GPS interference simulation?
-
Hello, is the GPS interference (spoofing, jamming etc.) simulated in the Starship? I've seen that the GPS can fail using the in-tablet failure, but what about GPS loosing its position for a while or showing the wrong one, like IRL?
Hi!
If you're flying using the FMS rather than the GNS430, you might run into Dead Reckoning (DR) mode which is a degraded state of the FMS navigation system that occurs when the multi‑sensor navigation unit loses enough valid sensor inputs to accurately compute position. When the FMS is in DR, the aircraft's position is calculated by dead reckoning, based on heading and true airspeed (TAS) data, along with the last known position, without continuous updates from external sources like VOR, DME, or VLF/Omega.
During DR operations, the system should be used with caution. You'll need to cross‑check and update the system's position visually by referencing a ground point or using other installed navigation equipment such as VOR and DME as soon as possible. This condition is indicated on the navigation display (ND) by the yellow 'DR' message, which appears whenever the FMS is in this mode, alerting the pilot to the reduced accuracy.
For IFR operations using the FMS, the minimum equipment typically includes, for example, 1 VOR, 1 DME, and valid heading and TAS inputs or 3 VLF/Omega stations along with the same heading and TAS data. The loss of these sensors is the most likely cause for DR mode to activate, which degrades navigation to the point where you can't fully rely on the indicated position without frequent cross‑checks.
This is simulated in the BS Starship. Hope that helps!
Alan / From Brazil.
-
Hello, is the GPS interference (spoofing, jamming etc.) simulated in the Starship? I've seen that the GPS can fail using the in-tablet failure, but what about GPS loosing its position for a while or showing the wrong one, like IRL?
@Zajcek100 To keep this from getting too long, I've picked out a few relevant FMS or EICAS messages that may appear regarding degraded navigation modes.
The POSITION UNCERTAIN alert is an action‑required message that appears when the radio signals received by the system typically from VOR/DME or VLF/OMEGA stations don't match the position computed by the Flight Management Computer, indicating an inconsistency that requires the pilot to manually update the aircraft's position in the system.
The FMS/VLF POS DISAGREE alert is a more specific message related to very low‑frequency radio navigation. It illuminates when the difference between the FMS‑calculated position and the position determined by the VLF/OMEGA sensor exceeds a threshold of 2.3 nautical miles. It remains active until that discrepancy is reduced below that value, signaling that the long‑range radio system is providing a fix that doesn't converge with the rest of the navigation solution.
Finally, the FMS IN DR MODE message (as I explained above) is a status message indicating the worst‑case scenario for navigation. It means the FMS is not receiving adequate radio signals from any source whether VOR/DME or VLF/OMEGA forcing the system into Dead Reckoning mode, where it relies solely on the last known position, combined with magnetic heading and true airspeed, to project the current location. This degrades accuracy and causes the computed wind vector to freeze on the display until radio signals are restored and the system automatically reverts to primary mode.
The first two messages are alerts that call for corrective action by the pilot (updating the position in the system), while the third is a confirmation that the system has lost all external references and is operating only on internal dead‑reckoning data.
-
@Zajcek100 To keep this from getting too long, I've picked out a few relevant FMS or EICAS messages that may appear regarding degraded navigation modes.
The POSITION UNCERTAIN alert is an action‑required message that appears when the radio signals received by the system typically from VOR/DME or VLF/OMEGA stations don't match the position computed by the Flight Management Computer, indicating an inconsistency that requires the pilot to manually update the aircraft's position in the system.
The FMS/VLF POS DISAGREE alert is a more specific message related to very low‑frequency radio navigation. It illuminates when the difference between the FMS‑calculated position and the position determined by the VLF/OMEGA sensor exceeds a threshold of 2.3 nautical miles. It remains active until that discrepancy is reduced below that value, signaling that the long‑range radio system is providing a fix that doesn't converge with the rest of the navigation solution.
Finally, the FMS IN DR MODE message (as I explained above) is a status message indicating the worst‑case scenario for navigation. It means the FMS is not receiving adequate radio signals from any source whether VOR/DME or VLF/OMEGA forcing the system into Dead Reckoning mode, where it relies solely on the last known position, combined with magnetic heading and true airspeed, to project the current location. This degrades accuracy and causes the computed wind vector to freeze on the display until radio signals are restored and the system automatically reverts to primary mode.
The first two messages are alerts that call for corrective action by the pilot (updating the position in the system), while the third is a confirmation that the system has lost all external references and is operating only on internal dead‑reckoning data.
@alanfernandes Do you know what should I do to trigger the Position Uncertain or DR mode by myself?
-
The issue OP is trying to convey is GPS jamming or spoofing. Where you should be having a GPS signal but are not. In the case of jamming, the plane continues in radio updating if available, or Omega if not. DR if there's no valid position input. In case of spoofing, you'll get a map shift as the plane still thinks the GPS is valid. I doubt the Starship has software logic to dump the GPS value if it finds it's erroneous (that may trigger a Position Uncertain). Also, for GPS jamming, you'd need a simulation to activate it when in certain geographical areas. Neither are simulated in the Starship.
-
The issue OP is trying to convey is GPS jamming or spoofing. Where you should be having a GPS signal but are not. In the case of jamming, the plane continues in radio updating if available, or Omega if not. DR if there's no valid position input. In case of spoofing, you'll get a map shift as the plane still thinks the GPS is valid. I doubt the Starship has software logic to dump the GPS value if it finds it's erroneous (that may trigger a Position Uncertain). Also, for GPS jamming, you'd need a simulation to activate it when in certain geographical areas. Neither are simulated in the Starship.
@MD82 What I was trying to point out is what could be simulated based on the actual systems and even that, in itself, is already a massive leap in software complexity compared to the technology available at the time, and especially considering what BS has managed to implement.
GPS jamming and spoofing are real‑world threats that affect navigation systems in different ways. In a jamming scenario, the aircraft loses the GPS signal altogether, and the FMS will fall back to other available sensors like radio updating from VOR/DME, or Omega if equipped and eventually to Dead Reckoning if no valid position input is available.
In a spoofing scenario, the aircraft still believes it has a valid GPS signal, but the position being reported is false. That would cause a map shift, since the system has no way of knowing the data is corrupted unless there's specific software logic built in to detect and reject erroneous GPS values, which could potentially trigger a POSITION UNCERTAIN alert.
That kind of logic, however, is quite sophisticated. And on top of that, to properly simulate jamming, you'd also need a way to activate it dynamically for example, based on geographical areas where such interference is known to occur.
None of this is currently simulated in the Starship and honestly, that's understandable. Even what I've described here, as a baseline, represents a tremendous level of software complexity when you compare it to the technology of that era. And given what BS has already achieved with the systems they did model, it's still very impressive.
