RU2371738C1 - Hydroacoustic navigation system - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: hydroacoustic navigation system comprises a navigation base from M hydroacostic transponders with various frequencies of response and hydroacoustic transceiver arranged on object of navigation, which is used to measure time intervals of signals distribution with their further transformation into distances between underwater object and hydroacoustic transponders. Receiving hydroacoustic antenna consists of four hydrophones, each section of antenna consists of two single-channel and single multi-channel modules installed on linear bearing bracket, which is made as perforated, antennas of receivers are arranged in the form of spherical surface and are arranged on steel plate, at least one of M hydroacoustic transponders is installed on water surface.

EFFECT: improved reliability in provision of underwater objects navigation.

6 dwg

Description

The invention relates to the field of navigation, and more particularly to determining the coordinates of mainly underwater vehicles.

Known sonar synchronous rangefinder navigation system [1], containing a bottom navigation base of M hydroacoustic transponders with different response frequencies and located on the navigation object hydroacoustic transmitter, clock generator, M-channel receiver, M meters of propagation time of hydroacoustic signals to transponders and vice versa, M · N blocks for converting time intervals to distances of N in each of the channels from M, M blocks for selecting the maximum distance from N values and a coordinate calculator of the navigation object, in which, according to the number of beam paths, N-1 additional measuring instruments for the propagation time of hydroacoustic signals, N-1 delay multivibrators, N-1 strobe multivibrators, N-1 selectors are introduced into each of the M channels, and the first inputs of the N-1 propagation meters are connected to the output of the clock generator, the second inputs are connected to the first outputs of the corresponding selectors, and the outputs are connected to the M · N inputs of the time interval to distance conversion unit , the first input of each of the selectors is connected to the output of the corresponding strobe pulse multivibrator, the second input is connected to the output of the corresponding receiver channel, the input of the first delay multivibrator is connected to the output of the corresponding receiver channel, and the output of each subsequent delay multivibrator is connected to the second output of the corresponding selector, in each from M channels N (N-1), additional blocks for converting time intervals into distances, N-1 additional blocks for selecting the maximum value of dist an antenna and a distance averager, the inputs of each of the N-1 sets of N blocks for converting time intervals to distances are connected to the corresponding outputs of N-1 additional time interval meters, and the outputs are connected to the inputs of N-1 additional blocks for selecting the maximum value, the outputs of all blocks the choice of the maximum distance values are connected to N inputs of the distance averager, and the output of the distance averager is connected to the input of the coordinate calculator of the navigation object.

The navigation base of such systems, pre-installed at the bottom of the water area, as a rule, consists of 12-16 beacon transponders and is pre-calibrated in relative and geographical coordinates (relative and absolute calibrations) using a support vessel equipped with an on-board complex of satellite and sonar navigation systems. After developing their energy resource, the transponder beacons are replaced, and a new calibration of the bottom navigation base is performed. These systems make it possible to ensure the geographic location of the underwater vehicle within an area of up to 100 square kilometers and a length of up to 50 kilometers.

The use of such systems for the navigation of underwater vehicles requires a significant amount of ship time, a large number of bottom lighthouse transponders with a long battery life, and limits the range of the underwater vehicle to the communication range with the bottom navigation base.

When conducting research work using autonomous underwater manned vehicles, performing operational and tactical tasks by underwater vehicles at sea ranges of up to thousands of kilometers and an area of tens of thousands of square kilometers, operational highly reliable provision of these works without the use of a support vessel is of particular importance. A well-known system consisting of placed bottom beacon responders to ensure subsequent geographic location of the underwater vehicle has significant limitations both in terms of the range of the landfill and the complexity of performing calibration work and work related to the placement and installation of bottom stations with each replacement of power sources, having a limited life. The objective of this technical proposal is to increase reliability while ensuring the navigation of underwater objects with a simultaneous expansion of functionality.

