Last week LightSquared sent a letter to the the FCC blaming the GPS industry for interference problems that could come from its proposed broadband towers. This week the GPS industry responded.
WASHINGTON - For months the general aviation industry has expressed their concerns about LightSqaured broadband plans causing interference with their GPS navigation systems. Now, the unmanned vehicle industry has voiced concerns that precision GPS systems in UAVs could also be severely affected by LightSquared’s broadband initiative. At the AUVIS 2011 Symposium, stakeholders had the opportunity to weigh in on LightSquared’s controversial plans to launch a nationwide broadband network.
A panel made up of Melissa Rudinger, of the Aircraft Owners and Pilots Association (AOPA); Ken Alexander, navigational team leader at the Federal Aviation Administration; Ann Swanson, an attorney representing Garmin; and Geoff Stern, vice president of spectrum development at LightSquared discussed pros and cons of LightSqaured’s plans to deploy 35,000 base stations in an effort to provide complete 4G broadband coverage to the entire United States.
Initial tests of the system show it would interfere with GPS signals. Stern says LightSquared has always been willing to compromise on a solution to the problem. In recent months aviation groups have called for LightSquared to stop their plans completely, but in today’s panel, all sides seem committed to seeing an outcome that would benefit all parties.
However continued finger-pointing on all sides shows that compromise is still a long way off.
Less than a week ago, LightSquared filed a letter with the FCC saying GPS manufacturers were to blame for unwanted interference for making devices that accepted frequencies outside of their licensed spectrum.
“Had the GPS industry complied with DoD’s recommended filtering standards for GPS receivers, there would be no issue with LightSquared’s operations in the lower portion of its downlink band,” LightSquared executive vice president for Regulatory Affairs & Public Policy, Jeffrey Carlisle said in the letter.
But Michael Ritter, president and CEO of NovAtel, a GPS manufacturer out of Canada, says that’s not how things happened.
In a comment during the question and answer session, Ritter said LightSquared should “tell the truth” about why GPS manufacturers designed devices to pick up frequencies in that part of the spectrum, and accept responsibility for being part of the problem. LightSquared is no stranger to the GPS industry. In fact, it’s where they got their start, he said.
LightSquared originally started as a satellite communications company and is a leading developer and supplier of mobile satellite communications services. GPS companies actually use LightSquared satellites to provide their services. In addition to the area on the radio spectrum in question, the company also holds several others.
Ritter explained that when some companies began services with LightSquared, they were told their devices had to pick up bands in LightSquared’s other frequencies to be flexible for possible changes. In doing so, these companies deliberately developed their GPS systems to pick up the frequencies in the band being disputed right now.
"Signals that GPS receivers listen to in the MSS bands are the differential corrections that are used to make the GPS more accurate. These are provided by Omnistar and Starfire utilizing the Inmarsat and Lightsquared satellites. Both contracts state that the GPS receiver has to listen to that entire band," according to Ritter.
Stern says LightSquared never told any customers how they had to make their devices to use its service.
Ritter said that he was concerned about the effect LightSquared’s transmitters could have on high precision GPS systems in UAVs. In tests earlier this year, it was determined that even if LightSquared broadcasted at lower than intended frequencies, it could cause GPS malfunctions. Ritter said the impact would affect both UAVs and ground-based unmanned vehicles.
In filings, and repeated at the panel, LightSquared said it would be willing to work with the GPS and the aviation industries on creating a filter that could be added to existing GPS devices. But this filter, that “has yet to be invented or manufactured won’t work…and even if it did work, it would take a decade or more to implement it,” Rudinger said.
Ritter disagreed slightly. He said one did exist -- it’s just not practical for the UAV industry.
“The filter, it’s the size of a shoe box,” he told Security Management after the discussion. In UAVs, the gps board is "this big," he said holding his fingers roughly an inch apart, "compare that to the shoebox size filter." While more missions are being added to an already long list of duties for small UAVs, the last thing engineers are looking to do is add more weight.
In her opening statement, Rudinger said the FCC should share the blame too.
“The FCC holds some responsibility for allowing this issue to get this far along in the first place…It’s unfair to rural communities who need that 4G service…It’s unfair to the aviators…And it’s unfair to the business person who wants to be successful,” she said.
The FCC is supposed to help to "mitigate these issues early on and come out with a solution that works for everybody,” she added.
photo by smith from flickr