Learjet pilot reported navigational problems that were associated with the FMS; and GPS issues.

Attributes
ACN	1654220
Time
Date	201906
Local Time Of Day	0601-1200
Place
Locale Reference	LAS.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Learjet 35
Operating Under FAR Part	Part 135
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	GPS & Other Satellite Navigation
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 200 Flight Crew Total 28700 Flight Crew Type 300
Events
Anomaly	Aircraft Equipment Problem Less Severe Airspace Violation All Types Deviation - Procedural Published Material / Policy Deviation - Procedural FAR

Narrative:

We were flying our learjet from las to ZZZ on the SHEAD1 SID. During the en-route climb portion of our flight; at some altitude above 14;000 feet MSL; we were crossing shead intersection on coursed to dbige intersection. We monitored our autopilot as it flew the course. Our FMS/GPS navigational screen showed us on course. The la ARTCC called us and questioned our on course position. We showed that our aircraft was past shead intersection and on course. We continued on course; and later were advised to contact the la ARTCC supervisor by telephone when we reached our destination. During that conversation; he told us that the ARTCC controller observed an encroachment into restricted airspace. Our FMS/GPS depicted restricted airspace west of our on course position. From our conversation we arrived at a possible explanation to the situation; and that was that there may have been some GPS signal anomaly that occurred during that portion of the flight.

Original NASA ASRS Text

Title: Learjet pilot reported navigational problems that were associated with the FMS; and GPS issues.

Narrative: We were flying our Learjet from LAS to ZZZ on the SHEAD1 SID. During the en-route climb portion of our flight; at some altitude above 14;000 feet MSL; we were crossing SHEAD intersection on coursed to DBIGE intersection. We monitored our autopilot as it flew the course. Our FMS/GPS navigational screen showed us on course. The LA ARTCC called us and questioned our on course position. We showed that our aircraft was past SHEAD intersection and on course. We continued on course; and later were advised to contact the LA ARTCC Supervisor by telephone when we reached our destination. During that conversation; he told us that the ARTCC Controller observed an encroachment into restricted airspace. Our FMS/GPS depicted restricted airspace west of our on course position. From our conversation we arrived at a possible explanation to the situation; and that was that there may have been some GPS signal anomaly that occurred during that portion of the flight.

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.