The Minimum Number of Ground Measurements Required for Narrow Sonic Boom Metric 90% Confidence Intervals

Open Access
Author:
Doebler, William J
Graduate Program:
Acoustics
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
October 30, 2017
Committee Members:
  • Victor Ward Sparrow, Thesis Advisor
  • David Carl Swanson, Committee Member
  • Stephen Thompson, Committee Member
Keywords:
  • sonic boom
  • SCAMP
  • NASA
  • FAA
  • ICAO
  • confidence interval
  • metric
  • certification
  • noise
  • sound
  • supersonic
  • 90% confidence interval
Abstract:
For subsonic aircraft noise certification, the value of the effective perceived noise level EPNL must be known within an adequately narrow 90% confidence interval at the ground during a takeoff, during the climb, and during the approach to landing. To do this, at least 6 ground measurements are required for each aircraft condition. It may be useful to develop a noise certification standard that parallels the subsonic certification standard. This work analyzes the number of ground measurements needed for narrow 90% confidence intervals for an aircraft in supersonic cruise flight from NASA's Superboom Caustic Analysis and Measurement Program SCAMP. Three methods of selective ground measurement removal were used to determine the minimum number of ground measurements necessary for narrow 90% confidence intervals for 5 different human-perception-correlated sonic boom metrics. For each metric, the minimum number of ground measurements necessary for a narrow confidence interval is between 7 and 10. The analysis is also able to estimate which metrics have values that change minimally due to atmospheric turbulence.