Tag Archives: GPS Interference

LightSquared Interference Confirmed Again

In a statement released yesterday, the governmental group which reviewed LightSquared’s test results, the National Executive Committee for Space-Based Positioning, Navigation, and Timing (PNT), found that “Preliminary analysis of the test findings found no significant interference with cellular phones. However, the testing did show that LightSquared signals caused harmful interference to the majority of other tested general purpose GPS receivers. Separate analysis by the Federal Aviation Administration also found interference with a flight safety system designed to warn pilots of approaching terrain.”

The final analysis will be completed over the next several weeks, and PNT will issue a report to the FCC.

Additionally, the National Defense Authorization Act for Fiscal Year 2012 (HR1540 Sec. 911) passed through the House of Representatives last night, contains language restricting the FCC from granting final approval to LightSquared for its broadband system until the GPS issue is resolved. Rep. Mike Turner, an Ohio Republican who chairs the House Armed Services Subcommittee on Strategic Forces, proposed the language in the Act. It reads in part;

“(1) CONTINUATION OF CONDITIONS UNTIL INTERFERENCE ADDRESSED.—The Federal Communications Commission shall not lift the conditions imposed on commercial terrestrial operations in the Order and Authorization adopted on January 26, 2011 (DA 11–133), or otherwise permit such operations, until the Commission has resolved concerns of widespread harmful interference by such commercial terrestrial operations to covered GPS devices.”

In a statement issued by LightSquared CEO Sanjiv Ahuja he said, “We are pleased that the statement issued by the National Space-Based PNT Executive Committee, chaired by the Department of Defense and the Department of Transportation, validates LightSquared’s compatibility with the nation’s 300 million cellular phones. While we are eager to continue to work with the FAA on addressing the one remaining issue regarding terrain avoidance systems, we profoundly disagree with the conclusions drawn with respect to general navigation devices.”

He also said, “The testing further confirmed that the interference issues are not caused by LightSquared’s spectrum, but by GPS devices looking into spectrum that is licensed to LightSquared. We have taken extraordinary measures–and at extraordinary expense–to solve a problem that is not of our making. We continue to believe that LightSquared and GPS can co-exist.”

Given the fact that GPS existed long before LightSquared was issued the spectrum, and there are millions of existing receivers, it seems unlikely that the FCC, Congress and the Defense Department will take the same stance.

There will be another round of testing in January.


 

LightSquared's Own Test Proves Interference with Precision GPS Receivers

High-speed mobile broadband hopeful, LightSquared released a video yesterday that proves, in fact, that their equipment does interfere with high precision GPS receivers. In the video, LightSquared shows off a work-around alternate GPS antenna which does appear to filter out the interference.

The alternative antenna begs the question, however, who would pay to retro-fit the millions of existing receivers. Moreover, why should owners of existing GPS equipment be expected to retro-fit or replace their equipment in order to benefit a company that stands to make billions of dollars from using radio spectrum which was never intended for terrestrial use, and for which the company paid nothing?

As of this writing, full results of the independent testing by the National Telecommunications and Information Administration which were expected today, have yet to be released.

LightSquared and GPS Interference

Imagine you are at the controls of a small single engine airplane. You are flying in the clouds, relying on your instruments to keep you out of trouble. All you see out your windscreen is gray. You are setting up for an instrument (ILS) approach to a small airport. You are 1000 feet above the ground. To your right is a 2500 foot hill and to your left is a 1500 foot hill. Your glide-slope has you right on the mark. The displays on your instrument panel should have you popping out of the clouds at 500 feet above the ground, one and a half miles from the end of the runway, lined up on final approach.

Enter LightSquared. Imagine that while still in the clouds, lining up for final approach, your ILS receiver, which relies on GPS data from an on-board GPS receiver loses it’s signal or begins to report inaccurate information. Now where is that runway…and where are those hills?

Bloomberg reported on Friday, that leaked test results show LightSquared’s equipment, which is designed to provide terrestrial based wireless broadband mobile service, interferes with 75% of existing GPS equipment.

LightSquared has responded by claiming the leaked test results were incomplete in that the power levels used in the test are higher than those the company proposes to use. They stated further that using their proposed power levels, the system would only interfere with 10% of existing GPS equipment. Indignant, LightSquared has also called for an investigation into who leaked the results.

The complete test results are due to be released on Wednesday.

LightSquared came under fire earlier in the year, when, according to a story in the Daily Beast, Air Force General William Shelton told the House strategic forces subcommittee in closed session, “that the White House asked the general to alter his testimony to add two points: that the general supported the White House policy to add more broadband for commercial use; and that the Pentagon would try to resolve the questions around LightSquared with testing in just 90 days. Shelton chafed at the intervention, which seemed to soften the Pentagon’s position and might be viewed as helping the company as it tries to get the project launched, officials said.”

Majority investor in LightSquared, Philip Falcone has consistently given money to both democrats and republicans.

A series of e-mails and documents obtained by The Center for Public Integrity in September, document contacts from company officials and White House staffers concerning the company’s project, and requesting a meeting at an Obama fundraiser.