Air carrier Captain reported experiencing GPS jamming and/or spoofing while in cruise. The GPS was rendered inoperable for the rest of the flight and the flight crew had to use iPads for navigation.

Narrative

Just did my first OMDB flight in a long time. Both on the way there and on the way back; we were subject to GPS jamming/spoofing near Egypt/Israel/Jordanian airspace. NEITHER time did the jet recover either of the GPS receivers. We complied with the procedure in a pilot bulletin; including disabling GPS updating BEFORE entering the FIRs listed. I was not up there for the way into OMDB; but we never recovered GPS. On the way back; we witnessed alternating jamming/spoofing. We'd lose the GPS completely; then only one receiver would pick up a signal but it was stationary. At the same time; our iPads picked up the same stationary signal; showing us on the ground somewhere in Egypt. The jet receivers went blank again and my FO's iPad started getting a good signal. But my iPad was showing on the ground in Beirut of all places. Both iPads recovered a normal signal as we left Nicosia FIR.I don't know if it's a function - excuse my ignorance; as I'm not an expert here - of the Receiver Autonomous Integrity Monitoring (RAIM) or maybe information management system but it seems to me; the logic of the airplane may be that once it's gone long enough without a signal; or with conflicting signals that the 'brains' behind it all just throws that information out until it can be reset on the ground. I know I've had a situation where one of the Total Air Temperature (TAT) probes iced up and that's exactly what happened. It threw the information out; lost all thrust reference info; until such a time that the signals became valid again. The problem I'm trying to get to the bottom of is why the jet would not recover once the GPS signals became valid. Both of our $800 iPads recovered perfectly once leaving the area. One would think that our aircraft could do the same? I'd like to think there's a reset of some sort that could be done. The fact that our simple iPads could recover normally; but the aircraft is rendered GPS inoperable for the rest of the leg makes no sense to me.