The problem is solved due to the fact that in a hydroacoustic navigation system containing a navigation base of M hydroacoustic transponders with different response frequencies and a hydroacoustic transceiver located on the navigation object, the time intervals of signal propagation with their subsequent conversion in the distance between the underwater object and hydroacoustic are measured transponders; the receiving hydroacoustic antenna consists of four hydrophones, each section of the antenna consists of two single-channel and one multi-channel module mounted on a linear support bracket made perforated, the receiver antennas are made in the form of a spherical surface and placed on a steel plate, at least one of M hydroacoustic transponders mounted on a water surface.

The essence of the proposed method is illustrated by drawings.

Figure 1. The navigation base formation diagram, which shows underwater soil, water surface 2, bottom sonar transponders 3, drifting transponder 4 on surface 2, equipped with a satellite communication module 6 and sonar transponder 5, underwater object 7, satellites 8 of the low-orbit satellite navigation system, satellites 9 of the medium orbital satellite navigation systems.

Figure 2. The position surface of the underwater object in the sonar navigation system with an ultrashort base, which shows the receivers 10, 11, 12, 13, underwater object 7 or the bottom sonar transponder 3.

Figure 3. The relative position of the receivers of the antenna section, where the sections 14, 15, 16, 17 indicate the antenna section.

Figure 4. Functional diagram of the reception signal "on", which includes a beamforming characteristic (PHN) 18, a broadband filter 19 with correction of the amplitude-frequency characteristics, a limiter 20, a narrow-band filter 21, a detector 22, an integrator 23, a threshold circuit 24.

Figure 5. Functional diagram of signal processing, which includes a broadband filter 25 with correction of the amplitude-frequency characteristic, a limiter 26, a narrow-band filter 27, a detector 28, an integrator 29, a narrow-band filter 30, a detector 31, an integrator 32, a threshold circuit 33, a maximum selection circuit 34.

6. A satellite communications module, which includes an encoder 35, a device for generating 36 transmission packets of messages, a device for generating 37 message packet transmission algorithms, a control device 38 with a transmitter program for emitting radiation (3-8 times / day), an antenna 33 of an omnidirectional type.

The drifting transponder 4 is a device consisting of a polyurethane housing, on which a mast is installed with a satellite antenna placed on it and, if necessary, meteorological sensors. Inside the case, equipment for measuring, processing and storing information is installed.

When installing a large group of drifting stations, communications equipment may also include a repeater that receives the radio signal from the drifting station in the UHF band (401-403 MHz), combines with the signals of other drifting stations into a common group signal, and simultaneously transmits to ground receiving points in two trunks SMV band (4/6, 7/8 GHz), and if necessary, the communications equipment may include a coastal satellite communication station that receives the emitted group signal of the repeater and contains the device a message recovery tour including a decoder and a message processing and recovery device, a storage device, a control device.

Message processing includes error-correcting coding, breaking each message into packets with a duration depending on the state of the excited surface, transmitting message packets to the relay according to an algorithm automatically generated depending on sea waves, which is determined by the satellite navigation system in accordance with known algorithms (see , for example, the description of the patent of the Russian Federation No. 2254600).

The use of drifting transponders installed on drifters equipped with a GPS receiver and equipment for a hydroacoustic communication channel as navigation beacons located on the sea surface in combination with bottom transponders allows for high-precision navigation for underwater objects.

Obviously, the location of the navigation drift beacon on the sea surface does not require relative and absolute calibration of the landfill, which is necessary when using bottom sonar transponder beacons, since the drifter's GPS receiver allows it to “know” its geographical coordinates in real time with high accuracy (for example, the accuracy of determining coordinates using a satellite navigation measuring module of the SNIM type developed by the Russian company Navis is no worse than 5 meters s). At the same time, upon request, receive signals from the bottom transponders to clarify their coordinates, which are subject to displacement from the original installation sites under the influence of factors caused by the influence of underwater currents and lithodynamic processes. Navigation of the underwater object relative to the bottom transponders and the drifting station or base from the drifting stations can be carried out both in the mode with a long, ultrashort base (DB and UKB), and in the combined DB / UKB mode.

The underwater object is equipped with hydroacoustic transmitting and receiving antennas corresponding to the operating mode, a navigation controller, and navigation mathematical software.

