RU2624980C1 - Hydroacoustic rho-rho navigation system - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: system consists of a navigational base permanently located at the bottom or in depth of the water area at points with known coordinates which do not change during the object's navigation cycle, an impulse-code signal generation and emission unit, a receiving and primary signal processing unit including one multichannel receiver and a computing unit, wherein the parameters of all/several impulse-code signals received on the navigation object are determined from each transponder, and identifications of impulse entries along the ray trajectories are made by performing calculations of the structural functions of the entries for all transponders and determining the exact distances to each lighthouse on the basis of all/several entries.

EFFECT: increasing accuracy and reliability of measuring distances and underwater positioning of software under conditions of multibeam transmission of navigation signals in shallow water areas while reducing the technical complexity and power consumption of the system.

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Description

The invention relates to sonar navigation systems, specifically to systems using pulsed methods for determining distances between navigation objects and transponders of acoustic signals.

Global radio frequency positioning systems (GLONASS / GPS / Galileo / IRNSS / Compass / QZSS) can solve the problems of positioning, navigation and time synchronization (PNT) of technical systems for both military and civilian purposes and applications. However, signals with radio frequencies used by these systems cannot penetrate sea water, and can be used to position underwater devices (PU).

Underwater devices and apparatuses use inertial measuring devices (IMUs) to navigate underwater. But number calculators can be the only means of underwater navigation only for short-duration missions, since the accumulated error of the inertial number system ultimately requires external corrective measurements to maintain or restore accurate operation.

It is known that the propagation of pulsed acoustic signals in underwater channels is associated with a number of problems. These include - time-varying multipath propagation of signals and delays of pulse signals when propagating along the rays, limiting the frequency bandwidth of the channel bandwidth, the presence of environmental and industrial noise, etc. The most strongly indicated effects are manifested in the conditions of shallow water distribution channels - on the shelf, in bays, straits and inland seas and water bodies, as well as in the water areas of shallow seas covered with ice.

In 1996, Kongsberg Maritime AS (https://www.km.kongsberg.com/) developed the HiPAP® (High Precision Acoustic Positioning) navigation system. This system has modifications for a large number of applications, including positioning of drilling vessels, positioning of loading at sea, positioning of laying cables and pipelines, etc. HiPAP® systems are capable of navigating and positioning underwater devices at distances up to 4000 meters using powerful deep-sea transceivers. To increase the accuracy and reliability of positioning, an increase in the radiation power of transmitters is used to increase the signal-to-noise (S / N) ratio, the output of transceivers to zones without obstacles or air bubbles between them and allowance for bending or deflection of the beam due to different temperatures in the water column, transceivers with a radiation pattern are also used. HiPAP systems have built-in algorithms for calculating the deviation of a sound beam when it propagates in an aquatic environment, as well as algorithms for compensating for errors caused by this effect. To suppress noise and maximize sensitivity in the direction of the transponder mounted on the control panel, Kongsberg Maritime AS uses specially designed transceivers with a narrow beam pattern.

The disadvantages of this positioning system is the placement of equipment for measuring ranges and the positioning of the launcher on the escort vessel, as well as manual control by the operator of the navigation system. The use of high-power transponders to obtain an excess of the useful signal over noise near the escort vessel requires the availability of powerful power sources for the control panel or control panel and must receive electricity via cable. These requirements limit the range of tasks to be solved mainly by operations with towed devices in a small spatial area of launcher positioning (maximum 4000 meters) relative to the escort vessel.

The well-known "Hydroacoustic navigation system" (clause of the Russian Federation No. 2477497 C2), including a navigation base of M hydroacoustic transponders with different response frequencies and equipment located on the navigation object for measuring the time intervals of signal propagation with their subsequent conversion in the distance between the navigation object and the navigation hydroacoustic transceivers base, as well as a navigation computer for determining the coordinates of the navigation object with the appropriate mathematical software Niemi. Part of the M-transponders is fixed on the seabed, the rest are installed on the water surface and are equipped with signal receivers of satellite radio navigation systems. The antenna of the transceiver of the navigation object is made with an electronically controlled form of directivity.

The use of buoys on the surface as carriers of sonar transponders in the indicated system limits the possibility of operating the navigation system, in particular in stormy conditions, in water areas with ice cover and in areas with developed shipping (fishing). In addition, the proposed system will effectively measure distances by the time of arrival of the pulse and the selected angle on the transponder only for signals propagating along the "direct" beam. Also, for shallow sea waveguides, several pulses will arrive at the receiver, coming out at different angles and experiencing a different number of reflections from the boundaries (Rodriguez O., Jesus S. Physical limitations of travel time based shallow water tomography. J. Acoust. Soc. Am. 108 (6), December 2000, p. 2817). The error of distance measurements in this case will be proportional to the time interval of arrival of all pulses from a particular beacon.

