The attitude, or orientation in space, of a spacecraft, is
described by two coordinates - a latitude and longitude, relative
to the orbital plane. These are sometimes described as "alat" and "alon" or
"blat" and "blon" (the initial "b" is from the German "Bahn" or path). "North"
is perpendicular to the orbital plane, and "0 longitude" is toward perigee.
From the attitude, the position of the satellite, and the position of the
observer, the squint angle can be calculated - the angle between the
direct satellite-observer line, and the direction the satellite, and hence its
antennas, are pointing.