The drifter beacon operates in the request-response mode and in the pinger mode (beacon). In the long-base mode, to determine the coordinates of the underwater object, signals from at least 3-4 drifting beacons are used (similar to satellite GPS) and the triangulation problem is solved. In this case, the area or extent of the system coverage area depends on the energy range of hydroacoustic communication, the number of drifters, the depth of the underwater object, hydrology, noise of the underwater object and the sea surface. At the same time, unlike navigation using only the bottom navigation base, joint navigation with the help of lighthouse drifters and bottom transponders significantly expands the functionality of the underwater object, makes it possible to quickly equip a working range of any area and length with the required number of drifters, and allows the underwater object to determine its coordinates in real time, quickly change your tactical tasks without losing navigation information, receive data on your co To residents at any necessary time or constantly in an automatic mode.

When navigating an underwater object while operating at depths of more than one kilometer, it is advisable to work at frequencies in the range from 8 to 15 kHz, while the energy range of communication with the drifting beacon will reach 10-14 km, and the error in determining the coordinates of the device will be 7-10 meters in DB mode and 0.3% of the range in the UKB mode and 0.5 degrees, according to the direction finding angle. At a working depth of less than one kilometer, it is advisable to use operating frequencies in the range of 25-35 kHz and work in the UHF mode. In this case, the maximum communication range will reach about 3 km.

Moreover, each signal of the drifting beacon has a special format and encoding and carries information about the geographical coordinates of the drifting beacon and bottom transponders, its individual number, direction and speed of its movement on the surface relative to bottom transponders. The algorithm of the navigation system using drifters has a flexible structure and can be easily adapted both to a pre-laid route of an underwater object at the landfill, and to determine the coordinates of an underwater object at any specific time of its operation at the landfill in various hydrological conditions, noise conditions, including including subject to the conditions of protection against detection.

The underwater object records the distance and bearing to the drift lighthouse (UKB mode) and calculates its exact geographical coordinates using information received from the drift lighthouse via the sonar communication channel. The sonar transmission rate may be 9600-12400 baud. The most optimal communication range in the UKB mode, with an underwater object depth of up to 500 meters - 1 km. Accuracy of determination of coordinates to 5 meters.

The presence of a hydroacoustic communication channel between the drifter, bottom transponders and the underwater object also allows the transmission of service information from the ground Center to the underwater object via a satellite telemetric communication channel through a drift station located in the area of hydroacoustic communication with the underwater object.

In the proposed device, which is a sonar navigation system, a combined sonar navigation system with a long and ultrashort base is used, which allows you to use the direction finding system to solve the problem of the underwater object reaching the installation point of a drifting station or bottom transponder. At the same time, the hydroacoustic antenna of the bottom transponders, as well as the underwater object, represents two bases with receivers that have a common center. Moreover, if two receiving bases are located in a plane parallel to the deck plane and are orthogonal, the axis of one base is directed along the axial line of the underwater object, and the axis of the other base is directed to the right along the beam.

Two having a common center base of receivers allow you to determine the direction to the signal source as the line of intersection of two conical surfaces with matching vertices. The phase shift Δφ _{1 of the} electrical signals of two point receivers (first second) arriving at the inputs of the receiving path is related to the angle between the base line and the direction of arrival of the signal by the ratio

Δφ ₁ = kcosα, where α is the angle of arrival of the signal, k is a coefficient equal to k = 2πf ₀ b / c, where b is the length of the baseline, f ₀ is the carrier frequency, and s is the speed of sound at the signal receiving point. Thus, α = arccos (Δφ ₁ / k). The phase shift Δφ _{2 of the} electrical signals of two point receivers (third and fourth) arriving at the inputs of the receiving path is related to the angle between the base line and the direction of arrival by the relation Δφ ₂ = kcosβ,

β = arccosΔφ ₂ / k. Introducing the auxiliary angles φ and Ψ (Fig. 2), we obtain that for a known depth H of the underwater object, the expressions for the coordinates of the underwater object X ₀ , Y ₀ relative to the center of the base. In this case, the plane with ordinate H is the third position surface. Obviously, cosΨ = D / R, where D is the distance, R is the slant range, cosΨ = x / D, cosα = x / R (cosΨcosφ) = (Dx) / (RD) = x / R, cosβ = y / R (cosΨcosφ) = (Dy) / (RD) = yR.

