Tuesday, June 14, 2011

Wireless Broadband Threat on GPS Confirmed

Since we first introduced the topic of LightSquared and their controversial encroachment on the GPS spectrum, it seems that the coalition to save GPS, the U.S. government, several private companies like John Deere, and even LightSquared themselves have been very busy testing the real impact of their technology on GPS. The prognosis: it's a mortal blow.

Two government agencies, the National Space-Based PNT (Positioning Navigation and Timing) National Executive Committee and the Federal Aviation Administration, tested LightSquared's technology. In May, they confirmed that the interference was significant.

Deere & Company, makers of John Deere agriculture equipment, independently tested their GPS units and confirmed that LightSquared's broadband transmitters create a dead-zone for their equipment up to a 22-mile radius.

First, how does this happen? Well, simply put, LightSquared is transmitting from earth's surface whereas GPS transmits from space. The intensity of the signal is overwhelmingly larger (40,000 times, to be exact). And, while LightSquared is not using the same spectrum that GPS uses (the FCC sees to it that doesn't occur) their spectrum is adjacent to the GPS spectrum. So, while devices used for GPS were tuned to listen very carefully to a weak signal, their magnifying technology also leaves them susceptible to interference when such a strong signal exists just a few wave-lengths away.

Second, however, is the question: what do we do about it? LightSquared has agreed not to deploy their network until a solution can be found. Awfully gracious of them considering it's not really their problem to begin with. And, mind you, they haven't asserted that they themselves must find (and fund) that solution. To date, filters and amplifiers have been suggested, but LightSquared has not (nor should not, in my opinion) bear the financial burden of deploying that fix. Their goal is to determine that a viable solution to the technological hurdle exists, however theoretical, at which point they can move forward with their plans knowing that their peers in the GPS industry have a recourse.

What's really at stake? Rest assured, plains will not fall from the sky and tractors will not go on an unguided rampage through neighborhoods--although that's more or less what the GPS industry would have you to believe. The risks are far more subtle than that. If/when LightSquared is able to demonstrate that a viable filtering option is available, there will be great costs to deploying. This could mean huge burdens for local municipalities and emergency response already working on tight budgets. Private farmers, agricutlural industries, and utility companies will have some costly upgrades to swallow in order to keep their GPS equipment in working order. All of this will mean either a higher tax burden or a higher cost of food and goods that depend on GPS, or both. Meanwhile, LightBound's continued mission is to deliver rural broadband in the interest of -- you guessed it -- economic development.

Is it all worth it? You tell me.

Labels: Fixed Wireless Broadband, GPS, Rural Broadband, spectrum