An Investigation into Backscattered Cross Section Calibration of an Acoustic Sounder Used for Analysis of Lower Atmospheric Turbulence
Abstract
Atmospheric temperature structure fluctuations quantified by (C sub T) squared degrade the spatial and temporal coherence of electromagnetic and acoustic waves propagating in the atmosphere. A computer controlled atmospheric echosounder measures a time averaged (C sub T) squared profile of the lower atmosphere. Assigning the proper (C sub T) squared values to the backscattered return signals depends on an accurate calibration of this instrument. Calibration involves determination of the product of the echosounder's transmission efficiency Et and reception efficiency Er. This thesis provides a preliminary investigation of a calibration process using pulsed acoustic energy backscattered from hard spheres. Supporting software calculates the desired product (E sub r)(E sub t) based on an assumption of echosounder efficiency reciprocity. Results of the calibration process investigation indicate this assumption may be invalid. The results also indicate the software performs as intended and that the proposed calibration method possesses sufficient merit to warrant further development. Keywords: Theses, Atmospheric sounding, Acoustic echosounders, Backscattered calibration, Differential scattering cross section, Backscattered cross section, Continued fraction.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1988
- Accession Number
- ADA204854
Entities
People
- David P. Davison Jr.
Organizations
- Naval Postgraduate School