GPS Jamming

[watercraft]

I have extracted the relevant points from a document issued giving prior notice of GPS jamming sites this year. Issued by DSTL on 16 Feb 2007 (part of the MOD) this information just doesn’t appear available to the general public. I guess I’m posting this so we can spread the word.

Navigation Systems, Dstl Farnborough have been tasked by the DPA SANS2 to operate a series of small scale GPS jamming events at four different locations around the UK. Details of the dates and locations of these events are presented below.

Please will you arrange to notify this jamming request to appropriate government departments so that standard NOTAMs and NOMARs can be issued. The details of the jamming anticipated are as follows:

Trial Serial 1 Portreath (Cornwall)
a. Dates: The 7th June and 8th June 2007.
b. Times: Between 0800Z – 1600Z.
c. Location of jammers: Within 1km of WGS84 position: N50° 16.2’ W005° 16.4’.
d. Frequencies: 24 MHz bands centred around 1227.60MHz and 1575.42MHz.
e. Jammers: One 100mW ERP jammer on each frequency.
f.
2m AGL/AMSL Land areas with clear line of sight to the transmitter.
Sea areas to a maximum range of 11km from the transmitter.


Trial Serial 3 (South of Peterhead)
a. Dates: The 17th August 2007.
b. Times: Between 0800Z – 1600Z.
c. Location of jammers: Within 1km of WGS84 position: N57° 27.5’ W001° 48.4’.
d. Frequencies: 24 MHz bands centred around 1227.60MHz and 1575.42MHz.
e. Jammers: One 100mW ERP jammer on each frequency.

2m AGL/AMSL Land areas with clear line of sight to the transmitter.
Sea areas to a maximum range of 11km from the transmitter.

25m AGL/AMSL Land areas with clear line of sight to the transmitter.
Sea areas to a maximum range of 11km from the transmitter.

 

[peterb]

There is an interesting little anomaly here. AIS is required by the US as a security measure (they now require vessels down to 65 ft to be fitted). But AIS depends on GPS, not just for things such as SOG and COG, but more importantly for the accurate timing by which the 'slots' are arranged. If GPS is interfered with, then surely AIS gets lost as well?

 

[Oldhand]

AIS will still operate but with either meaningless position and velocity data or manually entered data (assumming the jamming is successful). Certainly won't provide real time tracking.

I expect the GPS jamming will be published by NM closer to the time and broadcast on Navtex.