As you might expect, acquiring a signal from a satellite traveling at speeds of over 28,000 km/h (17,400 mph) can be a tricky business. A new system called SARAS, which is a Spanish acronym for "Fast Acquisition of Satellites and Launchers," more than doubles the effective area of the receiving dish antenna, allowing the signal to be acquired much faster.

When a satellite begins transmitting signals after separating from its rocket, the receiving station on the ground needs to be pointing at precisely the right spot to catch the highly focused and narrow beam transmitted by the fast-moving satellite.

"If the antenna is not pointed perfectly, or if the satellite zips by out of its 'field of view' before acquisition, the signal could be missed altogether," says Magdalena Martinez de Mendijur, a systems engineer at ESA’s Operations Centre in Germany. "Traditionally, even the best stations – like ESA’s 15 m (49 ft) and 35 m (115 ft)-diameter dishes – are only sensitive across an arc of just a few degrees."

The new SARAS system, which was developed by Spanish company Isdefe with support from the ESA's General Support Technology Program, sees eight small radio-frequency sensors mounted in a circular array around the rim of an existing dish antenna.

"The signals received by these eight are combined, and the system can estimate the direction of arrival of the incoming radio beam, and the entire dish can be repointed directly at the satellite with great precision and accuracy, even when the incoming signal is weak or distorted," says Magdalena.

Klaus Juergen Schulz, who is responsible for ground station engineering, adds that the system more than doubles the size of the dish's window and can acquire a signal from a new satellite in less than 12 seconds, with a future version expected to improve this to just two seconds.

The SARAS system was fitted to the 15 m dish at ESA's Space Astronomy Center in Spain last year and in testing has caught signals from various missions, including CryoSat-2, XMM, GOCE and SWARM.

The plan is to develop the system into a full commercial product. It has already been patented in Spain and is currently being patented in Europe.

The following video shows the SARAS system being installed and in operation.

Source: ESA

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    Darren Quick

    Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag.

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    • I'm very interested in tracking tech..

      I also may be a bit slow...

      What is the new feature here?? What is the patentable invention?? (Or is it a design patent they are seeking rather than an innovation patent)

      I am genuinely curious.

      What is new about using multiple antennae, positioned outside the focal zone of a directional antenna system, to estimate the location of a radio transmitter. (it is basically just a compound wide and narrow FOV tracking system such as is used by many radio detection systems.)

      How is this better than using off axis antennae adjacent to the primary?

      Of course management always loves the ability to produce a new "patentable Idea" (everyone in design thinks up several every day).

      Of course if it is the exact configuration and brand/type of actual antennae (radio frequency sensors) then it can be covered by a design patent (just as a new design for a toothbrush or spoon is allowed to be patented under the design category).

      Distinction needs to be made between innovation patents (which protect valid inventions and it protects the idea from being commercially used by competitors for "some years") and design patents (which stops people making exact replicas commercially).

      Just asking.

    • @ MD At the very least putting the seeking antennas on the dish eliminate the parallax and steering problems of using separately mounted antennas.

    • There have been phased array antenna since the 1950's -- started in the vacuum tube era! It seems addled to me that we are still physically turning dishes in 2014.

      What these Spaniards have done is make a very weak, timid phased array with only the purpose of pointing the dish. Patentable? I doubt it!

      By the way, the big radio telescopes need to be dishes because of the need to super-cool the receiver. It's different when you are seeking picowatts.

    • @ piperTom Dishes not only amplify the signal they are also very directional keeping other noises out making them very hard to jam. Also the footprint of a phased array antenna is absurd.


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