Experimental Complex for Studying the Possibilities of Using Hydroacoustic Sensors in Underwater Vision Systems

Abstract

A description of a laboratory experimental and measuring complex is given, including a linear aquatic environment in the form of an extended cylindrical reservoir (hydro wave) and an experimental pool equipped with a system for generating test hydroacoustic signals, a set of electroacoustic and acoustoelectric transducers, and a system for amplifying and digitizing received signals. The results of experimental studies of hydroacoustic piezoelectric sensors and the features of the propagation of the waves generated by them in the described laboratory complex are presented. These results include: an assessment of the sensitivity of sensors, an assessment of the frequency characteristics of sensors, a study of the frequency response of a system of two sensors fixed at the ends of a horizontal hydro-wave guide, a comparison of the results of measurements of the frequency response of sensors in a pipe and a pool, a comparison of signal pulling over time in a pipe and a pool, a study of operation sensors in sonar mode. The most significant results illustrating the behavior of hydroacoustic signals and the potential of the measuring complex are the established possibilities for determining the resonance features of electroacoustic transducers and the detail of the characteristics of the reflection of acoustic signals from objects in an aquatic environment. The main investigated characteristics of hydroacoustic sensors are the sensitivity and frequency characteristics of the investigated sensors, the amplitude-frequency characteristics of the system from the transmitting and receiving transducers, and the features of the transducers' operation in the sonar mode. According to the research results, the characteristics of the sensitivity of the sensors and the assessment of the spread of the sensitivity indicators for representatives of the same type of different parties were obtained. The study of the frequency characteristics of the sensors was focused on the study of the dependence of the module and the phase of the sensor resistance on the frequency and on the determination of the resonance characteristics of the sensors. The presence of resonances (resistance minima) and antiresonances (resistance maxima) in several frequency regions was established. When examining the transducers in sonar mode, a glare structure of echo signals from the components of a complex object (a sphere suspended by a thread), separated by time intervals of 12.3 microseconds, was clearly observed. The delay of the signal reflected from the filament in relation to the signal reflected from the front wall of the sphere is due to the distance by two radii of the sphere, covered by the signal reflected from the filament. Carrying out research in two experimental situations (linear hydro wave and experimental pool) allows assessing the degree of adequacy of the results obtained in the sense of comparing similar experiments in different conditions.