Tech Tuesday

Fight to Protect GPS Continues

The battle over the GPS satellite system and potential interference enters a new phase this week.

The battle over the use of a radio frequency spectrum by one company that could blank out GPS satellite signals for everyone else is now entering the comment review period by the U.S. Federal Communications Commission. The comment period, which closed Monday, offered major groups the chance to weigh in on the challenge of this controversy.

Let me recap. Late in 2010 a company called LightSquared, which had been providing satellite communication over a frequency band granted by FCC in 2005, decided to go in a different direction. This was due, in part, to the infusion of capital by new investors who saw a different business opportunity. Essentially, the group decided that instead of simply providing satellite phone support they would build 40,000 towers around the country and use that frequency band to provide wireless broadband data services.

A range of companies from Best Buy to Sprint became interested in the service given the demand to bring broadband service to more areas. And the FCC, using data provided by LightSquared signed off on the idea. However, FCC missed one key point - the signal that would be used is very close to the same frequency used by the now ubiquitous GPS system relied on by a wide range of users from construction workers to farmers to soccer moms lost in traffic.

The widespread outcry of concern over this issue, and creation of the group by a coalition of concerned industry players had the FCC call for more study. And an independent technology working group - that included LightSquared - went to work. Results of that groups work was released in late June.

Before the GPS experts pooh-pooh this concern by saying simple filtering could solve the problem, you should know that the technology working group - or TWG for short - found some startling information. Jim Kirkland, vice president and general counsel, Trimble, a Save Our GPS member, notes that the 975-page TWG report, which included work by more than 100 engineers, came out June 30. Kirkland spoke as part of an industry briefing on the issues, the TWG report and the comment period held for Save Our GPS members. Farm Futures sat in on the conversation.

He adds that LightSquared issued its own independent interpretation of the challenges and its own solution. A solution - using a different part of the band at a lower power - that Save Our GPS has already said was untested. LightSquared has said this solution would solve most of the issues with GPS - but be aware the areas where there would still be issues would be the higher-end GPS systems used by farmers and pilots to do their jobs.

Perhaps the biggest surprise was the fact that while engineers estimated that the signal LightSquared would use could be as much as 1 billion times stronger than the current GPS signal (hence the interference concern), actual tests showed the interference to be 749 billion times stronger - and yes that’s billion with a ‘b’.

”There are filtering technologies available,” says Kirkland. “But no filter we could test would work for this situation.” He adds that LightSquared set up different test scenarios and found significant impacts for aviation, cellular service. defense and other applications. The report concluded that if used LightSquared’s signal would make GPS unavailable in wide areas even several miles from the base station.

Kirkland adds: “LightSquared is now saying that this new plan will not cause interference problems. They have no credibility left...they have not done their due diligence.”

This issue is now entering the comment review period, but members of Congress are highly concerned. The Department of Defense is filing its own report on the potential impacts on classified systems. LightSquared has been making comments about the quality of GPS receivers on the market and their “cheap” designs. An issue Kirkland took issue with during the Save Our GPS presentation. “These receivers are deployed by the DOD, FAA and they did not scrimp on the technology,” he notes. “GPS receivers can resist signals that are millions of times stronger...but not 100s of millions of times stronger.”

For farmers concerned about your investment in this technology and its ability to work in the future, a call to your friendly Congressman (they might relish a discussion about anything but the national debt) is well timed now. Your personal call to their office, an email sent through their website or a personal letter about your concerns of this technology and its deployment would be worthwhile. I know recently I made a similar call - and its rare. Yet in these times when interest groups of all stripes are clamoring for attention or working the system to get their tech approved; you have to be vocal about the issues.

You can find information to contact your Congressman at To contact your Senator go to They should know your thoughts on this issue and the more that chime in the merrier.

As Brian Raymond, director of technology and domestic policy, National Association of Manufacturers, notes: “If FCC can find spectrum for this service, we don’t have a problem with that. We have nothing against LightSquared, but we want to protect GPS.”

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