Accession Number:

ADA558467

Title:

Synthetic Aperture Acoustic Imaging of Canonical Targets with a 2-15 kHz Linear FM Chirp

Descriptive Note:

Briefing charts

Corporate Author:

CATHOLIC UNIV OF AMERICA WASHINGTON DC

Report Date:

2011-04-25

Pagination or Media Count:

46.0

Abstract:

Synthetic aperture image reconstruction applied to outdoor acoustic recordings is presented. Acoustic imaging is an alternate method having several military relevant advantages such as being immune to RF jamming, superior spatial resolution, capable of standoff side and forward-looking scanning, and relatively low cost, weight and size when compared to as compared to 0.5 - 3 GHz ground penetrating radar technologies. Synthetic aperture acoustic imaging is similar to synthetic aperture radar but more akin to synthetic aperture sonar technologies owing to the nature of longitudinal or compressive wave propagation in the surrounding acoustic medium. The systems transceiver is a quasi mono-static microphone and audio speaker pair mounted on a 5-meter rail. Received data sampling rate is 80 kHz with a 2-15 kHz Linear Frequency Modulated LFM chirp with a pulse repetition frequency PRF of 10 Hz and an inter-pulse period IPP of 50 milliseconds. Targets are positioned within the acoustic scene at slant range of two to ten meters on grass, dirt or gravel surfaces and with and without intervening metallic chain link fencing. Acoustic image reconstruction results in means for literal interpretation and quantifiable analyses. A rudimentary technique characterizes acoustic scatter at the ground surfaces. Targets within the acoustic scene are first digitally spotlighted and further processed providing frequency and aspect angle dependent signature information

Subject Categories:

  • Acoustic Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE