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Measurement uncertainty and feasibility study of a flush airdata system for a hypersonic flight experimentPresented is a feasibility and error analysis for a hypersonic flush airdata system on a hypersonic flight experiment (HYFLITE). HYFLITE heating loads make intrusive airdata measurement impractical. Although this analysis is specifically for the HYFLITE vehicle and trajectory, the problems analyzed are generally applicable to hypersonic vehicles. A layout of the flush-port matrix is shown. Surface pressures are related airdata parameters using a simple aerodynamic model. The model is linearized using small perturbations and inverted using nonlinear least-squares. Effects of various error sources on the overall uncertainty are evaluated using an error simulation. Error sources modeled include boundarylayer/viscous interactions, pneumatic lag, thermal transpiration in the sensor pressure tubing, misalignment in the matrix layout, thermal warping of the vehicle nose, sampling resolution, and transducer error. Using simulated pressure data for input to the estimation algorithm, effects caused by various error sources are analyzed by comparing estimator outputs with the original trajectory. To obtain ensemble averages the simulation is run repeatedly and output statistics are compiled. Output errors resulting from the various error sources are presented as a function of Mach number. Final uncertainties with all modeled error sources included are presented as a function of Mach number.
Document ID
19940032870
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Whitmore, Stephen A. (NASA Hugh L. Dryden Flight Research Center Edwards, CA, United States)
Moes, Timothy R. (NASA Hugh L. Dryden Flight Research Center Edwards, CA, United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1994
Subject Category
Aerodynamics
Report/Patent Number
H-2010
NASA-TM-4627
NAS 1.15:4627
AIAA PAPER 94-1930
Meeting Information
Meeting: Applied Aerodynamics Conference
Location: Colorado Springs, CO
Country: United States
Start Date: June 20, 1994
End Date: June 23, 1994
Accession Number
94N37378
Funding Number(s)
PROJECT: RTOP 505-68-40
Distribution Limits
Public
Copyright
Public Use Permitted.

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