National Space Policy: NSDD-42 (issued on July 4th, 1982)

Sander Vesik wrote:

cott M. Kozel wrote:
(Stuf4) wrote:
From Scott Kozel:
(Stuf4) wrote:

Imagine during the biggest, most recent raid on Baghdad...

All of a sudden turning off GPS the constellation.

This would have had an effect reminiscent to that scene in a new Star
Wars episode where in the heat of battle, all of the robot warriors
instantly become useless.

Give it up, troll. The 1991 Gulf War utilized smart bombs without GPS,
so your assertions are false, as usual.

(By "biggest, most recent raid on Baghdad", I wasn't exactly thinking 1991.)

No difference. The 2003 Gulf War could have utilized smart bombs
without GPS, as well.

Really? want to poiint out any type of smart bomb that doesn't use satellite
technology that they could have used?

The laser-guided smart bombs which were utilized in abundance.

In sci.space.shuttle Scott M. Kozel wrote:
Sander Vesik wrote:

cott M. Kozel wrote:
(Stuf4) wrote:
From Scott Kozel:
(Stuf4) wrote:

Imagine during the biggest, most recent raid on Baghdad...

All of a sudden turning off GPS the constellation.

This would have had an effect reminiscent to that scene in a new Star
Wars episode where in the heat of battle, all of the robot warriors
instantly become useless.

Give it up, troll. The 1991 Gulf War utilized smart bombs without GPS,
so your assertions are false, as usual.

(By "biggest, most recent raid on Baghdad", I wasn't exactly thinking 1991.)

No difference. The 2003 Gulf War could have utilized smart bombs
without GPS, as well.

Really? want to poiint out any type of smart bomb that doesn't use satellite
technology that they could have used?

The laser-guided smart bombs which were utilized in abundance.

The JDAM guidance kits can also fall back to using onboard INS with only
a modest degradation of the CEP.
Of course, this relies on the planes INS, which is lots better than the
JDAM kit, but I have no idea how good most warplanes INS is.

Ian Stirling wrote:

Scott M. Kozel wrote:
Sander Vesik wrote:
Scott M. Kozel wrote:
(Stuf4) wrote:
From Scott Kozel:
(Stuf4) wrote:

Imagine during the biggest, most recent raid on Baghdad...

All of a sudden turning off GPS the constellation.

This would have had an effect reminiscent to that scene in a new Star
Wars episode where in the heat of battle, all of the robot warriors
instantly become useless.

Give it up, troll. The 1991 Gulf War utilized smart bombs without GPS,
so your assertions are false, as usual.

(By "biggest, most recent raid on Baghdad", I wasn't exactly thinking 1991.)

No difference. The 2003 Gulf War could have utilized smart bombs
without GPS, as well.

Really? want to poiint out any type of smart bomb that doesn't use satellite
technology that they could have used?

The laser-guided smart bombs which were utilized in abundance.

The JDAM guidance kits can also fall back to using onboard INS with only
a modest degradation of the CEP.
Of course, this relies on the planes INS, which is lots better than the
JDAM kit, but I have no idea how good most warplanes INS is.

Something else that hasn't been mentioned yet, is that GPS is easy to
jam, so the weapons need to have a fall-back internal or lasar guidance
mode if such jamming occurs.

In sci.space.policy Scott M. Kozel wrote:
Ian Stirling wrote:

Scott M. Kozel wrote:
Sander Vesik wrote:
Scott M. Kozel wrote:
(Stuf4) wrote:
From Scott Kozel:
(Stuf4) wrote:

Imagine during the biggest, most recent raid on Baghdad...

All of a sudden turning off GPS the constellation.

This would have had an effect reminiscent to that scene in a new Star
Wars episode where in the heat of battle, all of the robot warriors
instantly become useless.

Give it up, troll. The 1991 Gulf War utilized smart bombs without GPS,
so your assertions are false, as usual.

(By "biggest, most recent raid on Baghdad", I wasn't exactly thinking 1991.)

No difference. The 2003 Gulf War could have utilized smart bombs
without GPS, as well.

Really? want to poiint out any type of smart bomb that doesn't use satellite
technology that they could have used?

The laser-guided smart bombs which were utilized in abundance.

The JDAM guidance kits can also fall back to using onboard INS with only
a modest degradation of the CEP.
Of course, this relies on the planes INS, which is lots better than the
JDAM kit, but I have no idea how good most warplanes INS is.

Something else that hasn't been mentioned yet, is that GPS is easy to
jam, so the weapons need to have a fall-back internal or lasar guidance
mode if such jamming occurs.

GPS is almost trivial to jam.
I could build a jammer to kill military/civilian GPS within 10Km for
under $10 or so.
$100 and a balloon maybe 150Km.

The power over an entire hemisphere of the earth is some 50W.
It's trivial to swamp a reciever with some millions of times the nominal
signal.

