The primary consumer of the power supply system of an autonomous unmanned underwater vehicle (AUV) is its main propulsion system. To increase the efficiency of the AUV, it is crucial to reduce the electrical power consumption required to move at the desired speed. This paper presents a calculation-experimental methodology for designing a highly efficient propulsion and steering system (PPS) for the AUV. The AUV MMT-3500, developed by IMTP FEB RAS, was selected as the research object, and a new propeller was designed for its PPS to minimize the power consumption of the propulsion electric drive. During the virtual flow simulation of the 3D model of the vehicle, its hydrodynamic resistance was determined, as well as the thrust requirements for each PPS. Based on load tests of the propulsion electric drive, the control code and rotational speed were selected to provide the required shaft power with maximum efficiency. A hydrodynamic calculation of the propeller was conducted using the identified rotational speed and shaft power values, employing model test diagrams for the B-series propellers and the regression base of the Daidola & Johnson propeller optimization program. A 3D model of the propeller was developed and verified using the CAD software Solid Works 2020 with the Flow Simulation package. Pool tests of the PPS with the developed propeller in mooring mode confirmed the correctness of the technical decisions made.

The article presents a methodology for determining the main parameters of the marching propulsions of the command autonomous underwater vehicle (AUV) of the operational noise field control complex. The technique is based on the results of virtual purging of a 3D model of the vehicle with angles of attack that compensate for residual buoyancy at cruising speed. A hydrodynamic calculation of its propeller was carried out, taking into account the results of load tests of the selected electric thruster drive in accordance with the required thrust of the main propellers. An assessment of the required energy consumption of its battery is given, which ensures the necessary autonomy of using the device for its intended purpose. The dependence of the range of the device on the speed of moving has been revealed, and the presence of an extreme of this dependence has been determined.

The efficiency of autonomous unmanned underwater vehicles (AUVs) is determined by the maximum range of their movement when performing a route task, which depends on the energy capacity of the power source, the speed of travel, the hydrodynamic resistance of the vehicle, and the energy consumption of the propulsion system. The methodology is based on the results of virtual testing of the 3D model of the AUV developed by IMTP, on the basis of which the requirements for the thrust of the cruise thrusters (CT) for a given range of movement speeds were determined. In accordance with the action curves of the propeller (P) of a constant pitch, the dependence of its rotation frequency and the required power on the shaft on the speed of movement of the apparatus was calculated. In accordance with the results of load tests of the electric drive (ED) of the CT, using the interpolation algorithm, the consumed power was found, ensuring the rotation of the main propulsion unit with the required frequency. Using the regression analysis of the results of calculating this power, an analytical dependence of the power consumption of the propulsion unit of the apparatus on the speed of its movement relative to the water was determined. The proposed calculation method allows us to determine the dependence of the autonomy parameters of the apparatus (power reserve, continuous running time, required energy capacity of the onboard source) on its speed of movement, taking into account the variation in the efficiency of the main engine and the main engine. As a result of the analysis of the dependence of the cruising range on the cruising speed, its extremum was identified, corresponding to the speed of movement, providing the maximum power reserve.

В работе рассмотрены научные и технические перспективы и возможные направления развития субтерагерцовой астрономии в Российской Федерации. Предложена концепция создания субтерагерцовых инструментов в виде универсальной компактной антенной решетки для размещения на территории России. На базе концепции такой антенной решетки возможна реализация нескольких космических проектов субтерагерцового диапазона нового поколения – космического интерферометра и телескопа, расположенного на поверхности Луны. Наземные антенные решетки смогут выступить в качестве поддержки режима интерферометра со сверхдлинной базой обсерватории «Миллиметрон».

This paper addresses the scientific and technical prospects and potential directions for the development of subterahertz astronomy in the Russian Federation. The concept of creating subterahertz instruments in the form of a universal compact antenna array for placement on the territory of the Russian Federation is proposed. It is possible to implement several space projects in the subterahertz range using such an antenna array, including a space interferometer and a telescope on the surface of the Moon. Ground-based compact antenna arrays will be able to act as a support for the very long baseline interferometer mode of the Millimetron observatory.

