Effects of Pressure Ports Layout on Angle of Attack and Sideslip Estimation in the Flush Air Data System

Flush air data system (FADS) have been successfully used on the nose tip of large manned/unmanned air vehicles instead of a traditional noseboom air data system. In order to integrate FADS with strapdown inertial navigation, high accuracy of angle of attack and sideslip is required. The estimated accuracy of angle of attack and sideslip in three types of FADS, which have different pressure ports layout, is compared using the nonlinear least squares theory. Evaluation function is provided to evaluate the accuracy of angle of attack and sideslip in different pressure ports layout. The results show that more sensors and radiation-type can provide high accuracy.

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Wind Tunnel Results for a Distributed Flush Airdata System

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-16-0242.1 ◽

2017 ◽

Vol 34 (7) ◽

pp. 1519-1528 ◽

Cited By ~ 7

Author(s):

Roger J. Laurence ◽

Brian M. Argrow ◽

Eric W. Frew

Keyword(s):

Wind Tunnel ◽

Least Squares ◽

Static Pressure ◽

Least Squares Method ◽

Angle Of Attack ◽

Pressure Sensors ◽

Nonlinear Least Squares ◽

Unmanned Aircraft ◽

Regression Methods ◽

Relative Wind

AbstractThe multihole probe (MHP) is an effective instrument for relative wind measurements from small unmanned aircraft systems (sUAS). Two common drawbacks for the integration of commercial MHP systems into low-cost sUAS are that 1) the MHP airdata system cost can be several times that of the sUAS airframe; and 2) when extended from the airframe, the pressure-measuring probe is often exposed to damage during normal operations. A flush airdata system (FADS) with static pressure sensing ports mounted flush with the airframe skin provides an alternative to the MHP system. This project implements a FADS with multiple static pressure sensors located at selected locations on the airframe. Computational fluid dynamics simulations are used to determine the airframe locations with the highest pressure change sensitivity to changes in the airframe angle of attack and sideslip angle. Wind tunnel test results are reported with nonlinear least squares and neural networks regression methods applied to the pressure measurements to estimate the instantaneous angle of attack and sideslip. Both methods achieved mean errors of less than . A direct comparison of the regression methods show that the neural network method provides a more accurate relative wind angle estimate than the nonlinear least squares method.

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MEASUREMENT AND ESTIMATION OF THE ANGLE OF ATTACK AND THE ANGLE OF SIDESLIP

Aviation ◽

10.3846/16487788.2015.1015293 ◽

2015 ◽

Vol 19 (1) ◽

pp. 19-24 ◽

Cited By ~ 3

Author(s):

Stanisław Popowski ◽

Witold Dąbrowski

Keyword(s):

Navigation System ◽

Velocity Measurement ◽

Inertial Navigation System ◽

Angle Of Attack ◽

Inertial Navigation ◽

Satellite Navigation ◽

Linear Velocity ◽

Estimation Methods ◽

Satellite Navigation System ◽

Sideslip Estimation

The paper presents issues concerning the estimation of the angle of attack and the angle of sideslip on a flying object board. Angle of attack and sideslip estimation methods which are based on measurements of linear velocity components of an object with the Earth’s coordinates and on attitude angles of the object are presented. Both of these measurements originate from the inertial navigation system, and velocity measurement is obtained from the satellite navigation system. The idea of applying inertial and satellite navigation for the estimation of attack and sideslip angles is presented. Practical comparison of these estimation methods has been conducted based on logged parameters of a flight onboard a Mewa aircraft. Development proposals for these methods are presented as well.

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