0 Introduction

In recent years, with the development of marine engineering technology, underwater unmanned vehicles (UUVs) have played an increasingly important role in safeguarding national maritime rights and interests and marine security due to their flexibility, low risk, and multi-functionality [1-3]. When UUVs perform a series of tasks such as target search, tracking, parameter estimation, and maneuvering, they generally require active sonar systems to provide accurate target parameters such as range, bearing, and velocity [4-5]. Therefore, during the development of UUVs, active sonar systems need to be debugged through pool tests and actual sea trials to ensure their reliable performance. Active sonar systems typically use bare-metal or real-time operating systems, making it inconvenient to visually plot, view, and analyze the collected sonar data and signal processing results. For testing UUV active sonar systems, program updates generally need to be completed without compromising the watertight integrity. However, traditional Joint Test Action Group (JTAG) interface update methods require opening the device and involve complex wiring, making them no longer suitable [6-7]. Therefore, developing a data acquisition system adapted to the operational requirements of UUV active sonar that can completely and accurately store and transmit collected data to the host computer, and developing an online update system suitable for the special operating environment of UUVs, is of great significance. This allows for accurate assessment of the active sonar system's current operating status, subsequent performance optimization and improvement of the active sonar, accelerating the equipment debugging process, and reducing development costs.

Currently, for the development of sonar data acquisition systems, microprocessors or microcontrollers, Field Programmable Gate Arrays (FPGAs), or Digital Signal Processors (DSPs) are generally chosen as the main control chips. Wang Min et al. [8] used a DSP running the VxWorks operating system to implement a Transmission Control Protocol/Internet Protocol (TCP/IP) network protocol stack, which can transmit collected sonar data and computation results back to a computer in real-time. Zhang Yanpin [9] designed an underwater acoustic signal acquisition and processing platform based on the OMAP-L138 chip, which achieved continuous acquisition, processing, storage, and transmission of underwater acoustic signals. It also implemented the upload function for underwater acoustic data stored on a secure digital card via the LwIP protocol stack. Rong Zhiyuan [10] combined the high-speed parallel processing capability of FPGAs with the flexible process control capability of ARM to design an FPGA+ARM-based sonar data acquisition and transmission system, meeting the requirements for high precision