Azimuth ambiguities in broadside and squint mode synthetic aperture sonar

Author

McHugh, R. ; Shaw, S. ; Taylor, N.

Author_Institution

Dept. of Comput. & Electr. Eng., Heriot-Watt Univ., Edinburgh, UK

Volume

146

Issue

2

fYear

1999

fDate

4/1/1999 12:00:00 AM

Firstpage

113

Lastpage

119

Abstract

Synthetic aperture sonar (SAS) mapping rates are limited by the acoustic propagation speed in relation to the feasible platform velocity and the desired swath coverage. Such limitations result in azimuth undersampling and the appearance of ambiguities in SAS imagery. The position, spreading and ambiguity to signal ratio (ASR) of image aliases caused by grating lobes are discussed from a geometric and a Doppler point of view. Simulation and experimentation for sidelooking SAS imaging show the variation in ASR with along track sampling, processed aperture, target range, and transmitted signal bandwidth. ASR is also shown to improve with increasing SAS squint angle considered up to 60° from broadside

Keywords

Doppler effect; sonar imaging; synthetic aperture sonar; underwater acoustic propagation; Doppler frequency; SAS imagery; acoustic propagation speed; along track sampling; ambiguity to signal ratio; azimuth ambiguities; azimuth undersampling; broadside mode synthetic aperture sonar; experiment; grating lobes; image aliases; mapping rates; platform velocity; position; processed aperture; sidelooking SAS imaging; simulation; spreading; squint angle; squint mode synthetic aperture sonar; swath coverage; target range; transmitted signal bandwidth;

fLanguage

English

Journal_Title

Radar, Sonar and Navigation, IEE Proceedings -

Publisher

iet

ISSN

1350-2395

Type

jour

DOI

10.1049/ip-rsn:19990260

Filename

788024