This motorised feed assembly and controller is iSat’s innovation project. Although still in development, we already have a working model and expect to release the product in the 1st Quarter of 2019.
It’s tracking performance will compete with currently available solutions but at a significantly lower cost.
Current tracking Methods
Step Track—This method of satellite tracking is based around constantly adjusting the antenna position to find the best receive level of a signal downlinked from the satellite. The problem with this method is that tracking movements are initiated by a drop in signal level. This means that the antenna is always following the satellite movements, not moving in unison. This results in fluctuations in received signal power at each end of the link and is also susceptible to interference which can cause loss of the tracked satellite completely. This method requires a motorised antenna as well as a beacon receiver and antenna controller.
Monopulse Tracking – This method is significantly more accurate than the others. A reference signal from the satellite is received by two separate elements within the antenna feed simultaneously and a comparison of the signal at the 2 different reception points accurately predicts the location of the satellite. This results in much better tracking accuracy than can be achieved with Step-Track, but required more complex equipment and therefore greater expense. This method required a motorised antenna, a complex control system and a specialist feed. Because of the complexity and expense, this method is usually only implemented in large hub antenna’s.
External positional data tracking—More recently, a new tracking solution has emerged which uses very accurate positional data gathered by agencies which track celestial objects and make the data available online. An antenna can then track the required satellite by knowing exactly where it is and exactly where it will be at a given time. This eliminates two of the big drawbacks of beacon tracking (poor signal stability and susceptibility to interference/fading) although current solutions are still fairly expensive. This method requires a motorised antenna, and a tracking controller
Our method is an evolution of the external positional data tracking method in which the antenna reflector is fixed and instead the feed moves along a single axis of travel in order to steer the antenna beams in unison with the satellite. Add in some positional data and some clever maths and we now have a tracking solution which is far more accurate and reliable than Step-Track and significantly cheaper than any other commercially available solution. Not to mention it can be retro-fitted to an existing fixed antenna so you can go inclined with minimum effort and minimum cost. This method requires a fixed axis antenna and our inclined orbit tracking system.