Multi-UUV object detection, localization and tracking with secure, full-duplex communication networks

Abstract

Proposed, is a novel OFDM/CDMA communications network that runs on full-duplex software-defined underwater acoustic modems. This system is designed to detect, localize and track mobile underwater targets using multiple collaborating unmanned underwater vehicles (UUVs). This underwater network will be presented and described as a communications system. To start, the underwater channel characteristics (shallow, multi-path and high ambient) are described. The requirement is signal propagation that is secure (encoded), spread spectrum, robust to frequency selective fading, and efficient. This requirement is not easily met by existing full-duplex communications stacks. The proposed OFDM and CDMA modulation schemes better address this on embedded systems like UUVs. Therefore, the modem’s functions are integrated into the UUV with the Robot Operating System (ROS) middleware. These acoustic modems natively run UnetStack – a stack that focuses on underwater communication networks. The ROS nodes that control the UUV communicate to/with the modem using the UnetPy’s socket API. Scenarios are demonstrated where one stationary UUV/modem and two underway ones communicate in a full-duplex configuration. In the process, messages / signals on UUV/modem location, speed, heading, etc. are securely and efficiently exchanged among UUVs/modems. Finally, the proposed system is validated through UnetStack’s hardware-in-the-loop simulations (UnetSim) and multiple in-water tank trials.