и дифферента γ. Дифферент не сказывается на значении у₀, а крен на значении х₀, ось X направлена вдоль продольной оси подводного объекта, а ось У направлена по траверзу. Исправленные путем учета крена и дифферента значения координат маяка можно записать следующим образом: х₁=Htg[arctg([0/H)+γ],

, где γ и

- положительные значения при опускания носа и правого борта.Moreover, cosα = cosΨcosφ, cosβ = cosΨsinφ, X ₀ = Hcosφ / tgΨ, Y ₀ = Hsinφ / tgΨ. Where do we get x ₀ = cHΔφ1 / a; at ₀ = cHΔφ2 / b. Since the plane of the deck almost never coincides with the horizon plane, the influence of roll angles is also taken into account

and trim γ. The trim does not affect the value of y ₀ , and the roll on the value of x ₀ , the X axis is directed along the longitudinal axis of the underwater object, and the Y axis is directed along the beam. The lighthouse coordinate values corrected by taking into account the roll and trim can be written as follows: x ₁ = Htg [arctg ([0 / H) + γ],

where γ and

- positive values when lowering the nose and starboard side.

Information on the coordinates of the drifting station relative to the underwater object allows us to solve the problem of the underwater object reaching the reference point, since it can easily be converted into the heading angle KU and distance D: KU = arctan (y, x),

. Решение обратной задачи дает возможность определить координаты подводного объекта на карте или планшете, на который предварительно наносится реперная точка. В том случае, когда определяется также наклонное расстояние до дрейфующей станции или донного приемоответчика, третьей поверхностью положения является сфера с радиусом, равным наклонному расстоянию. Формулы для вычисления координат упрощаются и имеют вид х₀=(сRΔφ₁₂)/α, у₀=(cRΔφ₃₂)/β.

. Solving the inverse problem makes it possible to determine the coordinates of an underwater object on a map or tablet on which a reference point is previously applied. In the case where the inclined distance to the drifting station or the bottom transponder is also determined, the third position surface is a sphere with a radius equal to the inclined distance. The formulas for calculating the coordinates are simplified and have the form x ₀ = (cRΔφ ₁₂ ) / α, y ₀ = (cRΔφ ₃₂ ) / β.

Each receiving hydroacoustic antenna consists of four hydrophones. The antenna section consists of two single-channel and one two-channel module, located on a linear carrier bracket. The distance between the receiving hydrophones of the two-channel module is 50 mm. The maximum spacing of the extreme receivers on the bracket is 1000 mm. The bracket is perforated, which allows the receivers to be located in close proximity to each other for phase calibration and with arbitrary spacing for measuring the direction of arrival of the acoustic signal. Piezoceramic spheres with a diameter of 30 mm are used as hydrophone receivers, inside of which preliminary amplifiers with a gain of 30 dB are placed. The spheres are placed on a steel plate measuring 145 × 145 × 10 mm, equipped with fasteners and an acoustic plug on the back side. The suppression ratio of the audio signal from the back is at least 30 dB.

The antenna complex consists of an 8-channel 2-section receiving hydroacoustic antenna and a hydroacoustic emitting antenna. Each section of the receiving antenna is a 4-element non-equidistant hydrophone module designed to measure the projection of the acoustic signal arrival vector onto one of the horizontal axes in the ultrashort base mode, in the direction finding mode, or for receiving signals in the long base mode at 4 operating frequencies. Sections of the receiving antenna are located in a horizontal plane perpendicular to each other.

Thus, when all hydrophones receive at the same operating frequency, the mode of determining the delay and direction of arrival of the response from a fixed drifting station or bottom transceiver in the ultrashort base mode is implemented, and when each of the hydrophones is tuned to its operating frequency, the measurement mode delays from several bottom transponders and drifting stations in long base mode.