The efficiency of using uninhabited underwater vehicles of the tethered type is associated with the need for its propulsion and steering complex (PSC) to compensate for the reaction of the communication cable of the device with the support vessel when maneuvering near the work site. The work examines the achievable boundaries of the maneuvering zone of a remotely controlled uninhabited underwater vehicle (ROV) for known values of the length of the communication cable, the submersion depth of the device, the current speed in the work area and the traction characteristics of the PSC. Algorithms for determining the boundaries of the working area and the achievable speed of the apparatus are presented, based on calculating the tension at the ends of the communication cable in a stationary flow, using the equations of a catenary line and the numerical integration of the equations of an inextensible flexible thread. In order to increase the operational reliability of underwater technical work, recommendations have been developed for choosing a cable length that prevents it from sagging below the submersion depth of the apparatus with possible snagging and damage by bottom objects. During the model experiment, the boundaries of the maneuvering zone were assessed relative to the coordinates of the carrier for a promising ROV with known hydrodynamic resistance and traction characteristics of the PSC, as well as the dependence of the achievable speeds of the vehicle within the maneuvering zone on the immersion depth and the speed of the oncoming current.

The efficiency of underwater technical operations by remotely operated unmanned underwater vehicles (ROV) equipped with a multi-link manipulator (MM) is largely determined by the accuracy of the ROV dynamic positioning above the work object under conditions of disturbing effects from the current and the communication cable with the support vessel. The report proposes a new approach to the development of a mathematical model of the ROV motion control system (MCS), taking into account the force effects of the communication cable caused by the underwater current and the motion of the vehicle itself. The proposed mathematical model of the cable response to the vehicle is based on pre-calculated values of the running end tension in a steady oncoming flow within a certain maneuvering area of the ROV. The hydrodynamic characteristics of the promising ROV were determined as a result of virtual blowing of its 3D model, and the mathematical model of the propulsion and steering complex (PSC) was developed in accordance with the used layout scheme and the results of mooring tests of the used propeller. The modeling of the ROV motion was carried out taking into account the influence of cable tension along one of the typical trajectories. The developed mathematical model of the ROV control system allows for more accurate determination of the requirements for the propulsion and power supply system (PSS) of the device at the preliminary design stage. In addition, this model can be used as an element of supporting the operator's activities for the optimal deployment of the underwater tethered system “vessel - communication cable - ROV”.

The use of support vessels significantly increases the cost of monitoring objects of underwater production complexes (UPC), and the presence of a cable communication line significantly limits the possibility of using remote-controlled uninhabited underwater vehicles (ROV), which is reduced to zero in conditions of continuous ice coverage of the work area. An obvious alternative to the use of ROVs are autonomous uninhabited underwater vehicles (AUVs), equipped with equipment for conducting contact work with monitoring objects and communicating with the shore control post. At the same time, the necessary autonomy for the use of such hybrid autonomous uninhabited underwater vehicles (HAUVs) can be ensured by a network of bottom stations equipped with systems for contactless charging and information exchange with the shore UPC control post. The work proposes the concept of an underwater service station (USS) for a HAUV, which allows, in long-term underwater deployment conditions, to use the device not only in an autonomous mode, but also in a remote control mode from a shore control post. A model for using the station for its intended purpose and the composition of the equipment necessary for its implementation have been determined, the design of the technical solution of the station has been presented, determined taking into account the features of installation on a complex bottom surface and the requirements for docking the HAUV for contactless charging and information exchange, including in the mode of remote control from the SCP. Basic technical solutions for the USS have been developed that provide automatic adjustment of the horizontal position of the docking unit, reliable docking and holding of the HAUV charging and information exchange terminals, and control of the vehicle’s pointing process using a set of rotary video cameras with lamps and a sector-view sonar. Algorithms for interaction between the station and the HAUV have been developed for autonomous and controlled via optical communication cable operating modes of the vehicle.

The problems of controlling the movement of a hybrid autonomous unmanned underwater vehicle (HAUV) during operational monitoring of the noise field in the sea are considered. To organize the movement of the HAUV, which consists of several stages, a control complex is used that ensures the fulfillment of the specified requirements for the dynamics of the vehicle and for the conditions for effective measurements of noise field parameters using a scalar-vector receiving system. The structure and mathematical models of the propulsion-steering complex, buoyancy and moment of stability control systems are studied. Optimization of the operation of the HAUV in the acoustic station mode was carried out by model and experimental adjustment of the parameters of these systems, taking into account the specific features of their design. When analyzing its structure and dynamic properties, the MMT-300-M AUV was adopted as a prototype of the HAUV. The results of a computational experiment on the hydrodynamics of the vehicle based on the virtual purging of its three-dimensional model are presented, as well as the results of modeling the dynamics of the vehicle when operating in the acoustic station mode.

