I spent most of my career in the sonar business.  It was always assumed that sonar can only work when both the transmitter and the receiver were in the same body of water; air to water sonar was not possible because sonar can not break the air-water interface.   Sure, there were planes that could “dip” a device into the water that would transmit and receive sonar signals, but that is still considered a water-water sonar.  Thanks to the innovative minds of Stanford University, there may now be a way to transmit and receive sonar from an airborne platform.  Who would have thought?

Stanford engineers explain that the Photoacoustic Airborne Sonar System, or PASS, fires a laser into the surface of the water, its intensity pulsed to the desired acoustic frequency, and as this laser energy is absorbed, it creates ultrasonic waves in the water that can act as effective sonar waves, bouncing off underwater objects before returning up to the surface.  “If we can use light in the air, where light travels well, and sound in the water, where sound travels well, we can get the best of both worlds”

This can be a game changer for Anti Submarine Warfare.  Aircraft would be able to search for submarines without dropping sensors into the water.  This would be advantageous because aircraft could search an area more quickly, and the splashing sound of the sensors would not give away the presence of the aircraft.

If sonar interests you, or if you work with sonar, consider taking the upcoming ATI course “Sonar Principles and ASW Analysis.”  This three-day course provides an excellent introduction to underwater sound and highlights how sonar principles are employed in ASW analyses. The course provides a solid understanding of the sonar equation and discusses in-depth propagation loss, target strength, reverberation, arrays, array gain, and detection of signals. 

To learn more about this course, and to register, you can go here.

And, to learn more about other courses offered by ATI, please go to www.aticourses.com