A miniature dual-band two-way mobile
satellite-tracking antenna
system mounted on a movable vehicle includes a miniature
parabolic reflector dish having an elliptical aperture with
major and minor elliptical axes aligned horizontally and vertically, respectively, to maximize azimuthal directionality and minimize elevational directionality to an extent corresponding to expected
pitch excursions of the movable ground vehicle. A feed-horn has a back end and an open front end facing the reflector dish and has vertical side walls opening out from the back end to the front end at a lesser horn angle and horizontal top and bottom walls opening out from the back end to the front end at a greater horn angle. An
RF circuit couples two different
signal bands between the feed-horn and the user. An antenna attitude controller maintains an antenna
azimuth direction relative to the
satellite by rotating it in
azimuth in response to sensed
yaw motions of the movable ground vehicle so as to compensate for the
yaw motions to within a
pointing error angle. The controller sinusoidally dithers the antenna through a small
azimuth dither angle greater than the
pointing error angle while sensing a
signal from the
satellite received at the reflector dish, and deduces the pointing angle error from
dither-induced fluctuations in the received
signal.