An air carrier pilot reported GPS jamming over the Pacific Ocean.

Narrative

While enroute we experienced the loss of single and both GPS intermittently. The first indication occurred at approximately N34 W156. It continued to occur until about 115 nm south of ODK [VOR] (Kodiak AK).From the points specified above we had intermittent GPS loss of signal (single and both) which resulted in an EICAS for L/R ATC. Around N52 W154 we had a brief single FMC timeout (R; 10-20sec) and resulted a re-sync. Approximately 20-30min later we received an EICAS for UNABLE RNP. The re-sync seemed to have created a slow and increasing ANP in the right FMC. ATC (KZAK) was notified via CPDLC and their response was just to keep Anchorage informed since we were due to switchover soon. As the GPS signal returned and DME/DME updating became available the R FMC position corrected and the UNABLE RNP; L/R ATC EICAS disappeared. No noticeable navigation error (aircraft physically shifting position) occurred.Maintenance was notified and logbook entries made. Overall GPS jamming is not a surprise but the location of this did surprise me.