On Flight Path Reconstruction In the Absence of Angle of Attack and Sideslip Measurements

To address increasing demand for low-cost flight testing methodologies, this work was dedicated to establishing the feasibility and achievable performance of flight path reconstruction (FPR) methods that do not require flow angle measurements. Because the performance of such methods is highly coupled to the motion of the aircraft, a focus of this work was the establishment of the trajectory features that afford estimation performance comparable to conventional FPR methods. To elucidate such trajectory requirements, a trajectory information analysis based on the singular value of the linear time-varying observability Gramian was presented. Application of this analysis to a simulated maneuver revealed that flow angle measurement-free FPR methods may perform comparably with conventional FPR formulations when flight tests are designed with sufficient heading angle variation. These findings were further established through a comparison of the FPR trajectory estimation performance obtained using maximum a posteriori estimator implementations of both schemes. Losses in sideslip angle performance were identified as the most significant consequence of omitting the flow angle measurements, though acceptable performance was demonstrated under conditions of sufficient heading angle variation.