illegal signals knocking out gps

Have anyone heard about illegal signals
knocking out GPS systems at the Newark Liberty International
Airport?

One suck source was a trucker with a cheap GPS jammer. He was
arrested. Idiot.
The FAA and airport authority are tracking those guys up.

Marcelo Pacheco

macpacheco writes:


Are you saying that an idiot in a truck with a cheap jammer was able to
disrupt all GPS navigation at an entire airport?

The interference was severe enough that the LAAS system was
transmitting a DNU - do not use message. The highway in question
borders the airport. Notice that LAAS systems are extremely finicky
about received GPS signal, they'll trip if anything is slightly out of
spec, since their goal is to enable ultra accurate GNSS navigation -
down to 1 meter protection level, which translate to about 10cm real
time kinematic performance (protection levels are worst case
algorithms, that typically overestimate errors). So any interference
that can cause any noticeable distortion to the GPS signal probably
will trigger LAAS transmiting DNU.

The jamming platform being tested off the coast of FL/GA wouldn't need
more than 25W radiated power to jam GPS signals at the stated range
(500km away at altitude, 300km away on the ground). AEGIS radar
systems have a total multi MW transmission strength.

Taken from AVWEB http://www.avweb.com/news/avionics/182754-1.html :

"Sensitive =3D Vulnerable
GPS is particularly vulnerable to jamming, because the receivers are
exquisitely sensitive -- they have to be, to receive the extremely
weak signal from orbiting satellites. A relatively low-powered jammer,
transmitting static on the GPS frequency band, can overpower
legitimate GPS signals over a wide area -- as much as a 100 kilometer
circle at just 1 watt radiated power. (By comparison, typical general
aviation Mode-C transponders radiate hundreds of watts.)"

That's the reason why eLoran was so important, and why the Obama
administration committed a huge mistake by its decommissioning. With
eLoran + dual frequency/multi constellation WAAS, it would have been
ok to deactivate all VORs, DMEs and CAT I ILSs nationwide. eLoran
could have paid for itself with the savings FAA would realize alone.
While GPS signals reach users in the ground or at typical aircraft
altitudes with a very weak signal, the weakest Loran-C towers transmit
a 11kW signal, and some Loran-C installations transmit a MW strong
signal, try jamming that !

Enough said. Marcelo

The reference station for GPS aided landing system at Newark is
installed directly adjacent to the New Jersey Turnpike, a very busy
highway that's a major artery of the illegal drug distribution
network. So, it's shouldn't be surprising that jammers are appearing
there to thwart GPS tracking by law enforcement. Of course, there are
many other motives for jamming, mostly not intended to purposely
disrupt aviation.

By all accounts, these ground based augmentations normally work
extremely well. Interference incidents highlight the dangers of over
reliance on GPS.

--- CHAS