2025_programme: Development of an airborne circular sonar for research and teaching

• Day: June 17, Tuesday
    Location / Time: D. CHLOE at 11:40-12:00
• Last minutes changes: -
• Session: 18. Towards Automatic Target Recognition. Detection, Classification and Modelling
  Organiser(s): Johannes Groen, Yan Pailhas, Roy Edgar Hansen, Narada Warakagoda
  Chairperson(s): Johannes Groen, Yan Pailhas
• Lecture: Development of an airborne circular sonar for research and teaching [Invited]
  Paper ID: 2217
  Author(s): Blair Bonnett, Kaushikk V. N., Sudhanshu Apte, Thomas Fickenscher
  Presenter: Blair Bonnett
  Abstract: Sonar is largely considered to be an underwater technique due to the predominance of other measurement methods for above-water applications. However, in-air echolocation is used by various animals (bats being the obvious example). It has also been utilised in some electronic sensors, for example basic range finders and fluid level sensors. Recent publications have shown that synthetic aperture sonar (SAS) images can be formed from data collected with standard audio speakers and microphones. This allows complex scenes to be imaged in a controlled laboratory environment for validating processing and analysis techniques, although differences in the acoustic response of the targets in air versus in water must be considered. Such a system can also be a valuable tool for teaching and demonstrating sonar principles.\n\nThis paper introduces an airborne circular SAS system under development. It uses a Peerless OC16SC00-04 speaker (16mm diameter) and Knowles SPG08P4HM4H-1 MEMs microphones (4mm by 2mm). An AMD Zynq system-on-chip comprising a dual-core ARM Cortex-A9 processor and AMD 7 series FPGA is used to control the system and synchronise the components. The system is operated over a standard Ethernet connection. The small size of the microphones and the ability of the FPGA to handle many microphones simultaneously (62 in the current setup) allows for receiver arrays analogous to those used by underwater systems. This creates an opportunity to implement array-based processing techniques such as interferometry or motion compensation.\n\nAs with underwater sonar, precise calibration of the system and knowledge of the environment (in particular, the speed of sound) are required to obtain good results. We show the current status of the system and its calibration along with some applications. Future development plans, including for alternative hardware designs, will be outlined. All custom hardware designs and software for using the system will be released under open source licenses. \n
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  This paper is a candidate for the "Prof. John Papadakis award for the best paper presented by a young acoustician(under 40)"
• Corresponding author: Dr Blair Bonnett
  Affiliation: Helmut Schmidt University
  Country: Germany