
Pentagon official: FCC decision on 5G threatens GPS, national security - anigbrowl
https://thehill.com/policy/defense/operations/496555-pentagon-official-fcc-decision-on-5g-threatens-gps-national
======
jrockway
I don't think there's enough detail here to decide whether or not to be mad.
The L band is huge, 1000MHz-2000MHz. GPS uses a few tiny slices of this band.
Cell phones, amateur radio, weather radar (though not precipitation-detection
radar), ADS-B, and a ton of other non-military things are in that band. Adding
5G may or may not have any negative effect on GPS. I doubt they are proposing
to run their 5G network on top of the GPS frequencies, after all, because
everyone knows that would break GPS (which already operate well below the
noise floor).

One time when we were working on testing Wifi interference, we tried to buy
every possible 2.4GHz device to see what they did to our routers. We found
these TV extenders (connect camera to one end, connect TV to the other) that
claimed to be 2.4GHz but didn't interfere at all. We looked more closely with
a spectrum analyzer and they were actually 1.3GHz and completely stepped all
over the GPS frequencies. Did the FCC stop Amazon from importing these things?
Nope. I guess my point is... the threat is real, but someone going out of
their way to request permission from the government (as is legally required)
is probably not going to cause many problems.

~~~
Rebelgecko
I'm not an RF person, but the way it was explained to me is that GNSS signals
are in the neighborhood of 1560mhz-1610mhz. With the advent of GPSIII, even
more of the important signals are getting pushed outwards towards the extremes
of that range. Ligado/Lightsquared initially wanted permission to basically
surround GPS (1526-1559mhz and 1610-1660mHz)

After lots of complaints, they amended their request to leave a buffer of
20mhz or so between their signals and GPS. However, Ligado wants to transmit
at ~10watts, and the GPS signal is in the neighborhood of a _femtowatt_ by the
time it hits a receiver. That can apparently still cause interference. For the
GPS chip in your phone it may not make a huge difference. However testing has
shown degraded performance in aviation GPS receivers more than a mile away
from a 10watt transmitter. For even higher precision receivers (think surveyor
equipment or maybe an autonomous tractor) the radius of the degradation
stretches more than 2 miles from the transmitter. Ligado wants to put their
transmitters ¼ of a mile apart.

Source for some of those numbers here, and an entertaining talk if you're ever
able to see it in person: [https://rntfnd.org/wp-content/uploads/Brad-at-UAG-
Users-Advi...](https://rntfnd.org/wp-content/uploads/Brad-at-UAG-Users-
Advisory-Group-Oct-2019.pdf)

~~~
andromeduck
Why can't we just greatly improve the signal strength at source by an order of
magnitude? Like I know the new satellites can use beam forming to increase
power for some large area for military use but it looks like even so total
power is about ~500W right now. What's stopping us from deploying 10KW sats?

~~~
joecool1029
> Like I know the new satellites can use beam forming to increase power for
> some large area for military use

No, what you think you 'know' is plain wrong. Usually when discussing
satellites, we're talking about a directional antenna that focuses a spot or
wide beam for broadcast. A spot beam allows you to target a particular region,
DirecTV uses spot beams to provide local broadcasts to general regions of the
US. The military uses M-code shit on GPS with a directional antenna for the
same sort of use case.

Beam forming is a different concept where you get creative with multiple
antennas broadcasting at once and exploit signal cancellation to improve the
data rate by shifting the phase between them. It does increase your received
signal but relies on the receiver transmitting information back to the
satellite (which is not going to happen for GPS, at least not the vast
majority of consumer equip). Beam forming discussed on HN just last month:
[https://news.ycombinator.com/item?id=22784132](https://news.ycombinator.com/item?id=22784132)

> What's stopping us from deploying 10KW sats?

Sat power is around and above that already, it doesn't make sense to increase
the spot transponder ERP too much or you end up with issues like interference
with adjacent bands since RF gets trickier to filter the higher the power it
gets. Keep in mind a comm satellite usually has lots of transponders using
maybe 100-500W each, so it adds up to some geosynchronous ones being like 20kW
total consumption. Smaller LEO ones obviously not going to be close to that.

GPS released a paper about interfering with itself:
[https://www.gps.gov/multimedia/presentations/2010/10/ICG/bet...](https://www.gps.gov/multimedia/presentations/2010/10/ICG/betz.pdf)

Communications history is littered with failure stories of people who wanted
to throw power at the problem, when they only needed to find ways to listen
better.

