
How The FCC Plans To Destroy GPS – A Simple Explanation - bwsd
http://freegeographytools.com/2011/how-the-fcc-plans-to-destroy-gps-a-simple-explanation
======
Kadin
Ugh, c'mon, people. The FCC isn't planning to destroy GPS. I hate the FCC as
much as the next guy on the Internet, but that's too ridiculous for
consideration.

What they're trying to do is balance the legitimate right that one user has to
a piece of spectrum, with the legitimate right that a lot of users have to
some that's adjacent. They'd be looking at nothing but an endless series of
lawsuits if they told LightSquared that they couldn't use their spectrum
(which they have a license to), particularly since LightSquared has a proposal
which -- yes, on paper, but what's on paper matters -- says they'll not
interfere with GPS.

It looks much more like the FCC is giving LightSquared an opportunity, either
to show that they can make the system workable, or to come up with enough rope
to hang themselves, one way or the other. If LightSquared can't resolve the
interference issues, then the FCC will have a much better case for an
enforcement action than they currently do. (Although an enforcement action
might require a rule change, because it's not clear that they would actually
be in violation of the rules; front-end overload is typically the receiver's
problem, not the transmitter's.)

I'm all for spectrum users being vigilant, and perhaps GPS users need an
organization analogous to the ARRL (which protects the Amateur Radio spectrum,
and successfully defeated the shitty BPL implementations that were kicking
around a few years ago) to nip these things in the bud. But the conspiracy-
theorizing is a bit rich.

~~~
oigftrgtyh
Has the FCC ever bothered to actually go after people that abuse bits of the
spectrum? Wardrobe malfunctions they are right on top of - but anything that
requires technical knowledge seems to escape them.

GPS does have a group that protects it's users - I believe it's called the
USAF.

~~~
kpeel
Funny enough, if GPS does get jammed, the USAF has a whole lot of equipment
that would be almost useless... Like every modern airplane they own.

~~~
mkr-hn
We need someone with air force experience in here. It doesn't seem like they'd
let them fly without knowing alternate ways of navigating.

~~~
kpeel
Yeah, I was joking a little. Most aircraft would still work pretty well off of
inertial data. However there are quite a few weapons systems that just plain
won't work without GPS.

BTW, I'm not a pilot, but I work for a government aerospace contractor, so I
have some experience in this.

~~~
icegreentea
I thought the most common ones (JDAMs) still had an inertial navigation system
cause GPS/INS is used nearly everywhere. It'll probably have horrible accuracy
(I guess that depends on how the coordinates sent to the bomb are handled...
if it can be calculated as an offset of what the INS thinks it is, then it
wouldn't be that bad). But still better then unguided bombs.

------
rit
While an interesting article which does a good job of breaking down the
technical details AND citing industry, it doesn't seem to me the FCC is
"Planning to destroy GPS".

This sounds a lot more like the FCC not entirely understanding the
ramifications of what they approved and/or a company trying to take advantage
of licensing loopholes which have unforeseen consequences.

Yes, the FCC fucked up here but it isn't time to bring out the tin foil hats
yet.

~~~
InclinedPlane
This isn't just a clerical error, this is the very reason the FCC exists at
all.

This would be like the FDA accidentally approving a new drug that gave
everyone in a 1 block radius cancer.

~~~
lukeschlather
Not at all. It's like the FDA approving a drug with a 100 mg /day dose, and a
company rolling out a plan for 200 mg /day dose, and trying to convince the
FDA that 200 mg is safe. Unless they actually get approval for 200 mg, they're
not going to be able to ship.

~~~
roc
And continuing the metaphor: having the FDA say "If your self-funded trials
say it's Ok, then we're satisfied".

The funny part is, some times, that's how the FDA _does_ work. That's how we
wound up with all those depression drugs that were only as effective as a
placebo.

------
crikli
I'm a licensed (technically "certificated") private pilot and this is article
is bullocks.

Aviation, both general and commercial, relies increasingly on GPS integrated
avionics to navigate the rigidly defined airspace that instrument rated pilots
refer to as "the system."

GPS has become so prevalent that the decades old method of navigation using
VOR (VHF omnidirectional frequency) radials is going the way of that which
came before it, ADF ("Automatic" Direction Finder).

