|Title||Broadband synthetic aperture geoacoustic inversion|
|Publication Type||Journal Article|
|Year of Publication||2013|
|Authors||Tan B.A, Gerstoft P, Yardim C, Hodgkiss WS|
|Journal||Journal of the Acoustical Society of America|
|Type of Article||Article|
|Keywords||field; impulse-response; receiver; shallow-water; ship noise; single hydrophone; source localization; uncertainty; underwater acoustics inversion; wave-guide|
A typical geoacoustic inversion procedure involves powerful source transmissions received on a large-aperture receiver array. A more practical approach is to use a single moving source and/or receiver in a low signal to noise ratio (SNR) setting. This paper uses single-receiver, broadband, frequency coherent matched-field inversion and exploits coherently repeated transmissions to improve estimation of the geoacoustic parameters. The long observation time creates a synthetic aperture due to relative source-receiver motion. This approach is illustrated by studying the transmission of multiple linear frequency modulated (LFM) pulses which results in a multi-tonal comb spectrum that is Doppler sensitive. To correlate well with the measured field across a receiver trajectory and to incorporate transmission from a source trajectory, waveguide Doppler and normal mode theory is applied. The method is demonstrated with low SNR, 100-900 Hz LFM pulse data from the Shallow Water 2006 experiment. (C) 2013 Acoustical Society of America.