~~~
andromeduck
Thanks that's actually helpful. I did some more reading and it looks like it
is as you say, the new military transmitters are directional and steerable,
beam forming done on the receiving side.

But still it seems that power is still part of the solution given the
increased power density of the new military antennas. I guess what I'm
wondering is why they can't just reserve more band, move to regional antennas
for whatever other technologies in addition to fighting
polluters/jammers/spoofers and noisy neighbors. Or is that the plan?

------
thoraway1010
The history of lightsquared, the company involved, is horrendous. They bought
spectrum with a SPECIFIC restriction on it to avoid GPS interference - then
proceeded to get a proposal approved that violates that restriction. The
amount of bad faith dealing by this company was eye opening.

I thought Garmin / Trimble and basically every GPS company had sued them
because of how terrible their proposals and behavior has been.

This is not traditional 5G, it's basically misusing satellite spectrum.

~~~
upofadown
It's more or less the same process where a developer buys land cheap and then
with the help of a corrupt government rezones that land to something more
valuable.

~~~
thoraway1010
Not totally the same - its worse.

The FCC licenses bandwidth, no one owns it.

The FCC can rezone, they generally then run an auction, keep lots of $$ for
the govt, and kick some back to others if needed especially if they force
folks like TV stations to move their station broadcasts.

Lightsquared 100% lied when they said they would use the spectrum to serve
100% of users with a sat service. That was a necessary process for the
original transfer (like for like use).

And the value they are getting is huge. 40MHz of nationwide bandwidth. Easily
worth 10Billion plus.

Be totally fine for FCC to rezone using a normal process, auction to normal
business at fair market value, protecting or compensating existing users.

------
MR4D
An interesting threat vector arises here for Huawei...

Ignore all the stuff about backdoors and such for a minute. I wonder if the
administration fears that Huawai could simply attenuate their cell tower
signals at a high wattage to disrupt all sorts of things.

I never thought of that before - "5G as a weapon".

Definitely a weird world. I need to start reading Judge Dredd again to start
getting caught up on the future.

~~~
sa46
You might like Ghost Fleet [1] (or [2] for more colorful review). Ghost Fleet
is essentially a white paper turned into a Tom Clancy style techno-thriller on
what war might look like between China and the United States. Tactics from
Ghost Fleet include:

\- Infected microchips from Chinese suppliers used to target and destroy the
US Pacific fleet.

\- Disabling GPS with anti-satellite missiles.

\- Cyber attacks to disrupt the DOD communications networks.

[1]:
[https://en.wikipedia.org/wiki/Ghost_Fleet_(novel)](https://en.wikipedia.org/wiki/Ghost_Fleet_\(novel\))

[2]: [https://morningconsult.com/2015/09/08/the-defense-wonks-
who-...](https://morningconsult.com/2015/09/08/the-defense-wonks-who-just-
killed-the-white-paper/)

~~~
matheusmoreira
Thanks for the recommendation.

> Infected microchips from Chinese suppliers used to target and destroy the US
> Pacific fleet.

Awesome, the ideas that are often posted here have somehow made their way into
fiction.

> Disabling GPS with anti-satellite missiles.

Just GPS? I'd expect surveillance and communications satellites to be much
higher priority targets.

------
kyrra
FYI, Mark Esper (U.S. secretary of defense) has a commentary piece in today's
edition of the WSJ about this, titled: "The FCC’s Decision Puts GPS at Risk"

[https://www.wsj.com/articles/the-fccs-decision-puts-gps-
at-r...](https://www.wsj.com/articles/the-fccs-decision-puts-gps-at-
risk-11588719423)

------
briandear
This is being framed as a military issue, but the reality is that this would
cause havoc with aviation as well, especially precision GPS approaches.

