GPS jamming ethics

[Gawain 0]

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As far as I know we don't have anything like that for the GPS constellation.

Hmmm...perhaps that was addressed during one of the many "classified" shuttle missions of the 80s. Hey, you never know!

So I try and I scream and I beg and I sigh
Just to prove I'm alive, and it's alright
'Cause tonight there's a way I'll make light of my treacherous life
Make light!

[rhino 0]

You can't swamp a GPS signal.. When the device ONLY listens to a SPECIFIC signal that uses a SPECIFIC encryption. It isn't receptive to anything but what is encrypted..



You cannot jam it..

Rhino

[quade 3]

If somebody is trying to whisper a secret code word into your ear and I'm screaming the lyrics to "High Speed Dirt" in your ear at the same time -- will you be able to hear the whisper?

quade -
The World's Most Boring Skydiver

[Gawain 0]

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You can't swamp a GPS signal.. When the device ONLY listens to a SPECIFIC signal that uses a SPECIFIC encryption. It isn't receptive to anything but what is encrypted..

You cannot jam it..

The same could be said for a CDMA spread-spectrum cell phone. Yet signals can fade, shrink or be blocked due to a variety of natural phenominon. Despite the fact that the phone is designed to listen only to the "code" within the signal (hence C.ode D.ivision M.ultiple A.ccess). The platform does lend itself to be more tolerant of interference, but it is not impervious by any means.

If the weather can affect radio waves, then the encryption within the signal is thus useless.

Now throw 500,000 watts of the same signal noise and no device is going to hear anything. Regardless of code or encryption.

edited because I realized I didn't complete the post..

So I try and I scream and I beg and I sigh
Just to prove I'm alive, and it's alright
'Cause tonight there's a way I'll make light of my treacherous life
Make light!

[Zenister 0]

ding ding.. Quade wins..this is in simple terms EXACTLY how most basic jamming systems work..encryption or not the if the reciever cant 'hear' the signal thru all the extra noise it cant use that satellite to 'find itself'

fortunately it takes a good bit of energy to create enough noise to really disrupt the signal at any significant distance and that level of emission is easily targeted if nessesary..

____________________________________
Those who fail to learn from the past are simply Doomed.

[nathaniel 0]

> No you don't. All you have to do is put out enough power to swamp the original signal. You could do it with a spark gap transmitter and LC filter with enough power. (1900's technology.)

Swamp is an ambiguous word that I think hides part of the issue. It's not quite as simple as just talking louder than the GPS signal-- there are techniques that civilian GPS could use and military GPS surely uses that make it so the interference needs to be (several) orders of magnitude stronger than the GPS signal--to the extent that powering the devices over long periods of time becomes a real issue. Notwithstanding the fact that radio sources like GPS jammers are humongous "hit me" signs.

With GPS it's more than just a question of signal power, it's also a question of the physical source of the interference signal. Airborne interference sources imitating a satellite's relative spatial position don't need to be as strong as ground-based interference, but I would place the airborne route out of Iraq's playbook.

Key words in your point are "enough power", which IMO Iraq does not have in a war with the US scenario.

Nathaniel

My advice is to do what your parents did; get a job, sir. The bums will always lose. Do you hear me, Lebowski?

[kmcguffee 0]

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Sure, more of his own people are going to die because of it, but probably not him personally, AND the collateral damage and casualties will whip up more sympathy in other countries.

I think you hit the nail on the head. If he can use GPS jammers he will. He'll just use collateral damage and civilian casualties to whip up international resistance to the US. We can't afford to create too many civilian casualties so we will have to limit our attacks around populated areas. Next, Saddam will just move every weapon he can to a population center or move the population center to the weapon if necessary. Now we would have to send in more precision guided weapons, like the Rangers (HOOOAH!), which would cause an increase in US casualties and begin eroding the US will to fight.

IMHO.

"Any fool can criticize, condemn and complain and most fools do." Ben Franklin

[hagar 0]

I am sure that when bombs start hitting anything other than their intended target Saddams use of GPS jamming will be the official explanation even if the bomb where laser guided or not guided at all.

---
PCSS #10

[billvon 2,400]

>You can't swamp a GPS signal . . .

But Rhino, we _did_, accidentally, at an airport. I can swamp one in the lab, even ones that use the military (1227 mhz) slice of the GPS signal. I can take one of our secure phones (and they have very, very good encryption) and swamp that.

>When the device ONLY listens to a SPECIFIC signal that uses a
> SPECIFIC encryption. It isn't receptive to anything but what is
> encrypted..

That's true of many encoded signals. But that doesn't mean that you can't make enough noise to drown it out.

You may be able to talk to someone in a secret code and have no one else in the world be receptive to it. That doesn't mean that you can do it at a metallica concert, even if the code is very good. Don't confuse spoof-proof with jam-proof; they're not the same thing.

These are even available on the world market. See http://www.ac11.org/gps1.htm for a description of one such unit.

[billvon 2,400]

>With GPS it's more than just a question of signal power, it's also a
>question of the physical source of the interference signal.

