Skylane 182/RG Turbo Skylane/RG
Flight Crew Multiengine; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 200; Flight Crew Total 8250; Flight Crew Type 200
Situational Awareness; Physiological - Other; Fatigue
Airspace Violation All Types; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; No Specific Anomaly Occurred Unwanted Situation
Flight Crew Exited Penetrated Airspace; Flight Crew Landed As Precaution; Flight Crew Became Reoriented
Human Factors
I was enroute from ZZZ1 to ZZZ2 in a Cessna 182.  About 40 minutes from my destination at a cruise altitude of 7;500 MSL on the autopilot I began to feel a small amount of fatigue. I felt that if I could rest my eyes for a moment that would be okay.  I fell asleep almost immediately.  I awoke 30 minutes later inside the outer ring of ZZZ Class Bravo airspace.I immediately performed a 180 turn and exited the airspace; descended outside the airspace and proceeded to ZZZ1 which is my destination.  I did not have clearance to enter Class B airspace.As a professional pilot I take this event very seriously.  After some introspection of my errors I have identified two areas that need to be improved upon.My process for determining fatigue levels needs to be modified so that I have a greater awareness of my fitness to fly.  In the future I will land the plane at the nearest suitable airport when I feel the need to 'rest my eyes'.I was not using any TRACON services such as VFR flight following.  This omission was an unnecessary risk especially as I approached a busy airspace.  I will use some type of radar services whenever available.
C172 pilot reported feeling fatigued; closed eyes for a few moments to recover with autopilot on; but fell asleep and violated a Class Bravo airspace.