Regional Jet 700 ER/LR (CRJ700)
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued Advisory / Alert; Flight Crew Requested ATC Assistance / Clarification
Environment - Non Weather Related; Human Factors; ATC Equipment / Nav Facility / Buildings; Aircraft
During cruise; we noticed that we were getting a message for FMS DR on MFD. We tried several times to reset position using other navigational means. We were queried by ATC if were we assigned a heading. We informed ATC that we were given direct to DUNFE which was what our MFD was showing; however; our position was in accurate. We informed ATC that our GPS navigation was inoperable. ATC assigned heading vectors all the way to PHL. As we prepared to intercept the LOC for [Runway] 27R; we did not have the correct course set and had to get vectors back for a second approach. The MFD was providing erroneous position indicating due to the faulty GPS positioning. ATC first detected us off course. The MFD was showing our position with a 40 mile error. Faulty GPS locating caused us to be off of our intended course. Complied with ATC instructions and flew assigned headings.
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.
CRJ-700 flight crew reported experiencing faulty GPS signal to navigation displays. ATC was informed and provided heading clearances.