Ted wrote:

"Jim Carter" wrote in message
.com...




-----Original Message-----
From: ]
Posted At: Sunday, February 12, 2006 5:53 AM
Posted To: rec.aviation.ifr
Conversation: GNS430 on the Airway
Subject: GNS430 on the Airway

ted wrote:


wrote in message


news:%_hHf.33984$JT.6861@fed1read06...


...clipped for brevity...
[Jim Carter]


Continuity means the reliability of the primary GPS sats themselves.
They can have a sat failure or, more likely, jamming.


[Jim Carter]
Unless control of the satellite management system can be achieved, and
the entire constellation interrupted, wouldn't jamming be a localized
event based on the radiation pattern and power of the jamming
transmitter? And to continue jamming wouldn't the transmitter have to
stay active, making it a pretty easy target for any of several modern
weapons systems that don't rely on GPS for navigation?




http://www.fas.org/man/dod-101/sys/smart/agm-88.htm

http://www.vectorsite.net/twbomb8.html

HARM Block 3a and 5 software updates have completed testing and were
incorporated as a software only engineering change starting in August 1999.
The software improves missile performance against several threat
countermeasures...

The Advanced Anti-Radiation Guided Missile (AARGM) project is adding to the
Block VI capability by demonstrating technology for RF homing integration
with an active millimeter wave terminal seeker to provide a counter-shutdown
capability. Fielding this capability could be in the 2005 timeframe.

http://www.military-aerospace-techno....cfm?DocID=685

http://www.chips.navy.mil/archives/0..._files/GPS.htm

http://www.aeronautics.ru/news/news001/gpsnews001.htm

http://www.afa.org/magazine/May2003/0503road.asp
Threat to GPS Fizzled

The Great GPS Scare turned out to be a false alarm.

In the run-up to the war, some had expressed concern that Iraqi forces could
employ inexpensive jammers to disrupt the relatively weak signal emitted by
Global Positioning System satellites circling the Earth. Disruption of this
nature would have put a severe kink in USAF's ability to use GPS-guided
weapons and navigate in the desert.

However, the problem proved to be largely unfounded, as coalition forces
used GPS-guided weapons with impunity. DOD data shows that coalition forces
by April 5 had dropped more than 3,000 Joint Direct Attack Munitions, just
one type of GPS-guided weapon.

Early in the conflict, there were reports that Iraq had obtained several GPS
jammers, possibly from a Russian supplier. Maj. Gen. Victor E. Renuart Jr.,
Central Command operations director, announced March 25 that coalition
forces had identified six of these jammers and had destroyed all six.




The wink link in Air Traffic control is not GPS but communications. The
FAA still uses AM VHF
transmitters and receivers for AT communications. Very easy to jam and
disrupt. One idiot with one radio could
spread havoc around a major US airport. If the person stays mobile
virtually impossible to locate and detect.