[time-nuts] GPS Jamming in the UK

Rob Kimberley rk at timing-consultants.com
Tue Nov 13 14:52:00 EST 2007

C/A code was originally designed as course clock to allow P/Y code hardware
to lock on, and you should also note that latest generation P/Y hardware can
directly acquire and stay locked without C/A. In the event of a local or
Global conflict, C/A will be denied to some or all users.

The jamming tests undertaken may be part of testing new generation hardware
in high jam/non C/A scenario.

More info in Hugo Fruehauf's excellent paper which I've put on my web site.


(and yes, I know I need to remove the spaces in the title)

Rob K

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of GandalfG8 at aol.com
Sent: 13 November 2007 16:51
To: time-nuts at febo.com
Subject: [time-nuts] GPS Jamming in the UK

); SAEximRunCond expanded to false
Errors-To: time-nuts-bounces+rk=timing-consultants.com at febo.com RETRY

I've not come across this before and when a friend first  fowarded the link 
from another group I thought it was a spoof, and  still only half
but I've just copied this from the official  Ofcom Website in the UK...... 
"The Ministry of Defence conduct occasional tests on military  systems which

may result in some loss of service to civilian users of the Global  
Positioning System (GPS) including in-car navigation devices and networks
which  rely on 
GPS signals. Ofcom seeks to provide citizens and consumers with  information

about possible interruptions to these services via these email  updates
advanced notification of these tests. It must be emphasised that  this 
notification process only warns of future jamming excercises that are
brought to 
the notice of Ofcom and may not cover all jamming exercises. It  cannot be 
assumed that any loss of service is due to jamming exercises." 
There's an option to sign up for email notification..... 
Anyone come across this before or actually experienced any  identifiable 
jamming of signals? 
Nigel GM8PZR

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