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Intel Brief on GPS spoofing and jamming in Aviation


 

Route most commonly known for GPS Spoofing

 

Date: 26/09/2023

Where:

  • Worldwide, current hotspot in ORBB/Baghdad FIR


Who’s involved:

  • Aviation worldwide, local governments, local non-state actors.


What is happening?

  • Where with GPS jamming, the GPS signal is interrupted to a degree that it is unusable, with GPS spoofing, a false GPS signal is broadcasted, causing GPS systems to produce false positioning without a warning shown to the pilots.

  • With GPS spoofing, a falsified GPS signal is received by the aircraft, which is of sufficient strength and integrity to fool aircraft systems, and will render an aircraft's IRS unusable in minutes, and has often resulted in the complete loss of navigational capability of the aircraft (OPSGROUP). Navigation systems are unlikely to produce warnings for spoofing compared to jamming, as the systems do not detect spoofing.

  • GPS spoofing in ORBB/Baghdad FIR has resulted in up to 80 nm deviation from the flight path. To OPSGROUP alone, twelve separate reports have come in quick succession from a range of aircraft platforms, from 777s to 8Xs, all affected by spoofing. The reports mentioned the crews noticing other aircraft in their vicinity also affected by the spoofing (OPSGROUP).

  • Aircraft affected by the spoofing in ORBB had to rely on radar vectors from ATC (OPSGROUP).

  • GPS jamming happens above the Baltic Sea, Eastern Finland, the Black Sea, and the Eastern Mediterranean, affecting major Europe to Middle-East and Asia routes.

  • Spoofing does not always have to happen from the ground. Airborne spoofing originating from ‘normal’ aircraft as well as UAVs are both feasible.

  • GPS spoofing development is further discussed at the bottom of the article.


Analysis & recommended mitigating practices:

In most modern aircraft, GPS is integrated in their navigational systems and lacks stand-alone, self-contained INS and IRS systems. Make sure to check your AFM to check where your aircraft navigational capability is based on. If your company hasn’t designed a contingency procedure yet on how to deal with this situation, here are a few steps you could undertake to be aware of the problem and mitigate it.


Mitigation actions before and during the flight:

  • Check enroute FIR NOTAMs for any reported GPS spoofing and (https://gpsjam.org/)

  • Cockpit Preparation: Perform full IRS alignment if entering a known area with GPS spoofing risk

  • Be aware of typical sensor hierarchy for FMS position: GPS, then IRS, DME/DME, VOR/DME, and DR.

  • Consider de-selecting GPS sensor input if option is available.

  • Perform a time check and set the correct time on a personal device or watch.

  • When flying through known areas of GPS spoofing, make a habit of logging your position at regular intervals and cross-check using dead reckoning.

  • Inform ATC when navigational accuracy is degraded significantly or this is suspected.

Recognition of being spoofed.

  • Loss of GPS integrity

  • FMS position error

  • Map shift on your PFD / MFD

  • Large increase in your Estimated position uncertainty (EPU).

  • Incorrect UTC time displayed on your FMS or cockpit clock

  • Other aircraft reporting position errors on 121.5


Do not solely rely on ATC to provide vectors in case of navigational issues during a jamming or spoofing occurrence. Make sure that you know how to apply dead reckoning as an alternate means, it is hardly taught and practiced in the current initial pilot training era.


Example of aircraft relying solely on GPS input for positioning.

The Embraer Phenom 300, like the Cessna Citation CJ3+/M2 is equipped with a Garmin 3000 and relies solely on GPS input for positioning. If both GPS signals are lost, the aircraft does not have a conventional backup for the FMS to have positional information. The VOR and DME can be used for conventional navigation but cannot be linked to the Garmin FMS.


The AHRS takes a signal feed from the GPS, Magnetometer, and Air Data, and if any of these are interrupted, an AHRS FAULT CAS is seen by the crew, which means the AHRS is working in a degraded mode of operation.


Some or all of the following annunciations or CAS messages will be seen on the Garmin 3000 in the event of a loss of GPS signal.


  • GPS LOI (PFD)

  • BOTH ON GPS 1/2 (PFD)

  • TAWS N/A (SVS NOT AVAILABLE) (PFD)

  • AHRS 1/2 FAULT (CAS)

  • WSHEAR NOT AVAIL (CAS)

  • ADS-B NOT AVAIL (CAS)

  • NO FMS POSITION (MFD)

  • GPS NAV LOST (GTC)

  • AHRS 1/2 GPS (GTC)

  • DR (HSI)


Note: Dead Reckoning Mode (DR) only functions in enroute (ENR) or Oceanic (OCN) phase of flight. In DR Mode, the system uses its last-known position combined with continuously updated airspeed and heading data (when available) to calculate and display the aircraft’s current estimated position.


In all other phases, an invalid GPS solution produces a ‘NO FMS POSITION’ annunciation on the map, and the system stops using GPS.

If any of the above messages are presented, and GPS integrity is suspected, the following QRH checklists should be followed:


  • GPS NAV SYSTEM FAILURE - NAP1-18

  • AHRS 1/2 FAULT


This checklist must be followed to slow the aircraft down to prevent a possible AHRS mis-compare limit from being exceeded, which could lead to an AHRS FAIL situation.

Note: Ventral rudder availability has been improved to depend on AHRS yaw rate values only. Previously, it also required the use of roll parameters. In practical terms, later oscillations will not occur when AHRS are operating in alternate mode.

Additional Actions

  1. Check the GPS Status Page (Utilities / GPS Status) on the GTC and the detailed information shown on the PFD when this page is selected on the GTC.

  2. Identify the failed sensor, cross-check aircraft position using VOR / DME.

  3. Monitor aircraft position and navigation performance.

  4. Inform ATC when navigational accuracy is degraded significantly or this is suspected.


GPS spoofing (Garmin 3000) is an attempt to deceive a GPS receiver by broadcasting incorrect GPS signals. These signals may cause a complete failure of GPS, similar to GPS jamming, or cause the GPS position to shift from the actual position. As GPS is the primary position sensor, the FMS position will shift with the GPS position. Depending on the rate of change of GPS position, this shift may not be detected automatically.

The following are potential indicators of GPS spoofing:

  • GPS LOI

  • NO FMS POSITION

  • LOSS OF GPS NAVIGATION (GTC)

  • Map shift on PFD / MFD

  • Excessive deviation between FMS position and conventional navigation sources.

Inform ATC when navigational accuracy is degraded significantly or this is suspected.





GPS Spoofing Development

The surge in GPS jamming and spoofing incidents within the Iraqi FIR, along with their widespread occurrences, strongly indicates the involvement of an airborne platform (UAV).


In the past, Iran has successfully intercepted a drone by GPS spoofing.


Spoofing provides an attack vector that enables control over the target UAV (aircraft) without compromising the flight control software or the command-and-control radio link. Furthermore, a GPS spoofing attack can be carried out by an attacker who is equipped with an RF transmitter that can be ground or airborne-based.




 

Peace of mind


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