Lightsquared network causing GPS interference. | Hacker News Reader

Lightsquared network causing GPS interference.

venturebeat.com

26 pointsbriandear16 comments

When the news first hit that Lightsquared was going to operate on a piece of spectrum that interfered with GPS, they raised a calming hand and told us all, "Don't worry, we've got technology that will prevent any inteference." Here we are, months later, and the story is now, "However, those solutions would likely be expensive for both the company and GPS device makers and could take years to complete."

Doesn't exactly inspire confidence.

This was a known problem with their design and the FCC gave approval for them to go forward anyway. Maybe they could have saved LightSquared some money if the FCC asked them to fix the GPS issues before deploying. See http://news.ycombinator.com/item?id=2199188

Well, the problem is basically in the GPS receivers, which get interfered by out-of-band signals. There's really no reason for FCC to not approve Light^2. http://tmfassociates.com/blog/wp-content/uploads/2011/04/GPS...

Ouch. They've apparently launched a satellite: http://spacefellowship.com/news/art23835/proton-successfully...

I wonder if it's the uplink, downlink, or both that's causing the interference. Anecdotal and probably coincidental: I live not too far from LightSquared's headquarters and my phone's GPS has had difficulty getting a lock the past few weeks.

I hope they work this out, because I'd probably be an end user of theirs. No wired internet access is currently available at my location.

Edit: Looks like it's the uplink from the base stations (http://www.fiercewireless.com/story/two-government-agences-s...)

As someone who flies just recreationally, this is a huge deal. While losing your GPS in the car is a nuisance, losing it in the airplane can be dangerous. More and more airports have only GPS approaches published, which means that a pilot (or crew) can be flying in to land in minimal visibility conditions and in certain cases not be able to even seen the runway until 200 feet off the ground.

Loss of GPS signal in these cases is downright dangerous.

You're also never supposed to rely on GPS while flying (AFAIK). Has that changed?

What he means is that plenty of small airstrips have no ILS (http://en.wikipedia.org/wiki/Instrument_landing_system) and just publish GPS glideslopes... and if you're landing in zero visibility and you lose GPS tracking, landing is going to be dangerously hard.

Right - but GPS is never supposed to be relied upon for anything - it's secondary.

If there's no ILS and zero visibility - you should be landing somewhere else, no?

http://en.wikipedia.org/wiki/Localizer_Performance_with_Vert...

GPS is also replacing ground-based radar for traffic control in the US.

It's a good idea to have alternatives in your cockpit, but 99% of the time GPS is the easiest and most accurate option.

Guess who actually runs the GPS network? The US Air Force. Guess how much of a shit they give about civillian applications of it? Zero.

Back to the drawing board...

EDIT: I'd like to point out that this isn't really meant as a criticism. If I was in the air force's position I wouldn't give a shit either.

That seems like a non-sequitur. Based on the article, LightSquare isn't an application of GPS. It's a wireless broadband network that just (unfortunately) happens to f with GPS signals.

Huh? Do you mean USAF doesn't care if Lightsquared screws up the GPS reception for civilians? Or do you mean they don't care if Lightsquared gets screwed?

If the first, presumably it would also interfere with USAF uses of GPS. And I don't think they would be entirely free from pushback, especially from commercial aviation and the FAA.

I mean the second, that they and by extension the rest of the US establishment is simply not going to allow any civillian technology to interfere with GPS.

Realise that's not entirely clear in the original post...

The US military GPS operates on a different frequency than civilian GPS, so it likely would not be affected.

Here is some information from the US govt. on the situation: http://www.pnt.gov/interference/lightsquared/

The best part of this is when they say "Oh, we're setting up a working group to help resolve this problem" and follow it up with:

"Due to FACA, the work of the NPEF is limited to U.S. government personnel and contractors."

The problem is procurement:

http://infovegan.com/2010/11/02/how-vs-what

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