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Rockwell Collins Inputs Turbulence Workshop #5 September 19-20, 2002 FAA LA-ACO. Topics. Collins Status Cert Tool Usage Certification Issues Needs from Turbulence Committee. Collins Status. Refinements of Standard Turbulence Detection Accomplished During MultiScan Product Development
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Rockwell Collins InputsTurbulence Workshop #5September 19-20, 2002FAA LA-ACO
Topics Collins Status Cert Tool Usage Certification Issues Needs from Turbulence Committee
Collins Status • Refinements of Standard Turbulence Detection Accomplished During MultiScan Product Development • Utilization of Flight Data from development flights • Noticed high rate of spectral widths at very short ranges • Good Correlation with Aircraft Encountered Turbulence • Models suggest less spectral width would be expected due to small beam volume compared with turbulence scale lengths • Expected Higher spectral widths at long ranges ~40 miles due to increased shear contributions – Actually see less • Measurement of turbulent regions at longer ranges may be diluted by higher reflectivity regions with uniform flow
Certification Tool Usage • ADWRS 5.1 Simulation Running • Preliminary Runs of 191-06 Data Set • Multiple Altitudes / Tilts • Long vs Short Tx Pulsewidths • Collins Detection Algorithm Interfaced to ADWRS Outputs • Writing Display Program to display ADWRS “Processed Data Output” • Dickinson ND Data Set not running yet • Array Size Problem
Observations So Far • Weak Correlation between High Sigma W areas (Proctor) and Radar Measured Spectral Width • Some High Spectral Width Areas Appear to be Dominated by Shear Early Research (J.T. Lee) found Turbulence “somewhere in the vicinity” of high spectral width and high reflectivity although not correlated in position
General Comments • Many Factors that Affect Radar Measured Spectral Width are Highly Situation Dependent • Eddy Size / Scale Lengths • Isotropic Turbulence vs Turbulence Driven by Adjacent Flows • Reflectivity of Non-Turbulent Region Within Beam Volume Dominates Reflectivity of Turbulent Region • Optimization of a Detection Process around a Limited Set of Environments and Assumptions Will Lead to a Non-Optimum Solution • Need a Large Sample of Events / Types
Test Case Scoring • High Vertical Sigma W is a Good Measure of RMS Aircraft Loads • However, Coupling of High Vertical Sigma(W) with Radar Measureable Sigma U is Uncertain • Obvious from Runs of 191-06 High Sigma W <==/==> High Sigma U • Will Be Difficult To Achieve Exact Overlay of High Vertical Sigma W with Radar Measureable Spectral Width • Detection Algorithms May Require Velocity Structure Function to Augment Spectral Width
Certification Cases • Need Large Number of Events to Encompass Different Situations • Cloud Models Give the Best Opportunity to Expand the Sample Size of Events • Flight Data With Aircraft “Truth” Provides Confirmation
Needs From Turbulence Team • Determine if Cloud Model Vertical Sigma W is properly Driving Radar Measureable Sigma U • Develop a Representative Set of Test Cases • Scoring Criteria that Accounts for Highly Variable Coupling Between Sigma W and Sigma U
Certification Tool Set • Need Aircraft “Truth” to Accompany ADWRS Test Case Flight Paths • Need Updated “Baseline” and “NESPA” Post Processing Programs as a Reference for Algorithm Development and Testing • Display Program for ADWRS “Processed Data Output” files Would Be Very Helpful • Need Fix for tass_reader to Accept Dickinson Model
Aircraft Installation Issues • How Many Aircraft Categories are needed for Aircraft Hazard Tables? (Number of Program Straps) • Error Analysis for “Weight” Input Requirement is Still TBD • Flight Deck Interface Requirements • Aural Alert • ICON • Text Visual Alert???