Regional Jet 200 ER/LR (CRJ200)
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter CFTT / CFIT
Flight Crew Became Reoriented; Flight Crew Took Evasive Action
Aircraft
While on visual approach to we were maneuvering toward the runway when we received a terrain warning from the Ground proximity Warning System (GPWS). The aircraft's GPS was INOP and the FMS was intermittently flashing FMS Dead Reckoning Mode (DR) and Terrain not available. We appeared to be above the terrain but elected to comply with the warning and climb. Wen continued the approach without further event.The reported ceiling was 045 OVC with weather clearing from the area. The GPS being deferred left us not trusting the FMS and desiring to get on the localizer as soon as possible turning toward the airport which brought us closer to higher terrain. I will be less likely to accept a visual approach into ZZZ at night until I'm sure that I'm over the Ocean.
CRJ-200 Captain reported being dispatched with the aircraft's GPS INOP and the FMS intermittently flashing FMS DR and Terrain not available. During a night visual approach a terrain warning is annunciated and the Captain elected to comply with the warning.