Reminds me of a similar issue from 2012:

[https://www.gps.gov/news/2012/02/lightsquared/](https://www.gps.gov/news/2012/02/lightsquared/)

~~~
neltnerb
I'm a little worried that GPS is so vulnerable that these satellites could
cause such disruption to be honest. This is satellite based, any country could
be approving this plan and the impact on GPS would still be present since
orbits go everywhere.

I guess I'd rather they just... not... I don't really even think the trade-off
in increased seemingly real health risk is worth making the cell network even
faster.

It's going to happen though, if there's no mitigation that makes GPS more
invulnerable to interference it will inevitably fail when actually needed.

~~~
sasasassy
Let me just point out that satellites don't necessarily orbit around the
world. They can be geostationary, and in fact they usually are I think. That
is why you will find most US GPS satellites over the US, most Russian
satellites over Russia, etc.

Also, signal disruption is already very common as a necessary precaution at
sensitive times and places. I think many military bases and other sensitive
places, like the Kremlin, have signal interference so they are very imprecise
to target with GPS-guided weapons.

~~~
duskwuff
GNSS satellites (GPS, Galileo, GLONASS, Beidou, etc) are not in geostationary
orbits. Being in a geostationary orbit would put them in fixed "locations" in
the sky, making them easily blocked by terrain and entirely unusable at high
latitudes.

GPS satellites are in MEO, at ~20 km MSL. Other GNSS satellites use similar
orbits.

~~~
duskwuff
(Just noticed a minor error: GNSS orbits are roughly 20k km, not 20 km!)

------
Negitivefrags
Is this even actually directly related to 5G? I mean a mobile phone can’t
connect directly to space satellite right?

The article says “Would allow telecom companies to deploy 5G networks”. Is
this satellite network for doing connnections between cell sites maybe?

If that’s the case, it feels like 5G is only tangentially related and only
included in story for click bait given that people seem to want to get mad
about 5G recently.

~~~
icegreentea2
Ligado (ex-lightsquare) product is a hybrid satellite terrestrial network. The
specific component that people are concerned about is their terrestrial
network which is very much a 5G creature (in so much at Ligado is marketing
themselves and this approval as a step forward for 5G and IoT).

~~~
mytailorisrich
It's not a 5G issue, it's a spectrum allocation issue.

~~~
icegreentea2
Fundamentally yes, but look at how both sides are trying to sell the issue. If
Ligado and the FCC are both pushing this spectrum allocation issue as a
question of helping 5G or not (and therefore hitching onto the we need 5G now
or else China will beat us wagon), then I'm completely sympathetic to opposing
coverage piling on the counter 5G bandwagon.

~~~
Junk_Collector
The counter 5G bandwagon seems to be largely comprised of conspiracy theories,
dubious health claims, and unqualified assertions that people don't want more
bandwidth. Why would you poison a legitimately important topic like spectrum
allocation with associations like that?

~~~
grawprog
Personally, I dislike how the conspiracy nonsense has kind of covered up the
actual criticisms of 5g that existed prior to suddenly everyone thinking it's
a great idea and if you don't, you're a conspiracy theorist.

I seem to recall this revolved around, questionable tangible benefits vs cost
of deployment, poor penetration of 5g signals through structures, a lack of
devices or internet plans to take advantage of 5g, and some other things that
just seem to have taken a back seat to all the bullshit.

~~~
duskwuff
One has to wonder if some of the nonsense criticisms of 5G (causes disease,
government conspiracy, etc) have been deliberately amplified to _drown out_
legitimate technical concerns.

~~~
ta17711771
Bingo...

------
_bxg1
I have yet to hear anyone who's not a telecom CEO or a politician say they
actually _want_ 5G

~~~
nxc18
I want 5G. There, you heard it. I’m not a telecom CEO and I’m not a
politician.

Edit: I want fast, reliable telecommunications everywhere I go. I want ultra
fast reliable telecom in crowded cities. I want cellular that is competitive
with cable internet. I want bandwidth available for IoT devices.

~~~
takeda
> I want cellular that is competitive with cable internet. I want bandwidth
> available for IoT devices.

It never will be though. Whatever frequencies you can do wirelessly you can do
over a wire without the interference of other users using the same frequency
at the same time.

Also a lot of promises 5G offers only sound good on paper. The higher
frequencies don't travel well through walls (that's why it uses lower
frequencies as well) and the maximum speed being talked can only be obtained
during tests, but in the real deployment it has to be shared over all users.

Another problem is that the speeds don't mean sh*t if we have the same data
caps, in fact higher speed is worse, because many applications will switch to
a higher bitrate and consume more data, even when there's no noticeable
difference on a phone.

