In June 2018, the specialists of Vector Marine Electronics, Ltd and FGBNU VNIRO conducted in the framework of the ROC “Design and manufacture of import-substituting portable multi-purpose single-beam research echo sounder with a split beam”, the MIEL cipher carried out a comparative hydroacoustic survey at the Vazuzskom reservoir (measuring ground VNIRO) developed experience small-scale scientific echo sounder (MIEL) with a scientific echo sounder EY-500 of the Norwegian firm Simrad.
The need to create a domestic echo sounder for carrying out resource studies in inland waters and in shallow depths is related to the fact that foreign scientific echo sounders have narrow antenna patterns, which does not allow them to be used at depths less than 3 meters due to small volumes of water sounding and therefore, low data representativeness. In addition, the cost of such devices is not available to the vast majority of Russian scientific organizations. After the introduction of sanctions by Western countries, many foreign manufacturers have stopped selling high-tech products to our country, and those that can be supplied are practically deprived of technical support, as many representative offices in Russia were closed, and the development of any high-tech products implies close cooperation between the developer and the user. . By purchasing foreign equipment, our users are deprived of contact with Western manufacturers and the possibility of upgrading and improving the acquired equipment. Over the past decades, in the Russian Federation, not a single domestic fishing or scientific echo sounder was created; therefore, in 2017, a national echo sounder was created with a wide directivity pattern and a split beam under the code 0004. After testing this device, a number of comments were made to its software ( BY). Based on the refinement of the echo sounder software and the upgrade of the antenna case, a new model appeared under the name MIEL (small-sized research echo sounder). The figure shows a photograph of this echo sounder consisting of a wideband antenna with a split beam, an electronic unit and a cable.
The aim of the work was to conduct hydroacoustic surveys in the water area of the Vazuzsky reservoir while simultaneously using two echo sounders: the Norwegian EY-500 with the antenna ES-70-11 (split beam, beam width 11 degrees, filling frequency of 70 kHz pulses) beam width 20 degrees, the frequency of filling pulses of the parcel 200 kHz) for further comparison of the processing results. The Norwegian Simrad EY-500 echo sounder was used as a reference instrument. The figure shows the EY-500 echo sounder consisting of a split beam antenna, an electronic unit, a connecting cable and a computer.
The echo sounders in the process of shooting were connected to GPS systems with the aim of linking the measurement results to the location on the map. For the installation of two antennas on the rod for simultaneous shooting a special design was developed and manufactured by the laboratory from stainless steel.
The distance between the antennas was 15 cm, which made it possible to record the same clusters and single fish during the survey. The survey was performed on a pre-planned parallel grid of tacks. The equipment was installed on a Voronezh-K boat equipped with a 9.9 hp Yamaha engine. Antennas were placed on the right side of the vessel. The speed of the vessel during the shooting was 5-6 km / h. In the course of the work, no interference was observed on the echo sounder screen from the engine. On the echo sounders were installed the same borehole parcels and their duration (0.6 msec). The time and start of recording on echo sounders was synchronized.
According to the preliminary results of the analysis of the recorded echogram, it can be unambiguously said about the complete coincidence of the number of objects recorded by the MIEL and EY-500 echo sounders. The difference in the geometry of the recorded targets is explained by the different widths of the antenna patterns, and some color differences between the recorded objects and the bottom are different frequencies of filling the pulses of the parcel. In the future, using the postprocessing processing system, it is planned to calculate average values of target strength, fish length and surface density of fish concentrations in specimen / ha on each tack of the survey, as well as build fish size distribution tablets in the surveyed water area and compare the calculation results.
Information about the hydroacoustic surveys conducted was reported at the colloquium of the field hydroacoustics laboratory held at VNIRO.