Synthetic Aperture Acoustic Imaging of Canonical Targets with a 2-15 kHz Linear FM Chirp
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 system's 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
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 25, 2011
- Accession Number
- ADA558467
Entities
People
- Chelsea Good
- John Judge
- Joseph Vignola
- Mehrdad Soumekh
- Peter Gugino
- Steven Bishop
Organizations
- The Catholic University of America