In article ,
Ian Stirling wrote:
The power over an entire hemisphere of the earth is some 50W.
It's trivial to swamp a reciever with some millions of times the nominal
signal.

One caveat: it's not quite as easy as one might think, because the GPS
signals are *already* below the noise floor with typical antennas, and the
digital correlation method used to hear them anyway is quite robust. Just
raising the noise level somewhat won't do much. You have to either raise
it a whole lot, or get clever.
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

(Henry Spencer) wrote:

Ian Stirling wrote:

GPS is almost trivial to jam.
I could build a jammer to kill military/civilian GPS within 10Km for
under $10 or so.
$100 and a balloon maybe 150Km.

The power over an entire hemisphere of the earth is some 50W.
It's trivial to swamp a reciever with some millions of times the nominal
signal.

One caveat: it's not quite as easy as one might think, because the GPS
signals are *already* below the noise floor with typical antennas, and the
digital correlation method used to hear them anyway is quite robust. Just
raising the noise level somewhat won't do much. You have to either raise
it a whole lot, or get clever.

A nation at war (or about to go to war) could easily find the needed
resources to provide such jamming, though.

In article ,
"Scott M. Kozel" writes:
(Henry Spencer) wrote:

Ian Stirling wrote:

GPS is almost trivial to jam.
I could build a jammer to kill military/civilian GPS within 10Km for
under $10 or so.
$100 and a balloon maybe 150Km.

The power over an entire hemisphere of the earth is some 50W.
It's trivial to swamp a reciever with some millions of times the nominal
signal.

One caveat: it's not quite as easy as one might think, because the GPS
signals are *already* below the noise floor with typical antennas, and the
digital correlation method used to hear them anyway is quite robust. Just
raising the noise level somewhat won't do much. You have to either raise
it a whole lot, or get clever.

A nation at war (or about to go to war) could easily find the needed
resources to provide such jamming, though.

ANd thus provide a few zillion targetting beacons that will be
elimanated as the first course of business.

It's not at all as easy as you seem to think. Not only are the
signals hard to identify withing the noise, if you aren't a GPS
receiver, but, as far as the receiver is concerned, the signal's
highly directional. If it's not coming from above, and it doesn't
exhibit the propper doppler shifts, it's not a real signal, and can be
safely ignored.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

In sci.space.policy Peter Stickney wrote:
In article ,
"Scott M. Kozel" writes:
(Henry Spencer) wrote:

Ian Stirling wrote:

GPS is almost trivial to jam.
I could build a jammer to kill military/civilian GPS within 10Km for
under $10 or so.
$100 and a balloon maybe 150Km.

The power over an entire hemisphere of the earth is some 50W.
It's trivial to swamp a reciever with some millions of times the nominal
signal.

One caveat: it's not quite as easy as one might think, because the GPS
signals are *already* below the noise floor with typical antennas, and the
digital correlation method used to hear them anyway is quite robust. Just
raising the noise level somewhat won't do much. You have to either raise
it a whole lot, or get clever.

A nation at war (or about to go to war) could easily find the needed
resources to provide such jamming, though.

ANd thus provide a few zillion targetting beacons that will be
elimanated as the first course of business.

It's not at all as easy as you seem to think. Not only are the
signals hard to identify withing the noise, if you aren't a GPS
receiver, but, as far as the receiver is concerned, the signal's
highly directional. If it's not coming from above, and it doesn't
exhibit the propper doppler shifts, it's not a real signal, and can be
safely ignored.

Preceicely how does the receiver differentialte between signal coming
from the above vs. not? To differenctiate the source you need at least two
directional antennas. Not just that but air-balloons are cheap, increase
coverage abd would also be seen as being above by receivers.



--
Sander

+++ Out of cheese error +++

In sci.space.policy Henry Spencer wrote:
In article ,
Ian Stirling wrote:
The power over an entire hemisphere of the earth is some 50W.
It's trivial to swamp a reciever with some millions of times the nominal
signal.

One caveat: it's not quite as easy as one might think, because the GPS
signals are *already* below the noise floor with typical antennas, and the
digital correlation method used to hear them anyway is quite robust. Just
raising the noise level somewhat won't do much. You have to either raise
it a whole lot, or get clever.

I know.
I'm talking of raising the power recieved into a broadband reciever well
above the thousand or ten thousand times gain that the digital correlation
gives.
A 5W transmitter can hit a million times the power of a 50W global
transmitter at around a 4Km radius.
It will be very, very hard to generate a usable position even given
sharply directional antennas pointed at each satellite.

"Sander Vesik" wrote in message
...
Preceicely how does the receiver differentialte between signal coming
from the above vs. not? To differenctiate the source you need at least two
directional antennas. Not just that but air-balloons are cheap, increase
coverage abd would also be seen as being above by receivers.
And would be almost immediate targets for HARM missles.