Pewnie gdzies na swiecie intensywnie pracuja/pracowali nad sposobem
zakłócenia tych systemów. Ciekawe czy taki przekręt jest możliwy?
oczywiście że jest
Chodzi mi oczywiście o zakłócenie/wprowadzenie błędnych danych do
odbiorników tych systemów bez ich zniszczenia (odbiorniki i same satelity
pozostają sprawne).
Jakieś propozycje?
prosze, w nr 60 magazynu Phrack (www.phrack.com) pojawil sie artykul
prezentujacy opis budowy taniego i przenosnego zaklocacza GPS.
[Low Cost and Portable GPS Jammer ]
http://www.phrack-dont-give-a-shit-about-dmca.org/phrack/60/p60-0x0d.txt
oto wybrane fragmenty (pominalem czesc techniczna i konstrukcyjna)
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--[ 1 - Project Overview
A low cost device to temporarily disable the reception of the civilian
course acquisition (C/A) code used for the standard positioning service
(SPS)[1] on the Global Positioning System (GPS/NAVSTAR) L1 frequency of
1575.42 MHz.
This is accomplished by transmitting a narrowband Gaussian noise signal,
with a deviation of +/- 1.023 MHz, on the L1 GPS frequency itself. This
technique is a little more complicated than a simple continuous wave (CW)
jammer, but tends to be more effective (i.e. harder to filter) against
spread spectrum based radio receivers.
This device will have no effect on the precise positioning service (PPS)
which is transmitted on the GPS L2 frequency of 1227.6 MHz and little
effect on the P-code which is also carried on the L1 frequency. There may
be a problem if your particular GPS receiver needs to acquire the P(Y)-code
through the C/A-code before proper operation.
This device will also not work against the new upcoming GPS L5 frequency
of 1176.45 MHz or the Russian GLONASS or European Galileo systems. It can
be adapted to jam the new civilian C/A-code signal which is going to also
be transmitted on the GPS L2 frequency.
That said, it will work against the majority of consumer/OEM GPS
receivers, provided they are not setup in any advanced anti-jam
configuration.
---[ 2 - Why?
The onslaught of cheap GPS based navigation (or hidden tracking devices)
over the past few years has made it necessary for the typical citizen to
take up the fine art of electronic warfare.
Several companies[2] now sell "hidden" GPS based tracking devices which
mount inside or underneath your vehicle. Some transmit the coordinates,
via cellular phone, of your vehicle's present and/or past locations for
weeks at a time without battery changes or court orders!
Vehicle rental companies have been known to use GPS tracking devices to
verify you don't speed or abuse their rental vehicles. The unsuspecting
renter is often faced with these hidden abuse "fees" after returning the
rental vehicle.
Law enforcement agencies are dumb enough to keep track of house arrest
prisoners with simple GPS based tracking bracelets[3]. Some even use GPS
for automatic vehicle location (AVL) on their squad cars to allow the
dispatchers to send in the closest unit to a particular call or to know an
officer's location in case of an emergency situation where they can't use
their radio.
Cellular phone companies, trucking companies, private investigators,
toll-roads, aircraft, those "protect your child" systems and many more
services are all fully involved with the use of GPS based tracking. The
problem is, do you really want everyone to know where you are?
.
.
.
.
--[ 5 - Operation
Once the jammer is operational, you can practice testing it by monitoring
the signal on a common consumer GPS receiver or high quality communications
receiver. A GPS receiver close to the jammer will not be able to acquire
C/A-code lock and any operating GPS in the jammer's radiation pattern will
lose C/A-code lock. Higher quality GPS receivers tend to be less
susceptible to low power jamming, so you'll need to be in the antenna's
near-field radiation pattern (i.e. close) for it to work.
Any obstructions near the jammer's own antenna (trees, houses, hills,
walls, etc.) will decrease the jamming range. The best placement is where
the jammer's antenna is line-of-sight to the antenna of the GPS receiver
you're trying to jam. Real world results will vary drastically, but you
should be able to obtain a jam radius of a few hundred feet even in heavily
obstructed areas with the higher power (AH102) option and a simple antenna.
You can even practice counter-jamming methods to protect yourself against
hostile or accidental GPS jamming. Try to shield your GPS receiver from
the interference source by placing your body, trees, hills, rocks or other
obstructions in-between your position and the interference. More advanced
methods involve using directional or steerable phased-array antennas on
your GPS receiver (pointed skyward) to nullify any ground based
interference.
.
.
.
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Absolutnie nikomu nie polecam budowania czegos takiego.
Chyba nie musze wspominac o tym jakie to stanowi zagrozenie dla systemow
lokalizowania opartych na GPS. Jak ktos juz czuje wewnetrzna potrzebe
budowania czego takiego to uprzejmie prosze o nietestowanie tego urzadzenia
w poblizu lotnisk, obiektow wojskowych, statkow plywajacych ... itd.