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FCC broadband improvements could disable GPS, say opponents

Apr 7, 2011 — by LinuxDevices Staff — from the LinuxDevices Archive — views

The Obama Administration's well-intentioned drive to quickly approve wireless broadband in rural areas could end up killing most GPS use in the United States, according to this eWEEK opinion piece. Opposition is said to be growing to the FCC's approval of broadband spectrum directly adjacent to GPS, which could cause disruptions from “receiver desensitization.”

It's no secret that the Obama Administration and the Federal Communications Commission (FCC) have been working hard to find ways to deploy wireless broadband Internet, especially to underserved areas. In general, this is an important move, since the current crop of broadband providers has shown little interest in bringing the Internet to rural and economically challenged areas.

Because of this, the FCC's Broadband Plan has resulted in a number of changes in how radio spectrum is allocated in the United States Now, however, in its eagerness to allocate new frequencies regardless of the impact, the FCC has approved a powerful new broadband system that uses frequencies immediately adjacent to the existing GPS frequencies.

LightSquared, the company that has been granted the use of these frequencies, has promised it won't interfere with GPS, and the FCC has said that it won't allow such interference. But the GPS industry isn't buying it, and neither are a lot of other groups.

The Department of Defense and Department of Transportation, which are jointly responsible for the GPS system, have already written to the FCC objecting to this frequency allocation. However, some believe that the FCC has ignored these concerns. Objections have also come from a wide number of industry and user organizations, ranging from the Aircraft Owners and Pilots Association to aerospace giant Lockheed Martin.

Why no testing?

What opponents are objecting to is that the FCC gave approval to LightSquared without doing any testing. After it received approval, LightSquared began installing base stations, and it has already started placing satellites in orbit. By the time testing takes place — starting in this month– the company will have spent millions on infrastructure with the approval of the FCC.

What has everyone so upset is that LightSquared, having spent the money to get its system running, is unlikely to willingly shut things down even if later tests find that the interference with the GPS system is significant. Company officials will likely argue that they have a right to operate regardless of any interference.

LightSquared will likely also get a favorable hearing from the FCC, given that its chairman, Julius Genachowski is a close friend and campaign supporter of President Obama, and is a partner with him in the drive to provide wireless broadband as quickly as possible.

Receiver desensitization a "very real" threat

Of course, many will point out that the LightSquared data solution doesn't actually use the same frequencies as GPS, and suggest that there's no problem. In reality, the problem is very real. GPS receivers, especially those in commercial applications, were never designed to reject interference from adjacent channels.

A strong transmitter on a nearby frequency will cause something called "receiver desensitization." This effectively keeps a receiver, especially a very sensitive receiver such as is found in GPS devices, from receiving radio signals.

I was able to create this condition by driving with a selection of portable GPS receivers to areas near radio and television transmitters. Most of them lost their GPS signals and were unable to navigate. Only the GPS receiver built into the car was able to maintain its ability to navigate. The broadcast transmitters overwhelmed the sensitive receivers in the GPS devices and rendered them useless.

While the broadcast transmitters were more powerful than the devices proposed by LightSquared, they were operating nowhere near the GPS frequencies. Transmitters operating on frequencies immediately adjacent in frequency will have a similar effect. LightSquared will field about 40,000 of those transmitters, and it's hard to see how they can avoid effectively eliminating GPS use in their vicinity for all but military and some commercial aviation GPS units designed specifically to reject interference.

Considering how integral GPS technology has become, it's difficult to see how the FCC can justify this approval, especially without having insisted on extensive testing first. But the FCC did just that, and clearly the agency seems to have not taken into consideration objections from the Defense and Transportation departments.

I don't think it will be any surprise that the FCC plans to move ahead in June after only the briefest of tests. Ultimately, this decision by the FCC could lead to chaos at best, and tragedy at worst. If the end result of the interference is problems with UPS deliveries and traffic jams, there will be chaos. If the interference keeps first responders from responding to emergencies or keeps airliners from navigating safely, there could be loss of life.

Either way, GPS has become so embedded in everything from cars and cell phones to M2M communications and modern farming techniques that the economic chaos could be massive. Unfortunately, the FCC is showing little indication that it's interested in delaying things for more extensive testing. There are solutions, such as getting Congress involved, which could happen considering the widespread opposition and the potential for economic problems.

But the choice by the FCC to approve a potentially harmful technology without testing it first seems like it's ultimately a lose-lose situation. GPS users will lose, and then ultimately so will the investors in LightSquared when at least part of the system is ordered shut down when the interference asserts itself.

Wayne Rash is a regular contributor to eWEEK.

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