UK Aeronautical Information Services

NATS Swanwick, Room 3115

Sopwith Way,

Southampton, SO31 7AY

aissupervisor@nats.co.uk

http://www.ais.org.uk

01489 887462

AFS: EGGNYNYX

AIC for United Kingdom

Aeronautical Information Service

AIC

P 056/2021

Effective 01 JUL 2021

  NOTIFICATION OF GNSS JAMMING TRIALS: NAVWAR TRIAL SENNYBRIDGE 19 - 30 JULY 2021

1 — Introduction

1.1 In accordance with UK procedures for the control of non-operational jamming, this note gives notification of radio jamming and signal interference activity, to intentionally provide interference to Global Navigation Satellite System (GNSS) signals, including the Global Positioning System (GPS).
1.2 This Circular includes the details and locations of the GNSS jamming, description of the predicted effects and a point of contact for further information or in case of emergency.

2 — Dates, Times and Location

2.1  Date: 19 to 30 July 2021
2.2  Location: Jammers will be located within 10 KM from Lat/Lon 520053N 0033831W.
2.3  Time:
2.3.1 Low power jamming will be limited to the daily hours of 0800 and 1700.
2.3.2 High power jamming will take place between 1100 and 1700 within the period specified. Further details regarding the day/time will be promulgated by NOTAM.
2.3.3 Additional High power jamming will take place between 1100 and 1700 within the period specified. Further details regarding the day/time will be promulgated by NOTAM.
2.4  Duration and Pattern: Periods of pre-planned GPS jamming will take place at various times during the exercise.

3 — GPS Jamming

3.1 The areas within which a GNSS receiver is potentially likely to encounter jamming and/or interference with potential for incorrect readings is outlined below. No allowance is made for airframe masking or the reduction of antenna gain towards the horizon seen in all receiver systems. Therefore, the worst possible case for receiver vulnerability is considered.
3.2 Text describing the predicted GNSS interference areas is supplemented with coverage graphics, representing the interference effect on GNSS receivers at 5000 FT AMSL, 10,000 FT AMSL, 20,000 FT AMSL, 30,000 FT AMSL, 40,000 FT AMSL.
3.3 The impact estimated at each level identified should be assumed to extend as illustrated to the level below it. E.g: estimated coverage for 10,000 FT should be assumed down to 5000 FT. If further information is required on the interpretation of this data please contact the CAA using the contact information in section 5.1.
3.4 Predictions show that the coverage area where GNSS signals are likely to be affected is as follows:
3.4.1 Low Power GNSS Jamming coverage area

2 M AGL
Areas with clear line of sight to the transmitter site.

25 M AGL
Areas with clear line of sight to the transmitter site

75 M AGL
Areas with clear line of sight to the transmitter site

1000 FT AGL
Areas with clear line of sight to the transmitter site

5000 FT AMSL
To 60 NM in all directions

10,000 FT AMSL
To 60 NM in all directions

20,000 FT AMSL
To 60 NM in all directions

30,000 FT AMSL
To 60 NM in all directions

40,000 FT AMSL
To 60 NM in all directions

3.4.2 High Power GNSS Jamming coverage area

2 M AGL
Areas with clear line of sight to the transmitter site

25 M AGL
Areas with clear line of sight to the transmitter site

75 M AGL
Areas with clear line of sight to the transmitter site

1000 FT AGL
Areas with clear line of sight to the transmitter site

5000 FT AMSL
Up to 80 NM from the transmitter site within a 245° - 290° arc, up to 40 NM in all other directions

10,000 FT AMSL
Up to 110 NM from the transmitter site within a 135° - 290° arc, up to 40 NM in all other directions

20,000 FT AMSL
Up to 130 NM from the transmitter site within a 135° - 290° arc and up to 40 NM in all other directions

30,000 FT AMSL
Up to 130 NM from the transmitter site within a 135° - 290° arc and up to 40 NM in all other directions

40,000 FT AMSL
Up to 130 NM from the transmitter site within a 135° - 290° arc and up to 40 NM in all other directions

3.4.3  Additional High Power GNSS Jamming coverage area

2 M AGL
Areas with clear line of sight to the transmitter site

25 M AGL
Areas with clear line of sight to the transmitter site

75 M AGL
Areas with clear line of sight to the transmitter site

1000 FT AGL
Areas with clear line of sight to the transmitter site

5000 FT AMSL
Up to 80 NM from the transmitter site within a 245° - 305° arc, up to 40 NM in all other directions

10,000 FT AMSL
Up to 110 NM from the transmitter site within a 140° - 315° arc, up to 40 NM in all other directions

20,000 FT AMSL
Up to 130 NM from the transmitter site within a 135° - 330° arc and up to 40 NM in all other directions

30,000 FT AMSL
Up to 130 NM from the transmitter site within a 135° - 330° arc and up to 40 NM in all other directions.

40,000 FT AMSL
Up to 130 NM from the transmitter site within a 135° - 330° arc and up to 40 NM in all other directions

3.5 Impact area may exceed the maximum height represented and should be assumed to continue beyond the altitude specified as described for the maximum altitude listed.
3.6 The following frequencies will be affected:
1559 MHz – 1612 MHz (GNSS L1/E1 band);
1215 MHz – 1256 MHz (GNSS L2 band);
1160 MHz – 1214 MHz (GNSS L5/E5 band).

4 — Use of GNSS

4.1 Although GNSS equipment is an accepted means of compliance with B-RNAV and P-RNAV requirements, one of the conditions
of its use is that the aircraft must carry serviceable radio navigation equipment in order to allow reversionary means of navigation.
Operators of aircraft should not rely on GNSS for B-RNAV and P-RNAV operations in the areas predicted to be affected by the jamming trials and should be prepared to revert to the alternative means of navigation.
4.2 For IFR en-route and terminal area operations, only radio navigation equipment required by the rules for IFR operations should be used
4.3 For VFR operations, conventional means of navigation including dead reckoning should always be used.
4.4 Operators of aircraft should be prepared for erroneous readings if cross checking with GNSS in the area predicted to be affected by the jamming trials.
4.5 Air Traffic Controllers should be alerted to the potential for aircraft to require navigation assistance during the period of the trial.

5 — Points of Contact

5.1 General and non-urgent queries regarding these trials should be made in the first instance to:
Email: spectrum@caa.co.uk.
5.2 During the period of the exercise, the formal cease jamming contact number is:
01874-635599;
01980-953785.

Note: This number is only to be used in case of emergency in order to ask for jamming to cease. As with previous exercises, safetyof life operations will at all times take precedence over exercise activities.