A Real-Time Error-Compensated Multi-Sensor Acquisition System for Marine Geotechnical Investigation

Abstract

This article proposes a real-time error-compensated multi-sensor acquisition system for a self-weight multi-physics cone penetration apparatus that performs marine geotechnical investigation. Conventional methods such as Standard Penetration Test (SPT) and Cone Penetration Test (CPT) provide reliable high-resolution data but require dedicated offshore vessels, which are expensive to operate. To address these limitations, the apparatus with the proposed acquisition system has been developed for a lightweight and cost-effective solution. The proposed acquisition system drives hydro-compensated dual pressure transducers, strain gauges with Wheatstone bridges, and an inertial measurement unit (IMU) to obtain accurate geotechnical parameters as well as determine soil strength and stiffness properties during dynamic penetration. Additionally, the acquisition system uses an RS-485 communication protocol to transmit data over long distances up to 1.2 km at a data rate up to 100 kbps. A 10.7 V lithium-ion (Li-ion) battery powers the proposed system, generating supply voltages of 9 V, 5 V, and 2 V through on-board voltage regulators to drive analog and digital subsystems. The proposed apparatus was verified to acquire reliable geotechnical parameters through field tests, providing a viable solution for offshore wind power development and submarine cable installations.