~~~
leetcrew
>> I want cellular that is competitive with cable internet. I want bandwidth
available for IoT devices.

> It never will be though. Whatever frequencies you can do wirelessly you can
> do over a wire without the interference of other users using the same
> frequency at the same time.

this is true in principle, but not necessarily in practice. I suspect it will
hold for the near/medium future, but I can imagine a world where much more
money is invested in improving mobile networks than home cable connections,
causing the latter to stagnate.

most "normal" people I know don't even own a desktop computer. there are no
devices in their homes that connect via ethernet (or even have an ethernet
port without a dongle!). at a certain point, it might make sense to ditch the
home modem/router altogether and scale up wifi networks to the point where
they basically merge with cellular.

~~~
state_less
I agree the internet is increasingly carried over radio these days (e.g. WiFi,
LTE, Satellite). Wireless still seems pretty young and crude yet. There seems
to be plenty of room to grow with respect to negotiating power levels,
frequency use, routing topologies and so on.

I think big fiber backhauls are still going to be a thing though.

~~~
leetcrew
> I think big fiber backhauls are still going to be a thing though.

absolutely, I'm just talking about wired vs. wireless as available to the
typical consumer. the fiber would be the backhaul for an entire city block or
neighborhood. just speculation.

------
kryogen1c
I don't understand this. Is the DoD not subject to FCC regulation? Are there
multiple bands that different types of GPS signals use (civilian vs military)?

My understanding of GPS was that it is used in _civilization critical_
applications like satellite synchronization and plane/ship navigation. How
could any sane human approve an interference with this traffic?

~~~
syshum
>>Is the DoD not subject to FCC regulation?

That is complex, but most likely no. Like the FAA they largely respect the
civilian agencies but ultimately they exist outside of that civilian
regulation

>>Are there multiple bands that different types of GPS signals use (civilian
vs military)?

Yes the military GPS is different from the Civilian GPS, the US DOD has the
ability in a time of war to cut off Civilian access to the GPS Network where
only US military (and approved Allies) receivers will work. This is one (of
many) reasons the EU, Russia and China all have their own GPS systems

>>How could any sane human approve an interference with this traffic?

While I do not know if I agree (have not read enough on the interference to
form a definitive opinion) the supporters of the new network claim there will
not be any meaningful interference, that the DoD is over reacting and if there
is Interference they will be required to replace the equipment..

~~~
stronglikedan
> the military GPS is different from the Civilian GPS

I remember reading at some point that the civilian GPS was randomly offset so
as not to give extremely accurate coordinates like the military GPS does. I
thought that was interesting, if true.

~~~
pdonis
The US used to intentionally degrade GPS signals available to civilian
receivers as compared with those available to military ones, but it stopped
doing that in the 1990s.

The biggest difference now between military and civilian GPS is that military
receivers use two frequencies, whereas most civilian ones only use one (since
using two costs more).

------
Causality1
I struggle to see the point of 5G existing at all when I can already burn
through the 22 GB data cap on my "unlimited" plan in an hour with 4G.

~~~
apcragg
The new standard supports more concurrent users by using the available
spectrum more efficiently. There are new modulation and timing "modes" that
enable better coverage at cell edges and in dense urban environments. There is
better support for multi-antenna systems which means better coverage and more
efficient spectrum usage. End-to-end latency has been dramtically reduced and
the next 5G NR iteration (rel 17) will add a super low-latency mode. There is
now a mode for IoT that enbales low-power communication. Most of these changes
aren't going to give you 1Gbps downlink speeds but they represent huge
improvements over even LTE-A.

------
tracer4201
Is it correct to say that this impacts GPS not only for the American civilian
and military but also the rest of the world?

What are other country’s thoughts? It would be interesting to learn what led
the FCC to make the decision they did... how did they deem the safety or
consequences of this decision, etc. hopefully it’s not driven purely by profit
incentives that put lives at stake.

Disclaimer: I have no background on GPS, whichever wave “band” the issue
impacts, or much of any technical understanding of the topic at all. Casual
observer.

~~~
reubenmorais
The company wants to build a 5G network in the US, so it would affect GPS in
the US. It's interference at the receiver, not at the GPS satellites
themselves.

