Airborne Sonar

Despite the crucial role oceans play in regulating climate, absorbing carbon, and sustaining biodiversity, over 80% of the ocean remains unmapped, uncharted, and unobserved by humans. This vast information gap persists largely due to the limitations of current underwater sensing technologies, which rely on slow, localized, and resource-intensive deployment methods. A paradigm shift in how we sense and image underwater environments is urgently needed—one that can make ocean exploration as scalable and accessible as satellite imagery has made land observation.

Traditional sonar systems, though capable of producing high-resolution underwater images, are fundamentally constrained by the vehicles that carry them. Ship-mounted or towed sonar arrays can only cover limited areas and are slow to deploy, preventing frequent and large-scale monitoring of marine environments. In contrast, airborne sensing modalities such as radar and lidar revolutionized terrestrial mapping by providing fast, wide-area coverage—but these technologies fail underwater due to high electromagnetic absorption losses. This technological bottleneck has left a major portion of our planet’s surface beyond the reach of modern imaging and analysis tools.

To overcome these challenges, we propose the development of a multi-modal airborne sonar system that combines the complementary strengths of light and sound to penetrate the air–water interface. Using a laser to generate acoustic waves via the photoacoustic effect, our system can transmit and receive underwater echoes from an aerial platform, enabling real-time, large-scale underwater imaging. By leveraging highly sensitive ultrasonic receivers and surface-profile correction algorithms, this approach opens the door to an entirely new sensing paradigm—one that could eventually serve as the “Google Earth of the underwater world,” transforming marine research, environmental monitoring, and exploration.

For more details, check out our project homepage and our publications listed below.

Publications

[1] A. Fitzpatrick, A. Singhvi, and A. Arbabian, “An airborne sonar system for underwater remote sensing and imaging,” IEEE Access, vol. 8, pp. 189 945-189 959, 2020.

[2] A. Fitzpatrick, R. P. Mathews, A. Singhvi, and A. Arbabian, “Multi-modal sensor fusion towards three-dimensional airborne sonar imaging in hydrodynamic conditions,” Communications Engineering, vol. 2, p. 16, 2023.

[3] A. Fitzpatrick, A. Singhvi, J. Mukania, B. Ye, E. Giebler, and A. Arbabian, “Three-Dimensional Mapping of Water Surface Waves using Air-Coupled Sonar”, 2023 MTS/IEEE OCEANS Conference, Sep 25-28, 2023.

[4] W. Meng, A. Fitzpatrick, A. Singhvi, and A. Arbabian, “Laser Scanning for Single-Shot Frequency Diverse Photoacoustic Excitation,” 2022 IEEE International Ultrasonics Symposium (IUS), Oct 10-13, 2022.

[5] A. Fitzpatrick*, A. Singhvi*, and A. Arbabian, “Dynamic Tuning of Sensitivity and Bandwidth of High-Q Transducers via Nested Phase Modulations,” 2022 IEEE International Symposium on Circuits and Systems (ISCAS), May 27- June 1, 2022.

[6] A. Singhvi, A. Fitzpatrick, and A. Arbabian, “An Electronically Tunable Multi-Frequency Air-Coupled CMUT Receiver Array with sub-100µPa Minimum Detectable Pressure Achieving a 28kb/s Wireless Uplink Across a Water-Air Interface,” Proc. 2022 IEEE Int. Solid-State Circuits Conf. (ISSCC), Feb 20-26, 2022.

[7] A. Singhvi*, M. L. Wang*, A. Fitzpatrick* and A. Arbabian, "Multi-Task Learning for Simultaneous Speed-of-Sound Mapping and Image Reconstruction Using Non-Contact Thermoacoustics," 2021 IEEE International Ultrasonics Symposium (IUS), Virtual Symposium, Sept 11-16, 2021.