The efficiency of using tethered underwater vehicles is determined by the ability of the propulsion and steering complex (DRC) to compensate for the reaction of the communication cable of the vehicle with the support vessel when maneuvering near the work site. The paper considers an assessment of the achievable boundaries of the ROV maneuvering zone for given values of the length of the communication cable, the depth of the submersion of the vehicle, the current velocity in the area of work and the traction characteristics of the ROV. An algorithm for calculating the tension of the ends of the “device - carrier” communication cable in a stationary flow, based on the numerical integration of the equations of an inextensible flexible thread, is presented. Recommendations have been developed for choosing a cable length that excludes its sagging below the ROV immersion depth with possible hooking and damage to bottom objects. On the example of a promising ROV the boundaries of the maneuvering zone were evaluated relative to the coordinates of the carrier, as well as the dependence of the achievable speeds, jointly with the supporting vessel, on the depth of immersion.

Development of technologies for bottom-based submersibles is a modern and promising solution for servicing robotic systems for monitoring underwater oil production facilities and other long-term inspection work. The paper proposes the concept of an underwater support station for underwater vehicles and considers its main components in more detail. The constructive appearance of the proposed technical solution is presented.

H2O MegaMaser emission may arise from thin gas discs surrounding the massive nuclei of galaxies such as NGC 4258, but the physical conditions responsible for the amplified emission are unclear. A detailed view of these regions is possible using the very high angular resolution afforded by space very long baseline interferometry (SVLBI). Here we report SVLBI experiments conducted using the orbiting RadioAstron Observatory that have resulted in detections of the H2O 22 GHz emission in NGC 4258, with Earth–space baselines of 1.3, 9.5 and 19.5 Earth diameters. Observations at the highest angular resolutions of 11 and 23 μas show distinct and regularly spaced regions within the rotating disc, at an orbital radius of about 0.126 pc. These observations at three subsequent epochs also indicate a time evolution of the emission features, with a sudden rise in amplitude followed by a slow decay. The formation of these emission regions, their regular spacing and their time-dependent behaviour appear consistent with the occurrence of a periodic magneto-rotational instability in the disc. This type of shear-driven instability within the differentially rotating disc has been suggested to be the mechanism governing the radial momentum transfer and viscosity within a mass-accreting disc. The connection of the H2O MegaMaser activity with the magneto-rotational instability activity would make it an indicator of the mass-accretion rate in the nuclear disc of the host galaxy. Harnessing the resolving power of space very long baseline interferometry results in a link between 22 GHz H2O MegaMaser emission and accretion activity in the thin disc around the nucleus of galaxy NGC 4258. The emission regions appear consistent with a periodic magneto-rotational instability in the disc.

The MT-3500 autonomous uninhabited underwater vehicle (AUV) was created at IMTP FEB RAS for deep-sea research in the Antarctic in connection with participation in the AMK-87 complex expedition in 2022. The functionality of the AUV allows it to be used also for solving other scientific and applied problems. The dynamic characteristics of the AUV determine the degree of its effectiveness in performing sonar, geophysical and hydrographic measurements in the observed marine areas. The dynamic characteristics of the AUV are studied on the basis of model and experimental data, the data are compared to refine the parameters of the hydrodynamic model and to optimize the algorithms and control parameters. The control is carried out with the help of a propulsion-steering complex, the measurements of which are obtained as a result of detailed pool and test site measurements with the propulsion characteristics of the propulsors. To analyze the dynamic processes of the developed simulation model, the experimental data of the work are used.

The article considers to development and integration of a multilink manipulator to AUV “MMT-3500” developed by Institute of Marine Technology Problems FEB RAS (Vladivostok, Russia). The manipulator is designed for collecting samples of marine organisms and bottom soil by the vehicle hovering over the object of the interests.A kinematic layout of the manipulator is proposed in the article. The layout provides control of the manipulator end-effector with given coordinates inside a working area of a computer vision system.The design overview and software control scheme of the manipulator are described in the article. The design overview of manipulator arms and it’s effectors are described and presented.

The method of increasing the reliability of data transmission under conditions of lognormal amplitude fluctuations of millimeter radio waves at the “spacecraft - ground tracking station” communication line is considered. The complexing mode of intermittent radiation with diversity coherent signals reception when combining the diversity branches according to the select diversity reception algorithm is realized. Accordingly, the estimation of optimal threshold level of the transmitting device is made. Also it is shown that for optimal threshold level, not only the minimum probability of erroneous data reception is provided, but the transmitter energy consumption is also reduced. At the same time, the nose immunity of complexing mode gain grows with an increase of dispersion of lognormal amplitude fluctuations. In this mode the transmitter power does not change. This condition provides a minimum probability of error data reception at the optimal threshold level. Besides, the fixed transmitter power maintains high reliability of all transmitting equipment, as it excludes additional tuning of the power amplifier. In this mode the transmitter power does not change. This condition provides a minimum probability of error data reception at the optimal threshold level. Besides, the fixed transmitter power maintains high reliability of all transmitting equipment, as it excludes additional tuning of the power amplifier.