We wish that were the case. Aircraft GPS antennas need to be fairly omnidirectional, since the satellite can be anywhere in the sky and the plane is not constrained to be flat vertically or horizontally. (If they did always fly flat, our jobs would have been a _lot_ easier.) Since they're fairly omnidirectional they can be jammed by sources on the horizon.

You can create a more directional antenna, at the cost of losing accuracy (fewer satellites, more 2D only fixes.) The problem is mainly one of distance. Satellites are 12,000 miles away; the jammer may be only 12 miles away. That means that even if the transmitters are the same power, the jammer's signal will be several orders of magnitude higher than the satellite signal at the aircraft. A 4 watt russian jammer has a claimed range of 150-200km for both airborne and ground based GPS's, which is not impossible with current (omni or hemispherical) antennas.

In any case, I agree that it's not that big an issue. We have enough navigation options that the loss of one won't cripple us - even if he does do it.

[bobsled92 0]

I can't wait to disrupt the GPS transmitter on my vehicle!
The asses call me on my cell phone to ask if I'm near a certain area or not too!
They chack 1 month later to see where you "were" nto to check for my saftey as to where we're all at!

_______________________________
If I could be a Super Hero,
I chose to be: "GRANT-A-CLAUS". and work 365 days a Year.
http://www.hangout.no/speednews/

[kmcguffee 0]

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I am sure that when bombs start hitting anything other than their intended target Saddams use of GPS jamming will be the official explanation even if the bomb where laser guided or not guided at all.

And I'm sure that if the US says it no one will believe it. If Saddam says absolutely anything, Europe and the Middle East will accept it with no second thought.

Isn't that how it works. Kind of funny when we're actually trying not to cause civilian casualties while Saddam, Omar, and UBL have done everything possible to increase civilian casualties. They target European civilians and place their own civilians in harms way for PR purposes. Then the US and UK get portrayed as the bad guys by the European media. What is worse is that people are buying into it. Makes me wonder about the reasoning ability of some people.

"Any fool can criticize, condemn and complain and most fools do." Ben Franklin

[rhino 0]

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If somebody is trying to whisper a secret code word into your ear and I'm screaming the lyrics to "High Speed Dirt" in your ear at the same time -- will you be able to hear the whisper?

An ear works that way. Receivers don't..


Rhino

[rhino 0]

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But Rhino, we _did_, accidentally, at an airport. I can swamp one in the lab, even ones that use the military (1227 mhz) slice of the GPS signal. I can take one of our secure phones (and they have very, very good encryption) and swamp that.

lol

Actually I believe the way the JADAM works is the GPS coordinates are pre programmed before the bomb is launched. The bomb knows what point on the terrain it is going to hit before it leaves the plane..

It PROBABLY isn't a continual feed of GPS signals. Internal map in the bomb, gps coordinates are entered, bomb puts an X on that part of the map and flies to it

Rhino

[quade 3]

Further musings and strategies.

Ok, so let's assume Saddam has the jammers and will use them. Let's further assume Saddam knows that they'll instantly become targets of some sort.

Then where would he put them?

My guess is that he'll place them on the rooftops of hospitals and mosques.

We know from looking at the fairly famous C-130 gunship video and elsewhere that we, the U.S., generally will NOT target religious sites and I'm guessing that Saddam also knows this. If we attempt to target the GPS jammers on top of hospitals and mosques, then that will whip up the absolute maximum support across the Arab nations against the U.S..

So, I'm thinking, these jammers do NOT get destroyed, but do, in fact, offer a small amount of protection is denying the U.S. the use of GPS based weapons and weapon platforms.

quade -
The World's Most Boring Skydiver

[quade 3]

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An ear works that way. Receivers don't..

That's EXACTLY how a radio receiver works.

quade -
The World's Most Boring Skydiver

[quade 3]

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It PROBABLY isn't a continual feed of GPS signals. Internal map in the bomb, gps coordinates are entered, bomb puts an X on that part of the map and flies to it

How a JDAM works -- HERE.

Jamming the GPS signal, which would be fairly easy, effectively denies the JDAM of its' pin-point targeting.

quade -
The World's Most Boring Skydiver

[Gawain 0]

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Further musings and strategies.

Then where would he put them?

My guess is that he'll place them on the rooftops of hospitals and mosques.

We know from looking at the fairly famous C-130 gunship video and elsewhere that we, the U.S., generally will NOT target religious sites and I'm guessing that Saddam also knows this. If we attempt to target the GPS jammers on top of hospitals and mosques, then that will whip up the absolute maximum support across the Arab nations against the U.S..

IIRC, during Desert Storm we had extremely well trained special units that were operating behind the lines before the first bombs fell. My guess is that those same assets would be in place before any other actions were taken and those assets may have tools which could disable or destroy those units without significant civilian casualties. Problem is, we want to avoid that, Saddam couldn't care less what happens to his "loyal" citizens.

So I try and I scream and I beg and I sigh
Just to prove I'm alive, and it's alright
'Cause tonight there's a way I'll make light of my treacherous life
Make light!