Crj first officer reported experiencing faulty GPS input to onboard navigational displays.

Attributes
ACN	1641228
Time
Date	201904
Local Time Of Day	0601-1200
Place
Locale Reference	ZDC.ARTCC
State Reference	VA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Regional Jet 700 ER/LR (CRJ700)
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Component
Aircraft Component	GPS & Other Satellite Navigation
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine Flight Crew Instrument
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Track / Heading All Types

Narrative:

In flight; we got the FMS dr yellow alert on the mfd. We tried to reset our position using radio navigation several times. We were then alerted by ATC that we weren't heading towards dunfe as was indicated. They gave us a heading and said it looked like our GPS wasn't correct. Again; we tried to get our position using other navigation means; but it wouldn't reset our position. I then told ATC we were unable to use GPS and needed vectors. They complied and gave us headings to phl. Going into phl; we were given vectors to intercept the localizer for [runway] 27R; that looked 180 degrees off from what was showing in our mfd. We flew through the course and the captain lost his FD. ATC then gave us headings and altitudes and it appeared we lost dg. We continued with ATC using no gyro procedure to intercept the [runway] 27R localizer and complete the ILS 27R without incident to landing. We realized our GPS wasn't giving us accurate information during cruise. After consulting the FMS operators guide to reset our position using other navigation means; we tried to do that. After that; we asked ATC to vector us to the final destination.

Original NASA ASRS Text

Title: CRJ First Officer reported experiencing faulty GPS input to onboard navigational displays.

Narrative: In flight; we got the FMS DR yellow alert on the MFD. We tried to reset our position using radio navigation several times. We were then alerted by ATC that we weren't heading towards DUNFE as was indicated. They gave us a heading and said it looked like our GPS wasn't correct. Again; we tried to get our position using other NAV means; but it wouldn't reset our position. I then told ATC we were unable to use GPS and needed vectors. They complied and gave us headings to PHL. Going into PHL; we were given vectors to intercept the LOC for [Runway] 27R; that looked 180 degrees off from what was showing in our MFD. We flew through the course and the Captain lost his FD. ATC then gave us headings and altitudes and it appeared we lost DG. We continued with ATC using no gyro procedure to intercept the [Runway] 27R LOC and complete the ILS 27R without incident to landing. We realized our GPS wasn't giving us accurate information during cruise. After consulting the FMS Operators Guide to reset our position using other NAV means; we tried to do that. After that; we asked ATC to vector us to the final destination.

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.