Crj flight crew reported a track deviation resulted when they lost their GPS departing fat airport.

Attributes
ACN	1447722
Time
Date	201705
Local Time Of Day	1201-1800
Place
Locale Reference	FAT.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Regional Jet CL65 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Climb
Route In Use	STAR YOSEMITE1
Flight Plan	IFR
Component
Aircraft Component	GPS & Other Satellite Navigation
Person 1
Function	First Officer Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Track / Heading All Types

Narrative:

We departed on the yosemite 1 departure. ATC gave us a heading and cleared us to frame intersection when able. We entered frame into the FMS and executed that entry. The aircraft appeared to turn toward the waypoint however ATC asked us if we were turning toward frame yet. At that point it appeared the GPS had lost position and we declared a lost signal to ATC and asked for vectors. We were not able to regain accuracy with the GPS and navigated on vectors and VOR tracking for the remainder of the trip.perhaps recognition of the issue before departure [would have mitigated this issue] had it become evident.

Original NASA ASRS Text

Title: CRJ flight crew reported a track deviation resulted when they lost their GPS departing FAT airport.

Narrative: We departed on the Yosemite 1 departure. ATC gave us a heading and cleared us to FRAME intersection when able. We entered FRAME into the FMS and executed that entry. The aircraft appeared to turn toward the waypoint however ATC asked us if we were turning toward FRAME yet. At that point it appeared the GPS had lost position and we declared a lost signal to ATC and asked for vectors. We were not able to regain accuracy with the GPS and navigated on vectors and VOR tracking for the remainder of the trip.Perhaps recognition of the issue before departure [would have mitigated this issue] had it become evident.

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.