~~~
kevindqc
My understanding of this is that the company wants to use L band, which is the
designation for the range of frequencies in the radio spectrum from 1 to 2
gigahertz (GHz)

Doesn't 5G use higher frequency than that?

Is the company, a satellite company, trying to use their satellites to provide
5G or something? So if the interference starts at the satellites, it could
affect other parts of the world?

>“We have presented to the FCC a proposal to utilize our terrestrial midband
spectrum as a greenfield opportunity that is aligned with the commission’s
stated goals of providing the foundation of the 5G future,” explained Doug
Smith, Ligado president and CEO. “By deploying 40 megahertz of smart capacity
on midband spectrum, we can create a model of at least a partial 5G network —
a next-generation, hybrid satellite-terrestrial network — that will enable 5G
use cases and mobile applications that require ultra-reliable, highly secure
and pervasive connectivity.”

~~~
madengr
5G is a very broad term, which is supposed to offer 10x performance in all
metrics over 4G.

This seems to be the same issue when they were called Light Squared. The
L-band was to be used for terrestrial base stations with very high power
transmitters. The issue is that, even though several MHz away, from the GPS
carrier, the transmissions will compress the LNA on GPS receivers with poor or
little filtering, desensitizing the GPS receiver.

Most civilian stuff now has decent filtering prior to the LNA so it can co-
exist with all the other wireless crap crammed in your phone.

I’m an RF EE and do a lot with GPS.

------
niftich
See document FCC-20-48 [1] for full text. Some quotes:

 _" Our decision authorizes Ligado to deploy a low-power terrestrial
nationwide network in the 1526-1536 MHz, 1627.5-1637.5 MHz, and 1646.5-1656.5
MHz band (...)"_

 _" Our action provides regulatory certainty to Ligado, ensures adjacent band
operations, including Global Positioning System (GPS), are sufficiently
protected from harmful interference (...)"_

 _" Ligado's amended license modification applications significantly reduce
the power levels of its operations from its earlier proposals and commit
Ligado to providing a significant guard-band in the MSS spectrum to further
separate its terrestrial transmissions from neighboring operations in the
Radionavigation-Satellite Service (RNSS) allocation. Based on the extensive
record, we conclude that Ligado's latest proposal—combined with the stringent
conditions we adopt today—addresses harmful interference concerns with respect
to GPS operating in the adjacent RNSS allocation, as well as concerns with
respect to MSS licensees' operations in the L-band."_

Read section "II. Background" for more technical info and changes since the
LightSquared proposals.

[1] (PDF)
[https://docs.fcc.gov/public/attachments/FCC-20-48A1.pdf](https://docs.fcc.gov/public/attachments/FCC-20-48A1.pdf)

------
skoskie
> ... and to repair or replace at Ligado’s cost any government device shown to
> be susceptible to harmful interference.

Boy, if that’s the actual text (it isn’t) of the contract, they need new
lawyers.

------
tonyztan
There also seems to be concerns that 5G may interfere with weather satellites:
[https://www.nature.com/articles/d41586-019-03609-x](https://www.nature.com/articles/d41586-019-03609-x)

------
beams_of_light
While sometimes considered controversial for decisions made on intangible
things like net neutrality, I expect the FCC would have a much better
understanding of the electromagnetic spectrum than the military, and having
all of them approve this tells me they see no threat to GPS from Ligado's
spectrum use. Makes me wonder what the politics are behind this, especially
when I see someone like Jim Inhofe involved.

~~~
finnthehuman
>I expect the FCC would have a much better understanding of the
electromagnetic spectrum than the military

Why? The FCC is concerned with coordinating peaceful use of commercial RF
products (and experimentation that could lead to new commercial products). The
military operates in hostile RF environments, conducts Signals Intelligence,
and has to mitigate signal intelligence conducted against them. The demand for
the absolute cutting edge of RF expertise is all on the military side.

------
unethical_ban
I have not read up on it - I am no expert. However, this is the second
technology (first being weather radar) that 5G is reported to have
significant, negative effects on.

As a layman, I do wish we banned 5G entirely, assuming these assertions are
correct. There is a greater public interest than even faster cell
connectivity.

