(April 2011) BY NOW I HOPE YOU’VE heard of the plan by a company called LightSquared to install as many as 40,000 stations across the continental United States that would transmit on the frequency band directly adjacent to the one used by GPS. LightSquared’s plan is to create, using this quiet little corner of the spectrum, a powerful, largely ground-based mobile broadband network that would allow users on the ground to surf the Web at high speed across the United States.
To put it lightly, there are huge problems with this plan. According to tests conducted by Garmin and Trimble and presented to the Federal Communications Commission (FCC), the proposed network would interfere disastrously with GPS receivers. Garmin reported that a single LightSquared transmitter would cause a Garmin GNS 430W, the most popular GPS receiver in general aviation, to detect interference at around 13 miles, lose a great deal of its signal at approximately seven miles and lose its position altogether at around five miles. It can take, the report continued, up to 90 seconds for the receiver to regain its bearings.
You don’t have to be a pilot to figure out that this is a very bad thing for safety. Imagine sticking 40,000 pushpins into a map of the United States, and you get the picture. These transmitters will be all over the place, and every one of them will be a black hole for GPS reception. The proposed network would surely be the death of sole-means GPS navigation and WAAS approaches, and perhaps of GPS navigation itself.
What makes this all the more troubling and baffling is that LightSquared’s primary collaborator has been none other than the FCC, the federal agency that is supposed to be in charge of safeguarding the spectrum, not booby-trapping it.
If the FCC had merely approved the scheme, that would have been bad enough. But what it actually did was unconscionable.
Many pilots know that the GPS signal we receive is a weak one, a fact that makes the worldwide satellite navigation system practical with a constellation of satellites as far as 23,000 miles away from Earth. So the FCC smartly limited the power of the satellites in adjacent bands so that the GPS signals wouldn’t be interfered with by more powerful signals on close-by frequencies. And LightSquared complies with that part of the plan. The satellites on which it will broadcast its 3G-like signal transmit a signal that, by the time it reaches Earth’s atmosphere, is very low power.
The part that would ruin GPS for everyone is LightSquared’s scheme to install “backup” transmitters on the ground to supplement its satellite system. In this “backup” plan, LightSquared is being duplicitous. These terrestrial transmitters aren’t backups at all. They are actually the backbone of its proposed service and business plan. Without them, LightSquared couldn’t offer true broadband mobile service. While helper ground stations are technically allowed, their inclusion in the system is clearly an attempt by the company to use its status as a satellite provider in order to establish a high-powered ground network that otherwise wouldn’t be allowed. It’s an extremely clever plan that would also do great harm. There’s a word for that: diabolical.
The worst part is that the FCC has signed off on the plan despite acknowledging the threat of interference. It has ordered a commission to study the effects, as if they weren’t already well understood, and it has ordered LightSquared to work with the GPS industry to figure out ways to help receivers properly filter the interference. Just how much that will cost GPS users — that’s you and that’s me — isn’t addressed, but adding filters and redoing hardware doubtless will cost thousands of dollars per unit.
While there are hundreds of thousands of aviation users of GPS, there are hundreds of millions of nonaviation GPS users who would be affected by LightSquared’s clever plan and the FCC’s negligent management.
If there’s any hope for the death of LightSquared’s dangerous system, it is that there is one user that matters more than the rest of us combined: the Department of Defense. It created GPS, allowed us to use it and counts on its accuracy for everything from smart bombs to battle planning. That the Defense Department hasn’t already nuked LightSquared’s plans is surprising. But I have little doubt that it will happen.
I admit that I’m probably not always the best advocate for light airplanes as business tools. I do have a good excuse, however. My lack of evangelic zeal on the subject is simply due to my deep-seated belief that small airplanes are perfect business tools. I know because I’ve been using them that way for most of the past 15 years. So if I forget to sing the praises of light airplanes as traveling machines, it’s only because I’m a true believer.
When it comes to traveling places in small airplanes, we often think of how they stack up against the airlines, and it’s a fair argument, to a point. (To make it a fair fight, you do need an instrument rating and you do need to stay proficient. That should go without saying.)