Presentation Title

Analog Front-End for Imaging with Underwater Ultrasound Phased Array

Faculty Mentor

Matthew Spencer

Start Date

23-11-2019 8:45 AM

End Date

23-11-2019 9:30 AM

Location

176

Session

poster 2

Type of Presentation

Poster

Subject Area

engineering_computer_science

Abstract

This work presents an underwater ultrasound imaging system intended for fish tracking purposes.

A two-dimensional phased array of piezoelectric transducers is used to steer a concentrated beam of ultrasound. Reflections from targets in the water are reconstructed based on the time delay between echoes returning to different elements of the transducer array. This research discusses the design of an analog front-end used to receive echoes returning from underwater objects.

Tests were conducted in a 3.6m x 3.6m x 1.5m test tank in the Harvey Mudd College Underwater Robotics Lab. The system uses a 3x3 phased array, with one transmitting power amplifier and one receiving amplifier for each piezoelectric element. Tx/Rx switches are used to protect the receiving circuitry from the high-voltage transmit signals, and oscilloscopes are used to capture the returning echoes. This work terminated in the locating of a 0.25m x 0.3m metal plate, to an accuracy within the area of the plate. The plate was positioned at various locations within a roughly 2m radius of phased array in the tank. The results were visualized by a heat-map images of the tank with the plate in it.

Current fish tracking systems have limited battery life and require multiple hydrophones on the surface of the water to trilaterate the location of a fish based on acoustic pings coming off the tracking tag. One potential application of this ultrasound power and data link is in a battery-less fish tracking system that uses a piezoelectric transducer on the tracker to harvest power from the transmitting array and then backscatter useful data. This device is also being developed by Harvey Mudd College undergraduate researchers.

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Nov 23rd, 8:45 AM Nov 23rd, 9:30 AM

Analog Front-End for Imaging with Underwater Ultrasound Phased Array

176

This work presents an underwater ultrasound imaging system intended for fish tracking purposes.

A two-dimensional phased array of piezoelectric transducers is used to steer a concentrated beam of ultrasound. Reflections from targets in the water are reconstructed based on the time delay between echoes returning to different elements of the transducer array. This research discusses the design of an analog front-end used to receive echoes returning from underwater objects.

Tests were conducted in a 3.6m x 3.6m x 1.5m test tank in the Harvey Mudd College Underwater Robotics Lab. The system uses a 3x3 phased array, with one transmitting power amplifier and one receiving amplifier for each piezoelectric element. Tx/Rx switches are used to protect the receiving circuitry from the high-voltage transmit signals, and oscilloscopes are used to capture the returning echoes. This work terminated in the locating of a 0.25m x 0.3m metal plate, to an accuracy within the area of the plate. The plate was positioned at various locations within a roughly 2m radius of phased array in the tank. The results were visualized by a heat-map images of the tank with the plate in it.

Current fish tracking systems have limited battery life and require multiple hydrophones on the surface of the water to trilaterate the location of a fish based on acoustic pings coming off the tracking tag. One potential application of this ultrasound power and data link is in a battery-less fish tracking system that uses a piezoelectric transducer on the tracker to harvest power from the transmitting array and then backscatter useful data. This device is also being developed by Harvey Mudd College undergraduate researchers.