The wiki on 5G isn't bad - I now get that it is a tri-band negotiation, and I
assume it is the "high" band that causes the issues.[1]

How does Wifi 6 use the same spectrum as 5G mid, but get such higher
throughput?

And if the point of 5G is also to give higher speeds and capacity in dense
urban environments, with denser antenna coverage, why couldn't they adapt the
existing 2-6 GHz range instead of going up toward millimeter?

[1] - [https://en.wikipedia.org/wiki/5G](https://en.wikipedia.org/wiki/5G)

meta-edit: So, I put forward assertions, admitted humility and lack of expert
knowledge, asked questions and linked to a wiki that I found to talk about the
subject. If the person/people who downvoted me for the original content sees
this, please note that the downvote button is not a disagree button. If you
have substantive issue with the post, rebut it.

~~~
pavon
The problem has nothing to do with 5G inherently, and the vast majority of the
bands it is approved to operate on will have no interference issues. The
problem is that the current FCC has been very bullish on opening up more bands
for mobile use even if there are legitimate interference concerns.

> And if the point of 5G is also to give higher speeds and capacity in dense
> urban environments, with denser antenna coverage, why couldn't they adapt
> the existing 2-6 GHz range instead of going up toward millimeter?

They are. Eventually all the bands currently used for 4G will be migrated to
5G. If you see T-mobiles ads about the largest 5G network in the country, that
is all deployed on existing bands that were also approved for 4G. On these
bands 5G will be a minor upgrade.

The millimeter bands are intended to significantly increase the number of
concurrent users, but the places where it can be effectively deployed are very
limited. It won't pass through buildings, and has short range. As an example,
Verizon couldn't even cover a full sports stadium with a single tower, and
that's a prototypical case of where millimeter is supposed to be valuable.

This latest issue is completely separate. It is entirely about a single
company, Ligado, that bought spectrum adjacent to GPS at a discount deal
because it came with strict restrictions on how that spectrum could be used to
avoid interference with GPS. For years they have been trying to get the FCC to
relax those restrictions for various different purposes, and this FCC finally
approved. For previous requests there was tons of hard data filed showing that
the proposed use would absolutely cause interference, and the requests were
rejected. The latest approval does stipulate much wider guard bands and other
measures to decrease interference. I don't know whether these measures are
sufficient. The FCC commissioners unanimously think they are, while the DoD
brass is insistent that they aren't.

------
mirimir
Couldn't the FCC just rescind approval if there's interference with GPS? Or at
least, with DoD GPS?

------
herdodoodo
>U.S. Space Force Gen. John Raymond told the Senate Armed Service Committee

>U.S. Space Force Gen.

I know it's unrelated, but it is very strange seeing this title actually
written out.

~~~
zrail
"the Fourteenth Air Force/Air Forces Strategic was redesignated as Space
Operations Command (SpOC)."

Because of course the Space Force would have something named Spoc(k).

[https://en.wikipedia.org/wiki/United_States_Space_Force](https://en.wikipedia.org/wiki/United_States_Space_Force)

------
mLuby
Do they ever _not_ say that?

News would be "Pentagon official admits that <thing> doesn't actually threaten
national security of largest military on the planet."

------
brenden2
It's in the military's interest to limit the freedom and empowerment of the
public as much as possible. I would take their opinions with a grain of salt.

With that said, this seems like something that can be easily solved with
technology improvements.

~~~
souterrain
Excepting in this case where the military operates a critical, life-safety
infrastructure used by civilians.

I'm frankly more concerned with the FCC acting as a taxpayer-funded telecoms
industry cheerleader.

Dear FCC: You're regulators. You're supposed to be regulating. This is what
you get for being public servants.

~~~
brenden2
Meh, the military engages in far more life terminating than life saving.

~~~
kube-system
Deterrence is hard to measure, but US military superiority correlates with a
period of relatively low global conflict.

~~~
brenden2
Maybe so, but the evidence is weak at best. Some wars (like Iraq, Korea,
Vietnam) were a sham. I'd feel more comfortable knowing nobody had nuclear
weapons.

~~~
kube-system
You'd feel more comfortable, but is that the same as actually being safer?

~~~
brenden2
You could ask someone who was living in Japan in 1945.

~~~
carapace
Or someone living in Nanking in 1938.

