Single-Antenna GPS-Based Aircraft Attitude Determination

A method for synthesizing aircraft attitude information from single-antenna GPS velocity measurements is described. The attitude information consists of flight path angle and roll angle about the aircraft velocity vector axis. This ‘pseudo-attitude’ is compared with the conventional attitude consisting of pitch and roll angle about the body axis. In addition, a pseudo-attitude display is presented that shows flight path angle and roll angle instead of the traditional pitch and roll information, thus yielding direct indications of the actual flight path state. Flight tests in a Piper Arrow aircraft demonstrated that pseudo-attitude is equivalent in performance to conventional attitude, with no subjective or objective differences between the two. The results show that a single-antenna GPS receiver provides a useful source of attitude information and consequently may be used as a backup attitude system or for fault diagnostics in redundant systems.