In an effort to reduce the amount of interference satellites face, the Satellite Users Interference Re-duction Group (SIURG) is working on a protocol to help identify the owners of interfering equipment.

Interference rarely gets headlines as it is a somewhat common occurrence but rarely lasts for an extended period of time. However, the recent hijacking of the AsiaSat 3S satellite to broadcast a pirate signal into Beijing for four prime time hours on Nov. 20 put interference back in the headlines.

“Prevention of deliberate of piracy of satellite capacity is difficult,” R. James Budden, vice president of operations at New Skies Satellites NV and chairman of SUIRG told Satellite News. “The major issue for SUIRG is to provide methods [to allow the location] of where those pirates come from very quickly. You need to have a system in place whereby you can locate that transmitter or identify that transmitter very quickly.”

To that end, the group is working with satellite manufacturers to get a protocol in place that would place a unique identifier on any transmission that goes to a satellite. That identifier would then be decoded at a monitoring station and would help speed up the process of locating where the interference signal is coming from or at the very least who is the owner of the equipment that is being used to interfere with the satellite signal. And once you figure out the individual who owns the antenna that is causing the interference, “it’s very easy to find [their location].”

However, it may take a while for the satellite industry to see the any protocol actually deployed in end-user equipment. “This is a fairly long term project” in terms of getting products with the identifier manufactured into them deployed “because there is a lot of equipment out there that could not be retrofitted with anything like this,” Budden noted.

In the mean time the industry will fall back on its “second line of defense which is transmitter location systems. These systems can locate an antenna fairly quickly, in minutes in fact in some cases if they have the data on the spacecraft and an adjacent spacecraft available.”

But that second line of defense also illustrates the need for more comprehensive identification data. “The problem is that in places like, for example, Hong Kong, which is a very small area, if the antenna is within Hong Kong, [a transmitter location system] wouldn’t give you much to locate that antenna because the measurement ellipse that comes from using two different spacecraft to locate the antenna on the ground gives you an ellipse of 30 to 40 kilometers by 5 to 7 kilometers,” Budden said. “As you can imagine, you can pack an awful lot of antennas in that sort of area.”

Protocol Catching Interest

Budden said the concept of installing an identifier into the signal is not new. “This was tried about 20 years ago and there was great resistance from the public telephone companies then who were the big players,” Budden said. “We have revived this with manufactures of DVB-type equipment. These manufacturers have indicated that if we come up with a protocol, they are happy to put it into new equipment if it becomes a requirement by the operators.” Budden added, “All the big operators are pushing for an ID system.”

SUIRG also has started a dialogue with VSAT equipment manufacturers. “That initially didn’t go as well, but in the last two or three months, they have asked us to provide them with data on how much ground equipment problems are causing interference on the spacecraft,” Budden said. He noted that SUIRG is generating a public database that ultimately will be available on the organization’s Web site (http://www.suirg.org) tracking interference problems by region, type of interference and when interference is generated from the ground, whether its human error, equipment problems or other causes.

Budden estimates that the protocol “should be out on the street sometime in the summer of 2005.” Assuming the protocol is accepted by the industry, Budden estimated it would take about six to 12 months before it started appearing in DVB modulators and 24 to 36 months before it is incorporated into VSAT equipment.

“To put something on the VSAT equipment, you haven’t got the amount of digital overhead that you are free to play with on the wideband DVB platforms,” Budden said.

— Gregory Twachtman

(R. James Budden, New Skies Satellites, +31 70 306 4208)