The well-known "Hydroacoustic navigation system" (p. RF №2371738 C1). The system contains a navigation base of M hydroacoustic transponders with different response frequencies and a hydroacoustic transceiver located on the navigation object, which measures the time intervals of signal propagation with their subsequent conversion in the distance between the underwater object and hydroacoustic transponders, at least one of which is installed on the water surface . 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.

The disadvantages of this technical solution are associated with the use of surface buoys drifters as repeaters and reference beacons transponders. The navigation system will be of limited use in shallow water areas, in coastal and shelf zones due to the strong influence of wave and wind loads, uncontrolled drift, in ice-covered areas or in areas with drift ice, in areas of developed shipping and fishing, due to the increased risk of destruction. The presence of a large number of transponders for navigation signals, information exchange signals between surface drifters, bottom beacons and underwater devices, having individual operating frequencies, will occupy a wide frequency range and lead to a number of frequencies beyond the optimum sound propagation frequencies in specific areas, which will lead to deterioration of performance in terms of range and reliability of positioning. The use of two positioning systems (with a short base and a long base) in one navigation system, an acoustic information exchange system and a radio frequency positioning system increases the power consumption, increases the number of technical and electronic components, which increases the likelihood of technical failures. We also note that solving real-time navigation and information exchange tasks will require computing resources that can work with large volumes of information with high performance, which may impose restrictions on the use of the system in terms of weight and size and power supply for controllers and transponders.

A number of hydroacoustic navigation systems are known, consisting of several hydroacoustic transponders (beacons) located on the surface and (or) the bottom of water areas and devices located on the navigation object: devices for interrogating beacons, calculating the distance from the measured signal propagation time and sound velocity in the water environment and calculating the coordinates of the object according to the found values of the distances (RF patents No. 713278 U1, 2032187 C1). These systems are designed to increase the range and accuracy of determining coordinates for the conditions of refraction and multipath propagation of navigation signals.

In a known solution (RF patent No. 713278 U1), the navigation system contains a bottom navigation base of M hydroacoustic transponders with different operating response frequencies and a hydroacoustic transmitter located on the navigation object, the input of which is connected to the output of the clock generator, an M-channel receiver, the outputs of which are connected to the inputs of M meters of propagation times of hydroacoustic signals to a transponder operating at the frequency of this channel and vice versa, the second inputs of which are connected to the outputs of eratora clock, and coordinates calculator navigation object. In order to increase the accuracy of determining coordinates under refraction and multipath conditions, the number of types of possible trajectories of N - blocks of converters of time intervals in distance has been introduced into each of the M channels.

The disadvantage of such a navigation system is the error in determining the coordinates due to the fact that the time of arrival of the signal is determined by the leading edge of the signal, analogously, using a threshold discriminator. Signals with a level below the threshold are not measured. For signals with levels above the threshold, the accuracy of measuring the time of arrival of the pulse depends on the steepness of the leading edge. Also, due to the use of simple tonal pulses, there is a possibility of interference in the receive channels, which will be accepted as a useful signal. In this case, the propagation time meter, which is triggered from the first of the received signals, will record the arrival time that is different from the real one, which will lead to a shift in the current maximum number and an uncontrolled error in determining the coordinates of the object.

In the closest to the claimed solution, a hydroacoustic synchronous rangefinder navigation system is proposed, which allows to reduce the error in determining the coordinates of the navigation object (paragraph RF No. 2032187 C1). The system contains a bottom navigation base of M hydroacoustic transponders with different response frequencies and a hydroacoustic transmitter, a clock generator, an M-channel receiver, M meters of propagation time of hydroacoustic signals to and from transponders, M × N blocks for converting time intervals to distances N in each of the M channels, M blocks for selecting the maximum distance value from N values and a coordinate calculator for the navigation object. N-1 additional meters of propagation time, N-1 delay multivibrators, N-1 strobe multivibrators, N-1 selectors were introduced into each of the M channels. According to the number of types of N ray paths, N (N-1) additional blocks for converting time intervals into distances, N-1 blocks for selecting the maximum distance value and distance averager are introduced into each of the M channels. The outputs of all blocks for selecting the maximum value are connected to the N inputs of the distance averager, and the output of the distance averager is connected to the input of the computing device of the coordinates of the navigation object.

