Abstract: An improved navigation and display system especially suitable for small aircraft rapidly determines the attitude (roll and pitch) of an aircraft from measurements made by an inexpensive, single receiver and antenna responsive to signals obtained from a satellite positioning system, e.g., the Global Positioning System. In contrast to conventional attitude navigation systems, which determine and display conventional (body-axis referenced) pitch angle, the present system determines and displays the “pseudo-attitude” or stability axis roll and pitch (flight path) angle, so that the pilot has an instantaneous comprehension of the actual flight path angle of the aircraft without needing to correct for angle of attack as in conventional attitude information systems. A Kalman filter with a short (˜0.5 second) time constant provides data at a sufficient rate (e.g., ˜10 Hz) to enable real-time flight with the system.