Narrative:

We were flying just north of white sands missile test at 33;000 feet. We started to get multiple intermittent eicam messages related to the GPS system. We notified ATC and they confirmed that the military was doing GPS jamming at white sands. Eventually; we lost both GPS units; (GPS primary fail) and developed a bad drift in our inertials (20+ miles). We confirmed the position error with our ipad GPS; VOR; and by radar position with ATC. Our nds showed us north of a NAVAID by 10 miles; when we were actually about 10 miles south of it. We disabled GPS input to the inertials; and used automatic radio updates to calm the inertial units down. Number 2 was still showing excessive drift; so we went to att reference on number 2; and switched the first officer displays to number 3. We called dispatch on the crew phone app; and had a group discussion with him and a rep from maintenance. The maintenance rep and the book had no way to get the GPS units back on line. Both units were showing blanks on their position ref pages. We were down to VOR navigation; and headings from ATC. We discussed diverting; but decided to press on after checking the weather and confirming with ATC that they could handle the additional work load of vectoring us; as we were unable to do any RNAV navigation. GPS jamming needs to be discontinued near commercial aviation. Had we been IMC or the weather had been worse at our destination; we would have had to divert. Our position was over 20 miles off of what was displayed on our screen. We confirmed this by the GPS in our ipads; VOR; and radar position with ATC.

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Original NASA ASRS Text

Title: An air carrier pilot reported losing both GPS units and was off course due to military GPS jamming.

Narrative: We were flying just North of White Sands Missile test at 33;000 feet. We started to get multiple intermittent EICAM messages related to the GPS system. We notified ATC and they confirmed that the military was doing GPS jamming at White Sands. Eventually; we lost both GPS units; (GPS Primary FAIL) and developed a bad drift in our inertials (20+ miles). We confirmed the position error with our IPAD GPS; VOR; and by RADAR position with ATC. Our NDs showed us north of a NAVAID by 10 miles; when we were actually about 10 miles south of it. We disabled GPS input to the inertials; and used automatic radio updates to calm the inertial units down. Number 2 was still showing excessive drift; so we went to ATT REF on Number 2; and switched the First Officer displays to Number 3. We called Dispatch on the Crew Phone App; and had a group discussion with him and a rep from Maintenance. The Maintenance Rep and the book had no way to get the GPS units back on line. Both units were showing blanks on their position ref pages. We were down to VOR navigation; and headings from ATC. We discussed diverting; but decided to press on after checking the weather and confirming with ATC that they could handle the additional work load of vectoring us; as we were unable to do any RNAV navigation. GPS jamming needs to be discontinued near commercial aviation. Had we been IMC or the weather had been worse at our destination; we would have had to divert. Our position was over 20 miles off of what was displayed on our screen. We confirmed this by the GPS in our IPADS; VOR; and RADAR position with ATC.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.