[time-nuts] GPS Jamming in the UK

[Magnus Danielson]

From: Brooke Clarke <brooke at pacific.net>
Subject: Re: [time-nuts] GPS Jamming in the UK
Date: Tue, 13 Nov 2007 15:06:16 -0800
Message-ID: <473A2DE8.2010306 at pacific.net>

> Hi Rob:
> 
> It was my understanding that SA has been legislated away (mainly to promote 
> civilian GPS use) and so the military no longer has the option of turning SA on 
> to deny an enemy use of GPS.

So far they do, but they see that they have more selective options to use and
with future sats they don't need SA at all.

> So we are developing GPS jamming that will disrupt civilian/enemy GPS receivers 
> yet allow a crypto keyed US GPS receiver to function.  This would be done near 
> a battle zone and so would not effect the GPS system in other locations.

Certainly. There are also other sources of GPS jammers that can be used for a
versatile set of scenarios, which does not need to have classical military
uses.

GPS Jammers have been used by military to hunt gerilla forces. Had severe
sideeffect on civilian infrastrucute.

GPS Jammers have been used by military to protect against attacking forces.
Was defeated with GPS steered bombs.

GPS Jammers have been used by military on exercises and have not been disabled
when leaving the exercise area. Had severe sideffect on civilian
infrastructure.

GPS Jammers is available from multiple sources in multiple countries for
various types of uses. Include a number of sources on Internet for circuit
diagram. Such a jammer can jam a civilian GPS over 10 km away, as have been
tested.

Military have multiple times proved clueless on the modern society use of GPS
in a diverse fields, and has thus not cared to handle their jammers
accordingly. Some military people have cared, which is good, but there is
plenty of illusions to kill.

So while GPS is a lovely tool, but you need to protect yourself from the
situation where it is not there, and you need to be able to detect it. Galileo
and Glonass provide little additional protection. Also, if you protect yourself
from that, you also help to protect yourself from more mundane problems as
waterfilled GPS antenna (happend to me at work!) etc.

Cheers,
Magnus