Between 22 and 26 September, a GPS jamming exercise will take place in UK, centred on the MoD Sennybridge Training Area, Powys, Wales.  Any GPS within line-of-site could be jammed out to 40 NM.

The land-based jamming will be carried out by QinetiQ on behalf of MoD, centred at around 5201N 00336W.

The jamming may take place between 0900 and 1800 daily for 3 minutes at a time totalling up to 3 hours per day.  Transmission will be restricted to a maximum of 3 minutes followed by at least 7 minutes of no transmission.

The directional jammer will radiate a maximum of 15 W EIRP.  Aircraft could be affected out to 40 NM within an arc 180°T clockwise to 90°T and to 27 NM in the remaining quadrant.

The CAA warns that although GPS equipment is an accepted means of compliance with B-RNAV requirements, one of the conditions of its use is that the aircraft must carry serviceable radio navigation equipment for reversionary means of navigation.

Details are in AIC 76/2008 (Pink 146) dated 14 Aug 08, available from NATS

Please let the Institute (director@rin.org.uk) know if you are affected by this jamming.