Corporate jet Captain reported GPS jamming and spoofing while flying a RNAV arrival at an airport in the Middle East resulting in a course deviation. The Captain received vectors from ATC and utilized a ground based ILS and landed safely.

Narrative

We had read the NOTAMS of possible loss of GPS signal going into Amman terminal area and so briefed the weather and what to expect if we lost one or all GPS's. The engine start; taxi; takeoff; climb out; and cruise was uneventful apart from the passenger alerting us (Crew) that the event time was incorrect (one hour off). We briefed the expected runway ILS FOR 26R and set it up in the FMS and frequencies. We started our decent on the ELOXI 1C STAR Arrival. on the descent something seemed amiss! We had NO reason to feel this way although we both felt that things were not adding up such as our position FMS eta next position; it was simply just as if something was not as it should be. Amman ATC took us off the arrival at the transition level of FL150 and descended us to 6000 ft. on a Radar Vector of 340. eventually after two more vectors we were cleared direct to MIDRU the Initial Approach Fix (IF) However we were not cleared for the approach and so did not arm the Approach for 26R. Our Synthetic Vision (SV) disappeared. (An indication of loss of GPS) . We discussed the fact we had lost SV due to the loss of GPS and as we were coming up to MIDRU we would arm the Approach. We were cleared down to 5000 ft. the and 200kts this was the IF published altitude over MIDRU. It was VMC just 8 miles visibility I was head out looking for the airport (I was PNF) The I-NAV showed we were 15 miles south of MIDRU. I knew this could not be possible and the airport should be to our left not ahead and to the right. I looked at my LOC and it showed we had passed in inbound QDM of 256 inbound. At this point both of us were having problems understanding what was happening. The Auto Pilot was still engaged and the PF continued to monitor and fly the aircraft as I was trying to sort out what was happening between the INAV and the LOC. I was rechecking the ILS frequency when Amman Approach Control asked us where we were going? I said we show MIDRU ahead of us on our INAV. They said we think you are being 'Spoofed'. As we were unfamiliar with this term; I said we have lost our GPS. they said turn right direct to MIDRU; which we attempted to do. We executed this only to find that the INAV showed MIDRU now 42 NM South East of our position. ATC then vectored us to intercept the ILS 26R; which we did without issue. However the INAV still showed the airport South West of our position and stayed 42NM away without changing distance; even as we were supposedly flying away from where the INAV said we were. I selected RMI (Radio Magnetic Indicator) and VOR/ADF on my PDU and so was able to take a bearing and DME from 'Queen Alia VOR (QAA 115.20) to confirm our position. continued the approach. We made visual contact with the airport and runway and reverted to our SOP standard visual call outs per our Company SOP. We got the audio 'Terrain Terrain' on approach; which we ignore as obviously erroneous. other aircraft were calling into ATC saying they were being 'Spoofed' We departed 24hours later and informed ATC that we were 'Spoofed' on our arrival; and to keep an eye on us on our departure. We mitigated the impact of our departure by selecting ground base stations as part of this mitigating strategy. We did experience 'Spoofing' at 1400 ft. after takeoff loosing all GPS's and informed ATC we were being 'Spoofed'. Additional aircraft were also calling ATC notifying they were being 'Spoofed'. Causing us to fly via ATC headings through Jordon; Saudi Arabia; Egypt We did not regain GPS again until 1.1 after takeoff when we departed Egypt en route to ZZZZ.Suggestions: The NOTAM simply stated: Possible loss of GPS. This should be changed to WARNING PROBABLE LOSS OF GPS. This would have elevated our awareness to the very real probability of total loss of GPS due to GPS Jamming and or Spoofing! Perhaps we would have dug deeper into this new to us nefarious phenomena and at least become familiar with these terms. The passenger alerting us (Crew) that the event time was incorrect (one hour off) might have been the start of the GPS being corrupted due to erroneous wind inputs. Knowing what I now know about GPS Jamming and 'SPOOFING' As soon as we lost (SV) and thus GPS we should have immediately notified ATC and told them we could not guarantee our maintain our situational awareness; as we think we are being 'SPOOFED'! This would have immediately have put us on vectors by ATC. The INAV became very confusing regardless of getting a bearing radial from the VOR and DME. I have obtained guidance from the aircraft manufacturer by how to proceed if suspected future Spoofing"."