

Lightsquared network causing GPS interference. - briandear
http://venturebeat.com/2011/06/10/uh-oh-lightsquareds-network-is-screwing-with-gps/

======
bradleyland
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.

------
zargon
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>

~~~
Geee
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...](http://tmfassociates.com/blog/wp-
content/uploads/2011/04/GPS-filters.jpg)

------
ANH
Ouch. They've apparently launched a satellite:
[http://spacefellowship.com/news/art23835/proton-
successfully...](http://spacefellowship.com/news/art23835/proton-successfully-
launches-lightsquared-satellite.html)

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...](http://www.fiercewireless.com/story/two-government-agences-says-
lightsquareds-network-interferes-gps/2011-06-09))

------
foomcgoo
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.

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

~~~
madaxe
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.

~~~
dedward
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?

------
JonnieCache
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.

~~~
lutorm
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.

~~~
cal5k
The US military GPS operates on a different frequency than civilian GPS, so it
likely would not be affected.

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

~~~
cjoh
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>