Even the smelly old 1965 Piper Cherokee I fly sometimes has a Garmin GPS unit
in it. The guy that taught me to fly has a 1947 Cessna 140 with a GPS unit.
It's become ubiquitous in general aviation and is a de-facto requirement in
commercial aviation.

GPS isn't going anywhere because it's too crucial to one of the major facets
of the national transportation system.

~~~
marshray
Perhaps you can explain why the FCC is granting this license/waiver even in
the face of vehement opposition from a broad collection of GPS manufacturers
and aviation groups?

[http://licensing.fcc.gov/cgi-
bin/ws.exe/prod/ib/forms/report...](http://licensing.fcc.gov/cgi-
bin/ws.exe/prod/ib/forms/reports/related_filing.hts?f_key=-216679&f_number=SATMOD2010111800239)

~~~
crikli
The opposition was vehement, yes, but limited to strongly worded letters from
(mostly) small general aviation companies. No Boeings, no American Airlines,
no 'big guns' with be-suited lawyers to make the FCC wake up and smell the jet
fuel.

Wait until a couple airliners go missed on RNAV GPS approaches in low IFR
conditions (visibility < 1 mile or cloud ceilings at less than 500 feet). The
airlines will raise hell, the FAA will get involved and that'll be all she
wrote.

~~~
marshray
I think this company is a customer of Boeing's. Boeing builds their
satellites.

As for the airlines, they are so heavily regulated that they might think twice
about filing official comments on stuff like this without permission. No doubt
FAA and FCC are talking about this even if it's not official. Their offices
are only a few blocks away.

------
riordan
Meanwhile, the FCC's enforcement chief just put out a press release decrying
cell/GPS jammers saying they "create safety risks".

[http://www.fcc.gov/Daily_Releases/Daily_Business/2011/db0209...](http://www.fcc.gov/Daily_Releases/Daily_Business/2011/db0209/DOC-304575A1.pdf)

~~~
derleth
Well, they do: Doctors and other medical professionals have come to rely on
cell phones to be notified of emergencies quickly enough to save lives. If
they are blocked, there's a realistic chance lives will be lost for no good
reason.

(I've never heard of a good reason to block cell phone transmissions. It
always seems to come down to trying to enforce some vision of politeness via
technical means, which doesn't take considerate cell phone usage into account
at all.)

~~~
X-Istence
This is why it should be possible for theatres and the like to set up
alternate base stations that cell phones connect to, this way 911 calls and
text messages incoming may still be delivered but no incoming/outgoing calls
may be connected.

~~~
derleth
In the scenario I'm describing, the doctor is going to the theater when they
get a call from the hospital saying there's someone there who needs their
skill. (It's actually in their contract that, while they're on-call, they have
to remain within a certain amount of travel time from the hospital so they can
get there in time. This does affect home purchases.) If their cell phone is
blocked, the call is missed and someone may very well die.

You could (presumably) attempt to fix this with technology. It might even work
for a while, but when it breaks, someone could very easily die. And they'd
have died of someone else's dislike for cell phones, which is not a good
reason.

------
jcr
(sigh) The article was written by an alarmist moron trying to push his own
agenda, and most likely, pushing it for his own profit.

The only real problem is GPS equipment manufacturers intentionally cut corners
and costs by _FAILING_ to implement proper bandpass filters.

When the LightSquared towers get turned on, and customers who bought
incorrectly designed garbage from the likes of Garmin, the result will be
simple: The equipment makers will get sued in massive class action law suits
for selling broken equipment. And yes, the manufacturers deserved to be sued
for cutting corners on bandpass filters and selling junk since THEY HAVE
ALWAYS KNOWN the adjacent spectrum frequencies could be used at any time.

------
marshray
It's possible the LightSquared transmitters will be far more directional than
the Garmin test gives them credit for. They may not run full power all the
time anyway.

Regardless, it's generally the responsibility of the receiver to ignore
signals in another part of the same band, and this is a different band
entirely. Perhaps some receivers are built as cheaply as possible and don't
have the best filters. If they all break, well, their customers should know
not to trust that brand again. Any other policy amounts to no one ever being
able to establish new radio service on its own part of the spectrum, on the
theory that some other defective other equipment might fall over.

