The LightSquared Kerfuffle

We had a great discussion about the ugly problem of GPS interference last week and why it can’t be oversimplified.  Yesterday, venture capitalist Philip Falcone – a major financial backer of wireless startup LightSquared – slammed the GPS coalition for opposing LightSquared’s plans to use satellite spectrum for terrestrial wireless broadband.  Falcone reiterated the same talking points used by LightSquared regarding GPS devices lacking the proper filtering, and GPS device misuse of spectrum that was allocated to LightSquared.  The problem, however, is that he didn’t address the fundamental issue of what we’re going to do about all those GPS devices that will experience interference.

First let us summarize the undisputed facts of this debate:

  • There are 500 million GPS receivers in this country.
  • GPS receivers lack adequate filtering systems because they weren’t required to have them.
  • LightSquared’s proposed terrestrial transmitters (if approved by the FCC) will interfere with those millions of GPS devices.  This includes GPS receivers used in aviation.
  • It will be extremely expensive to replace the existing GPS receivers, and no one is volunteering to write the check.
Conflicting assertions from some major players:
  • If LightSquared switched to using its lower frequencies, the company claims that “only” 200,000 GPS receivers will be affected.
  • The United States Global Positioning System Industry Council (USGIC) says: “There is no question, however, that many types of GPS receivers and GPS-dependent applications will suffer harmful interference from LightSquared’s operations in the lower channel, even when transmission power is limited to one-tenth the authorized limit that was used in the testing”.
  • Extensive testing has not been done on the newly proposed spectrum in the lower block.
  • Even if the 200,000 claim is true, no one is offering to write a check to pay for the replacement of those 200,000 receivers.
The engineer’s view on filters:
  • It’s not just the problem of replacing GPS receivers, it may not even be possible to build a good enough filter.
  • The problem with real-world radio filters is that they can only reduce noise.  When they do reduce the noise, they also reduce the passband signal which is needed by the GPS receiver.
  • I have asked many engineers if it is possible to build a filter that can filter out a neighboring signal that is a billion times stronger than the GPS signal and do it in a way that doesn’t make the GPS signal unusable.  The only response I have received from engineers is that such a filter is not possible.
  • Even if such a filter existed – and it was affordable – how would we address the problem of replacing the existing GPS receivers?
The reality, therefore, is not nearly as simple as Mr. Falcone would have us believe, and there will be GPS interference no matter what portion of the spectrum LightSquared uses.  Given this harsh reality, it’s unclear how anyone – even those sympathetic to the company – can support LightSquared’s plans.
  • Richard Bennett

    There are a number of issues here that aren’t immediately obvious to the casual observer, so it’s not really correct to take the position that LS is wrong and the GPS companies are right. There’s more than one GPS system, for example, and the major conflict is between LS and a particular flavor of GPS – HD GPS – that is currently operating outside the scope of its rights.

    If HD GPS has been using unauthorized spectrum and can’t live without it, then we have to look at what fees they should be paying for the privilege. It may turn out that the best resolution if to re-locate LS somewhere else, at the GPS industry’s expense, but that’s far from certain.

    In any case, the situation is far from black and white and we haven’t seen the last word on it yet.

    • Eric Gakstatter

      “There’s more than one GPS system, for example, and the major conflict is between LS and a particular flavor of GPS – HD GPS – that is currently operating outside the scope of its rights.”

      Please expand on this. I’d like to know which type of GPS system is “currently operating outside the scope of its right.”

    • Eric Gakstatter

      Ok, I guess you don’t know. Fair enough. I’ll help you out. LightSquared sells satellite communication services to the GPS industry in the MSS band. In their course of business, naturally they promote GPS device-makers to look into the MSS spectrum to use those services. It’s been that way for many, many years with LightSquared and its predecessors (Skyterra et al). If LightSquared chooses to exit that business, that’s fine, but don’t blame it on the GPS device-makers and try to claim that GPS devices are “operating outside the scope of its rights.” That would be sort of like a building owner calling the police on a restaurant tenant claiming they are trespassing while still collecting rent from the restaurant.

      I agree, this debate is far from over. However, what’s going to gravely hurt LightSquared and the FCC at the end of the day is lack of sufficient notification. The case can’t be made that the GPS user community (all markets including aviation, engineering, GIS, machine control, etc.) knew about this any earlier than late last year. Sorry, the US GPS Industry Council doesn’t speak for the GPS user community. It never has.

      The precedence has already been set on how to approach action that would render a massive amount of GPS receivers obsolete. Back in 2008, the U.S. Air Force proposed to discontinue supporting the semicodeless technique that is used by virtually every civilian L1/L2 high-precision GPS receiver in existence. It was the first time in history that an action would render several hundred thousand high-precision GPS receivers obsolete, a scale which is very similar to the impact of the LightSquared system.

      There was no industry coalition formed to engage the Air Force. There was no industry outcry. A public/private technical working group was not formed to test the effects on receivers if semicodeless was not supported. Why is that?

      The answer is very simple. The U.S. Air Force, to its credit, did a fantastic job of communicating directly with the GPS user community along with the Department of Commerce. It issued public statements describing the impact the action would have on high-precision GPS receivers.

      The U.S. Air Force did its homework. At the end of the day, it set a sunset date of December 31, 2020, to discontinue supporting the semicodeless technique. It correctly determined that 12 years is about the amount of time that would allow a smooth transition with a manageable financial impact to the high-precision GPS user community.

      Imagine if the U.S. Air Force had set a period of one year to transition away from using the semicodeless technique. That action would have destroyed the high-precision GPS user community resulting in billions of dollars in losses and widespread small business closure. Fortunately, they did their homework, understood the impact, and made the correct decision.

      LightSquared, on the other hand, either didn’t do its homework or intentionally kept quiet in order to fly under the radar and push its initiative through before the GPS user community (and others) knew what was happening. In either case, the GPS user community shouldn’t be held accountable in paying for the FCC’s and LightSquared’s lack of communication/notification.

      George is right. The GPS device makers can work towards trying to find a solution to co-exist (it doesn’t exist today), but there is no solution for the $2+ billion worth of receivers in use today owned/operated by tens of thousands of small businesses and Fed/State/Local gov’t agencies. Take a look at the FCC comment filings on this issue and you’ll see what I’m talking about.

  • George Ou

    Richard those are some excellent points. Let me be clear that I wasn’t taking sides. I was only saying that there will be interferes with gps devices and that we can just go ahead and interfere with them. Consumers already bought those devices and they’re not at fault. It’s gps makers went well outside of their boundaries, then they should certainly pay to fix that problem. Moving lightsquared seems to be the right solution.

  • George Ou

    I meant to say cannot just go ahead and interfere with those gps devices.

    Mobile device entry is tricky.

  • Steve Crowley

    LightSquared may have been looking to swap spectrum from the beginning. A convenient way to dump the satellite component.

Comments are closed.