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Development, simulation, and calibra...

Ellsworth, Joel C.

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Development, simulation, and calibration of a flush air data system for a transatmospheric vehicle.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Development, simulation, and calibration of a flush air data system for a transatmospheric vehicle./
Author:	Ellsworth, Joel C.
Description:	171 p.
Notes:	Adviser: Stephen A. Whitmore.
Contained By:	Masters Abstracts International46-02.
Subject:	Applied Mechanics. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=1448043
ISBN:	9780549218203

Development, simulation, and calibration of a flush air data system for a transatmospheric vehicle.
Ellsworth, Joel C.

Development, simulation, and calibration of a flush air data system for a transatmospheric vehicle. - 171 p.

Adviser: Stephen A. Whitmore.

Thesis (M.S.)--Utah State University, 2007.

For most air vehicles, knowing the wind relative flight state (altitude, air velocity, angles of attack and sideslip) is necessary for safe flight operation. The wind relative air data state becomes critically important for gliding vehicles in order to ensure the vehicle has the proper glide range to reach the landing site. Traditionally, the wind relative vehicle state has been determined by using pitot probes and directional flow vanes. These instruments work well for speeds up to Mach 3, but tend to be "burned off' by high dynamic pressures and temperatures much beyond that point. The solution is to use a matrix of pressure ports mounted flush to the vehicle nosecap and an algorithm to compute the air data state from the measured pressures. This is known as a flush air data system. Flush air data systems have been in development since the 1980's, but have not been implemented for their ideal application of suborbital reentry vehicles because of unacceptable amounts of noise in the solvers at high altitudes. This is typically above 80,000 feet, although it depends on the pressure transducer. The source of this noise is primarily random signal noise in the sensors and bias errors distributed amongst the sensor ensemble, which play a greater role as atmospheric pressure drops and there effectively becomes nothing left to measure. However, the bias can be averaged out by increasing the number of sensors, and the noise tends to be symmetrically distributed about the true value and can be largely removed by using an inertial enhancement filter to blend in inertial data. This results in a far more stable algorithm output than exists for previously developed systems, and yields useful and accurate data through the entire flight path from launch through reentry to landing. While the algorithm can be largely generic and applied to virtually any vehicle, it must be calibrated to the airframe to be able to account for the effects of upwash and sidewash. The coefficients for this calibration can be determined either from wind tunnel testing, or from computational fluid dynamics modeling.

ISBN: 9780549218203Subjects--Topical Terms:

1018410
Applied Mechanics.

Development, simulation, and calibration of a flush air data system for a transatmospheric vehicle.
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005 20110704
008 110704s2007 ||||||||||||||||| ||eng d
020 $a 9780549218203
035 $a (UMI)AAI1448043
035 $a AAI1448043
040 $a UMI $c UMI
100 1 $a Ellsworth, Joel C. $3 1282331
245 1 0 $a Development, simulation, and calibration of a flush air data system for a transatmospheric vehicle.
300 $a 171 p.
500 $a Adviser: Stephen A. Whitmore.
500 $a Source: Masters Abstracts International, Volume: 46-02, page: 1033.
502 $a Thesis (M.S.)--Utah State University, 2007.
520 $a For most air vehicles, knowing the wind relative flight state (altitude, air velocity, angles of attack and sideslip) is necessary for safe flight operation. The wind relative air data state becomes critically important for gliding vehicles in order to ensure the vehicle has the proper glide range to reach the landing site. Traditionally, the wind relative vehicle state has been determined by using pitot probes and directional flow vanes. These instruments work well for speeds up to Mach 3, but tend to be "burned off' by high dynamic pressures and temperatures much beyond that point. The solution is to use a matrix of pressure ports mounted flush to the vehicle nosecap and an algorithm to compute the air data state from the measured pressures. This is known as a flush air data system. Flush air data systems have been in development since the 1980's, but have not been implemented for their ideal application of suborbital reentry vehicles because of unacceptable amounts of noise in the solvers at high altitudes. This is typically above 80,000 feet, although it depends on the pressure transducer. The source of this noise is primarily random signal noise in the sensors and bias errors distributed amongst the sensor ensemble, which play a greater role as atmospheric pressure drops and there effectively becomes nothing left to measure. However, the bias can be averaged out by increasing the number of sensors, and the noise tends to be symmetrically distributed about the true value and can be largely removed by using an inertial enhancement filter to blend in inertial data. This results in a far more stable algorithm output than exists for previously developed systems, and yields useful and accurate data through the entire flight path from launch through reentry to landing. While the algorithm can be largely generic and applied to virtually any vehicle, it must be calibrated to the airframe to be able to account for the effects of upwash and sidewash. The coefficients for this calibration can be determined either from wind tunnel testing, or from computational fluid dynamics modeling.
590 $a School code: 0241.
650 4 $a Applied Mechanics. $3 1018410
650 4 $a Engineering, Aerospace. $3 1018395
690 $a 0346
690 $a 0538
710 2 $a Utah State University. $3 960049
773 0 $t Masters Abstracts International $g 46-02.
790 $a 0241
790 1 0 $a Whitmore, Stephen A., $e advisor
791 $a M.S.
792 $a 2007
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=1448043