Personally, I think it's far more interesting the prospect of having a network
of 20,000 steerable-beam transmitters approved for 15KW ERP each at 1.5GHz.
300MW is about half the output of a typical electrical power plant. If those
were networked that could make one hell of an antisatellite weapon, phased-
array radar illuminator, or maybe even an SDI-type directed energy weapon.

If the military isn't behind this, well they should be. <conspiracy
theory>Maybe that's why the FCC is fast tracking it so much.</conspiracy
theory>

~~~
jbri
It's the responsibility of the receiver to ignore signals transmitted at
appropriate power levels, yes.

The receiver is not required to be overengineered to cope with transmissions
vastly more powerful than expected - _that's why limits on broadcast power
exist in the first place_.

~~~
marshray
OK I see it now. It looks like everything in that adjacent band had previously
been designated space-to-earth.

I suppose it would be reasonable for an engineer to assume a receiver is not
going to end up within a few KM of a 15 KW transmitter at those frequencies.

~~~
X-Istence
At high power you can overpower adjacent frequencies wether you have good band
filtering on it or not. For example a 2 Watt FM transmitter at 100 Mhz can
easily overpower radio's tuned to 95 Mhz just because of its power, even with
the appropriate filtering.

~~~
marshray
The internationally-agreed upon plan for the adjacent band was to have all the
transmitters in orbit and all the receivers on the ground. So I don't think a
2W transmitter in orbit is going to overpower receivers in a different band.

40,000 of 15KW transmitters on the ground may be another matter.

------
machrider
Doesn't the military still rely heavily on GPS? I have a hard time believing
they'd tolerate any kind of interference with such a crucial system.

~~~
oigftrgtyh
Yes - without it's operation many senior members of staff would be forced to
learn map reading to find their way around Washington (or at least their
drivers would)

------
iwwr
Google cache link:
[http://webcache.googleusercontent.com/search?q=cache:I2iCQGc...](http://webcache.googleusercontent.com/search?q=cache:I2iCQGcQ3YUJ:freegeographytools.com/2011/how-
the-fcc-plans-to-destroy-gps-a-simple-
explanation+http://freegeographytools.com/2011/how-the-fcc-plans-to-destroy-
gps-a-simple-explanation)

------
mih
Would this affect the upcoming Galileo platform too? Does it use similar
frequencies?

~~~
oigftrgtyh
Yes if you could actually get Galileo receivers !

Galileo changed the frequency to be slightly different to GPS to allow
selectively blocking one or the other - but it's still close enough for this
to interfere.

------
Dramatize
That site looks pretty spammy. You sure this isn't just an attempt to build
links?

------
wickedchicken
I thought GPS was spread spectrum which would make it resistant to these kinds
of interference? After all, GPS satellites broadcast at the same frequency _as
each other,_ that's the genius of how GPS works.

~~~
X-Istence
By the time the GPS signal reaches earth it is at a very low power, think
milliwatts.

Lets think of it as you trying to eavesdrop on a meeting.

You have your ear pressed on a big thick wooden door that lets very little
sound through, you are attempting to hear so you have everything around you
very quiet and try your best to hear that very faint sound of your boss
talking about the companies plan to fire everyone. Now your co-worker just a
cubicle down is on the phone and instead of keeping it down is talking very
loudly. It doesn't matter how hard you try to listen for the sound from inside
the meeting all you can hear is your co-worker.

Now think of your boss in the meeting as the GPS satellites and your co-worker
as this new company.

Unfortunately when it comes to transmitting power, the more you have of it the
more likely you are to overpower other signals. This is the same issue that FM
transmitters have as mentioned in the article.

Unless we put better band filters on GPS devices and attempt to filter out a
very high power signal GPS is going to get lost in the signal that is being
transmitted from the ground.

~~~
derobert
GPS signal strength at Earth's surface is -130dBmW, so that'd be attowatts...
A GPS satellite capable of 0dBmW would be truly scary; it'd have about a
petawatt of electrical supply.

See, e.g., <http://gpsinformation.net/main/gpspower.htm>

------
fuzzmeister
Has the FAA said anything about this? I would hope that they would be
concerned about the impact on aviation GPS.

------
jrockway
I'm looking forward to a VOR/DME receiver in my phone to make up for the loss
of GPS.

