There’s been quite a debate raging recently between two powerful interest groups. No, I’m not talking about the budget; I’m talking about GPS. A company called LightSquared is about to roll out a nationwide wireless Internet system, apparently in partnership with Sprint. This sounds great… except that the frequency band LightSquared is planning on using overlaps part of the spectrum allocated for GPS use. In practice, that means that LightSquared transmitters work as fairly effective GPS jammers.
There’s no question about whether LightSpeed’s equipment interferes with GPS– it does, as their own tests prove. Their attitude is that the interference is partly due to the GPS industry’s failure to provide adequate filtering, although they don’t explain how the cost of this filtering would be borne, nor how it would work with the highly sensitive GPS receivers used in commercial and general aviation aircraft.
GPS is so widely used that any interference with it would have a huge impact on the people and companies that depend on it. Check out the member list of the “Coalition to Save Our GPS” and you’ll see what I mean: the aviation industry, farmers, surveyors, and city and county governments are all well-represented.
Here are my comments to the FCC. You can file your own if you’re so inclined:
When GPS was originally introduced, only visionaries thought it would be used beyond defense applications. Now it’s a critical part of our country’s economic fabric. It’s used to deliver precision timing, location, and navigation services to a huge range of users, including farmers, pilots, ambulance drivers, and telecommunications systems. Every day, GPS helps enable life-saving emergency services, efficient transport of goods and people, economical production of food, and hundreds of other vital activities.
Personally, my family and I depend on GPS signals to safely navigate the National Airspace System, both as passengers aboard commercial aircraft and while flying general aviation aircraft. We use it for navigation and location services when traveling. We depend on it in case of emergencies that require police, fire, or EMS response. In all of these cases, unavailability or degradation of GPS signals could potentially be quite dangerous, and even fatal.
LightSquared’s proposed frequency plan puts GPS at risk. For that reason I urge the FCC to deny their request to use the current proposed frequency range. GPS and LightSpeed’s current design are fundamentally incompatible. Although making high-speed wireless Internet service available over broad geographic areas is highly desirable, enabling the current GPS system to continue to work safely and reliably is even more reliable given how many industries and activities depend on it.