The system for transmitting information through a sonar channel at an underwater object is implemented using standard sonar communication equipment. In this case, as devices for the formation and processing of signals, both hydroacoustic equipment providing hydroacoustic communication mode and additional devices in the form of consoles connected to their transmitting and receiving paths can be used.

As location signals, tonal signals with a frequency of 3 kHz are used, emitted both in automatic mode according to a special program and in a request mode.

For information transmission systems based on the use of tonal signals, the noise immunity of the system is determined by the noise immunity of the “On” signal detectors and information signal detectors. To detect “On” signals, which are a segment of harmonic oscillations, the non-optimal incoherent reception method was used, which provides broadband reception with integration after detector 22. Functionally, the circuit includes FCN 18, which provides preliminary amplification and formation of an omnidirectional spatial channel from the antenna of the drifting station, a broadband filter of 19 s band ΔFш, limiter 20 and narrow-band filter 21 with band ΔFy, forming a circuit that provides, under the condition Fш / ΔF >> 1, stabil interference and suppression of pulsed (broadband) interference and provides equalization of the interference spectrum at the input of the limiter 20, a narrow-band filter 21, which provides the formation of operating frequencies, a detector 22 having a linear characteristic, an integrator 23, which is a low-pass filter with an effective passband ΔFu = 1 / T, where T = 2 sec (symbol duration), a threshold circuit 18 constructed on the basis of the Neumann-Pearson criterion, since the probability of a signal appearing at its input is significantly lower than the probability of its absence.

Functional diagram of the signal processing (Fig. 5) includes a broadband filter 25 with a band ΔFш, a limiter 26 and a narrow-band filter 27 with a band Δfy, which form a circuit that provides, under the condition ΔFш / ΔFy >> 1, the stabilization of interference and suppression of pulsed (broadband) interference and equalization of the interference spectrum at the input of the limiter 26, the detector 28 having a linear characteristic, an integrator 29, which is a low-pass filter with an effective passband ΔFu = 1 / T, where T = 0.5 sec (symbol duration), selection scheme maximum 34, weight The current selection of the maximum signal for subsequent comparison with a given threshold, the threshold circuit 33, constructed on the basis of the ideal observer criterion, since the weight of errors of the type “false alarm” and type “signal skip” can be considered the same, the threshold in the circuit is selected from the condition of minimizing the total the probability of error, in this case, after exceeding the threshold, a command is received in the maximum selection circuit 34 that disconnects the channel with the maximum signal. Thus, the signal processing when receiving a message is reduced to the detection of individual tones with probabilities F and D such that the sum of F + (1-D) does not exceed 0.01, with F + 1-D. The satellite communications module is designed to form packages and control algorithms for the transmitted information to the bottom transponders.

Unlike the known device in the proposed device, a drifting station equipped with appropriate equipment, while in drift, has the ability to continuously receive signals from low-orbit and medium-orbit satellite navigation systems, process them with the determination of high-precision eigen coordinates at any time, and also determine the actual location of the bottom transponders . At a certain point in time (according to a request signal from an underwater object or according to the work program of a drifting station), this information is transmitted via a hydroacoustic channel in the form of a noise-like encoded signal of a certain format directly to an underwater object or to bottom transponders. Having determined its coordinates relative to the drifting station and having information about the geographical coordinates of the latter, the underwater object performs its own coordination in the geographical coordinate system.

To increase the power supply resource of bottom transponders, they work only in periodic mode. Their switching on and off is carried out according to signals from a drifting station.

The source of information

1. RF patent No. 2032187.

Claims (1)

A hydro-acoustic navigation system containing a navigation base of M hydro-acoustic transponders with different response frequencies and a hydro-acoustic transceiver located on the navigation object, by which time propagation intervals of the signals are measured with their subsequent conversion into the distance between the underwater object and the hydro-acoustic transponders, characterized in that the receiving hydro-acoustic antenna consists of four hydrophones, each section of the antenna consists of two one anal and a multichannel modules mounted on a linear bearing bracket, taken perforated, antenna receivers are in the form of a spherical surface and placed on a steel plate, at least one of M hydroacoustic transponders mounted on the water surface.

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