Crj-200 non flying pilot reported a system wide GPS and ads-B failure.

Attributes
ACN	1652993
Time
Date	201906
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Dusk
Aircraft 1
Make Model Name	Regional Jet 200 ER/LR (CRJ200)
Operating Under FAR Part	Part 121
Flight Phase	Taxi
Flight Plan	IFR
Component
Aircraft Component	GPS & Other Satellite Navigation
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Private Flight Crew Multiengine Flight Crew Instrument Flight Crew Commercial
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy Deviation - Procedural MEL

Narrative:

System wide ads-B and GPS failure. We noticed the ads-B failure; which was not needed for flight; but I didn't notice that GPS was unavailable until we were taking off. The captain then said that we didn't need it; and as we were taking off I didn't want to argue. I later looked up the MEL and learned that we did need it; captain still doesn't realize.system wide GPS failure today; dispatch only notified us that of the ads-B failure which the MEL allows; but we didn't realize that the whole GPS system was down as well. By the time I realized; we were released for departure and on the runway; and the captain said it was fine; and I thought to trust his knowledge. On the ground; I looked it up and realized we were in the wrong.if we were grounded; it would have been nice for dispatch to tell us; as it was a system wide thing.

Original NASA ASRS Text

Title: CRJ-200 Non Flying Pilot reported a system wide GPS and ADS-B failure.

Narrative: System wide ADS-B and GPS failure. We noticed the ADS-B failure; which was not needed for flight; but I didn't notice that GPS was unavailable until we were taking off. The Captain then said that we didn't need it; and as we were taking off I didn't want to argue. I later looked up the MEL and learned that we did need it; Captain still doesn't realize.System wide GPS failure today; Dispatch only notified us that of the ADS-B failure which the MEL allows; but we didn't realize that the whole GPS system was down as well. By the time I realized; we were released for departure and on the runway; and the Captain said it was fine; and I thought to trust his knowledge. On the ground; I looked it up and realized we were in the wrong.If we were grounded; it would have been nice for Dispatch to tell us; as it was a system wide thing.

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.