General Concept
All Orbitracs OPM mounts are conc
eived as counter balanced two axis motorized polar mounts.
Polar Mount signifies that the « horizontal » antenna motion is made around an axis parallel to the Earth’s axis of rotation; a principle widely applied in astronomy for many centuries. It makes that repointing between different satellite positions is performed by acting on a single actuator. And tracking of an inclined satellite is achieved with a second actuator in a perpendicular plane, as illustrated in the figure.
The Counter Weight compensation (up to now mainly applied for extreme large antenna systems), makes that the system is inherently stable and the load on the motors very low. This improves accuracy and lifetime and reduces power consumption.
A third major feature realized in all Orbitracs OPM systems is the fact that tracking of inclined orbit satellites is achieved by means of mathematical modeling of the satellite motion.
This unique feature cannot be found in any other Earth Station product. Basically the System Controller holds mathematical models of all inclined satellites accessible in the field of view. And when re-pointing the station to an inclined satellite, the corresponding orbit model is automatically loaded and tracking will start immediately. Thus all satellites, stable and inclined can be accessed in a fully transparent manner.
An important consequence of the polar mount principle is that the re-pointing movement is performed in a plane parallel to the equatorial plane. This means that the polarization angle with respect to the orbit arc is constant. Consequently there is no need for polarization adjustment when changing satellite and full functionality is obtained with only two motorized axis. There is no need for feed rotation motorization.
