Originally Posted by
dClbydalpha
I suspect that neither RAIM nor a KF would prevent spoofing, in fact a KF would perhaps help the spoofer.
Some very good discussions here - earlier I (hope) I provided some useful info on the incident.
Again - hopefully this will help when looking at defences...The military often use what they call a CRPA (Conformal Radiation (some use "Reception" if you want to look online) Pattern antennas. Principle of these is that the antenna pattern steers nulls in the field in the direction of Radio Frequency interference at GPS frequencies. The antennas are typically 4 or 7 elements (determines number of nulls which is N-1 (where N=number of elements). As GPS signals come in below thermal noise - any signal the CRPA detects is regarded as interference and a null is formed in the direction of the source. They work really well and make it much harder for a spoofer (who now has to worry about setting very precise power levels which is difficult for all but most determined). I've been an advocate of these systems being made available to Commercial aviation( but only from my ground based knowledge of aviation) for a long time but so far restricted for military use only.. following is a very technical paper on how they work but I think explains some of the principals. I'd be interested in hearing your views on whether this kind of solution could work well enough for you on the flight deck....
https://web.stanford.edu/group/scpnt...-Jam_final.pdf