Air data prediction from surface pressure measurements on guided munitions

The control of guided munitions over wide ranges of flight conditions has posed new requirements for estimating air data parameters. A common approach to meet the control stability margins and time response requirements is varying autopilot gains as a function of estimated air data parameters. A feasibility study to estimate air data parameters using flush-orifice pressure sensors has been completed. Wind-tunnel measurements of static pressure on sensors mounted on a representative missile nose were used. The primary objective of this study was to explore options for in-flight estimation of air data parameters using only the static pressure data base. The air data parameters of interest include Mach number, angle of attack, aerodynamic roll angle, and freestream pressure. An iterative process based on the differential corrections method was used to determine the air data parameters and expected error in the final estimates. Examples are given that provide sensitivity to pressure measurement noise and different sensor configurations. The air data estimates obtained with this method are suitable for autopilot gain scheduling over a wide range of flight conditions. (Author)