereafter you need to know where the Antenna is located, or more specifically how its Alt/Azimuth relates to the pitch/roll/yaw body axes. Oct 13, 2018 at 10:06
• As others have said, you need to define what you mean by Az/El in this context. I'm guessing you are referencing Az/El to the spacecraft's body. In that case you need to transform the pointing vector (from the s/c to the g/s) to the spacecraft's body coordinate frame via a rotation matrix based on Yaw/Roll/Pitch. Once you have the pointing vector in the body reference frame, you can convert it to an Az/El (based on that same body reference frame) Oct 15, 2018 at 21:23