A Wireless Sensor Network and Communication System of an Autonomous Unmanned Vessel

Abstract

Studying the bottom of lakes using hydroacoustic methods allows to obtain valuable information about the evolution of organisms, geological structures, make bathymetric maps, and also search for various objects. However, research near the shore or in shallow water is difficult due to the fact that the research vessel must be small. One of the modern approaches is the use of robotic unmanned vessels. In such devices, the most important element is the communication system, which completely determines their functionality and flexibility. The aim of the work is to design a communication system of an unmanned vessel based on the use of modern wireless networks protocols and IoT technologies. The main systems and sensors are described in details. The use of NodeMCU microcontrollers with ESP8266 Wi-Fi modules allowed to integrate all sensors with various protocols into a flexible wireless network. A local server based on Raspberry Pi mini PC implemented quick data acquisition via MQTT protocol. The vessel is also equipped with LoRa UHF transmitter for transition of main systems’ parameters to an operator’s post if it is located farther than 2 km form the research area. Work of the robotic vessel was tested during an expedition to Lake Baikal. The paper demonstrates results of bathymetric measurements of the nearshore area nearby Baikal Gigaton Volume Detector. The field testing showed stability of automatic movement along the specified route. The minimal detected depth has been about 1 m, which makes the autonomous vessel a unique instrument for measurements including shallow water.