Team 16 - Modem Integration onto Wave Glider USV

University of California, San Diego

Mechanical and Aerospace Engineering 

MAE 156B: Senior Design Project

Kai Saucedo, Thomas Dolby, Adem Evecek, Bryan Garcia, Omar Salas

NIWC Pacific

Background

The Wave Glider is an unmanned surface vehicle (USV) produced by Liquid Robotics Incorporated (LRI) and used at Naval Information Warfare Center (NIWC) Pacific for various applications. Many use cases involve equipping the Wave Glider with sensing and communication payloads.

• The Persistent Unmanned Multistatic Sonar (PUMS) system uses the Wave Glider as a host for sonar packages:

  • One acts as a source (TX), transmitting acoustic energy via a vertical transducer array.

  • Another acts as a receiver (RX), detecting and processing echoes from objects underwater.

• NIWC Pacific aims to implement a multi-modal RF, Optical, Acoustic (ROAM) Modem onto their existing Wave Glider.

• The ROAM system will act as a receiver for other submersible communication systems.

• A winch system enables the glider to lower equipment to depths up to 150 meters, connecting to a tow cable and acoustics array.

• This configuration allows modular pressure vessels (PV) to be attached for various applications.

Description of Design Solution

The pressure vessel is mounted between the S-Tow Cable and the Towed Array.

• Components and Materials

  • Stock pressure vessel housing, end caps, and locking flanges purchased from Blue Robotics (anodized aluminum).

  • FDM printed internal mountings designed to house electronics (ASA).

  • FDM printed hydrodynamic end cap cover attached to the PV’s top side (S-Tow Cable side) (ASA - Carbon Fiber).

  • Transducer mounts designed for the bottom side (towed array side).

  • Machining drawings for end caps, external connectors, and the pressure relief gauge.

Project Overview

After completing our Preliminary Design Review, the two transducers were introduced to our project, requiring us to design mountings for them on the bottom side of the PV. The prototype including our external housing unit, pressure relief gauge, and end caps were subject to preliminary tests to ensure we were meeting pressure and water-sealant standards. Upon this completion, we entered our final phase where we made final modifications as needed and completed final quality verifications before hardware hand-off. As for the hydrodynamics of the PV assembly, calculations were performed to show reductions made to the drag.

LINK TO EXECUTIVE SUMMARY: 

Summary of Performance Results:

The Acoustic Modem Integration onto Wave Glider USV successfully developed a modular and hydrodynamically optimized pressure vessel (PV) to improve underwater communication. Constructed from anodized aluminum with 7075-T6 end caps, the PV features an FDM printed ASA-CF plastic dome that reduces drag by 81% at speeds of 1.4 - 3.7 km/h. Extensive hydrostatic testing per ISO 21173 & ASME BPVC V validated the PV’s integrity at depths beyond 350 meters, with FEA confirming a factor of safety (FS) of 3 at 1000m depth. CFD simulations demonstrated the dome’s drag-reducing effects, while sealing tests ensured reliable waterproofing. These enhancements improve signal transmission, reduce operational costs, and provide a scalable solution for autonomous naval applications.