Citation Excel (C560XL)
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Aircraft Equipment Problem Less Severe; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Clearance; Flight Crew Exited Penetrated Airspace; Flight Crew Overcame Equipment Problem
Human Factors; Aircraft
Flight plan was from LAS to ZZZ at 41000 ft.  Define flight plan was cowboy eight INW ZUN ONM CNX Q20 HONDS J15 CME SJT LLO.   Very close to the vicinity of the ONM waypoint the aircraft began to turn what we thought was the CNX waypoint.  In fact the aircraft turned to a heading of 180-185 and penetrated military Airspace of White Sands missile Range.  We were talking on frequency 132.65. The controller gave us headings to avoid White Sands Airspace. He then change those two frequency 132.07. That controller told us there was a possibility of a pilot deviation and we needed to call [ATC] upon [landing] to discuss the deviation.  In this area there was known GPS testing going on. This contributed to the deviation due to our degraded navigational capabilities of our GPS.  We told the controller on 132.07 that we were navigating on ground based navigation systems. He then gave us a heading when able directed to this San Angelo VOR.  GPS navigation was perfect after we departed the area that was testing GPS navigation systems.  We completed the flight and landed at [destination] airport with no further incident.  After landing I contacted [ATC] to discuss the incident. I explained the situation to him he looked at the radar track and said we had a deep clip [of] the edge of the White Sands Airspace but not by much. He then stated that he does not need any more information about it.Suggestions: When the Aircraft begins to make erratic turns in the air we should have immediately gone into a heading mode.  I didn't realize the GPS testing would cause such an issue with actual aircraft navigation. Aircraft should not be allowed to fly in this Airspace well testing is occurring.
CE-560XLS Captain reported GPS accuracy degradation during flight at FL410.