The main disadvantage of this solution is that in each cycle of determining the distances to each of the M beacons, the arrival times of pulses from 1 to N are measured, the time of each arrival is recalculated into the distance, and all distances are averaged. It does not take into account that the number of pulse arrivals in each cycle can differ from N, pulse arrivals can appear or disappear from cycle to cycle, which does not allow us to unambiguously identify the trajectories along which specific pulses propagated and correctly calculate the distances to the beacons (Half Yu. A. Error Correction and Selective Tracking of Pulses in Acoustic Sensing Streaming Data, Underwater Research and Robotics, No. 2/20, Vladivostok, Dalnauka Publishing House, IPMT, 2015, pp. 40-46). The use of averaging over all measurements will not lead to a decrease in the error, since due to errors in the identification of trajectories, an increase in the error of all measurements occurs. Registration of any pulse noise signals in the operating frequency band and during the measurement cycle will also lead to erroneous values of arrival times (and recalculated distance values) at times after the noise pulse and until the end of the measurement time. We also note that as a result of inter-beam interference, the amplitude-time parameters of the pulses are complex, delayed, and the leading edge parameters of the signals change, which also leads to a decrease in the accuracy of the operation of such circuit elements as the system for measuring propagation time, selecting the maximum value, and multivibrators pulses and delays.

The task is to develop a hydroacoustic rangefinder navigation system for the conditions of multipath propagation of navigation signals in the shallow sea, on the shelf, in bays, straits, and water areas covered with ice.

EFFECT: increased accuracy and reliability of measuring distances and underwater positioning of navigation objects in the conditions of multipath propagation of navigation signals in shallow waters.

The problem is solved by a hydroacoustic rangefinder navigation system that includes a navigation base of at least three acoustic beacons M _n for n≥3, for example, M ₁ , M ₂ and M ₃ , which are stationary in the water at points with known coordinates that take Ko kodoimpulsnye and radiating spread spectrum signals K _1, K ₂ and K _3, respectively, with the frequency FM and filling placed on the navigation object generation unit and signal radiation, comprising an electric generator-shaper kodoimpulsn of the first signal of the survey of navigation beacons, the transmitter of the acoustic code of the pulse signal of the survey of navigation beacons and a timer with a clock generator for starting the generator-generator and transmitter of the code of the polling signal, a unit for receiving and processing the signals from a single multi-channel receiver, an amplifier of code-pulse electrical signals, a band-pass filter with central frequency fm, for filtering code-pulse electrical signals and an analog-to-digital converter of code-pulse electric signals, and a computing device including a memory unit, an electronic switch unit, signal correlator blocks SK _n from beacons M _n , maximum search units and determination of pulse propagation time for a signal from beacons, distance determination units for signals from beacons, and an object coordinate calculation unit navigation.

The use of spread-spectrum code pulse signals with a tonal filling frequency allows the use of “transparency windows” of acoustic channels — a limited frequency range with a slight attenuation and the use of one multi-channel receiver for signals from all beacons on an underwater object, which increases the accuracy and reliability of distance and underwater measurements positioning in the conditions of multipath propagation of navigation signals in shallow waters compared to the prototype. In addition, the use of navigation signals in the form of spread-spectrum code-pulse signals provides an additional advantage due to the additional increase in the signal-to-noise ratio due to the coordinated (correlation) signal processing at the beacons and the underwater object during reception. Digital conversion and digital signal processing to extract pulses, avoids the use of a large number of analog multi-link amplitude-time comparators in each of the M channels in the prototype, performing the specified procedure in the proposed system in the form of a standard procedure for the exact maximum search for the time function of the cross-correlation coefficients of digital masks and the signal from the receiver, while due to the use of digital coding, this process is performed using computationally device in parallel (synchronously) for signals from all transponders and, with the necessary performance of a computing device (WU), in real time. The propagation time of acoustic pulses from beacons is determined by the method of measuring the structure of the impulse response function in time in an inhomogeneous medium (Cl. RF No. 2577561). To do this, in each of the M channels, after recording pulse (ray) arrivals, their number is determined and the structural function of arrivals is constructed (that is, the relationship between previous measurements and current ones is determined), thereby eliminating errors associated with variations in the signal amplitude over time - disappearance or appearance new highs, as well as changes in the number of highs in the measured series. The pulse arrival time is determined absolutely precisely - as the position of the maximum point on the time axis, while in the prototype, the pulse arrival time is determined depending on the set level of the amplitude comparator and on the type of the leading edge of the determined pulse.

Below, for simplicity, a description is given of the scheme and operation of the system, including the declared minimum of transponder beacons, (although the number of transponder beacons is not limited and can be any more than three).

In FIG. 1 (a, b) shows a structural diagram (block diagram) of the inventive system for three beacon transceivers, where

(a) a diagram of the exchange of navigation signals and interrogation signals between an underwater object and beacons.

(b) - block diagram of the inventive system:

M1, M2, M3 - navigation acoustic beacons transponders;

Software - object of navigation;

Kо - code acoustic pulse signal for interrogating beacons from an underwater device with a filling frequency fm;

K ₁ , K ₂ , K ₃ - code pulsed acoustic navigation signals from beacons of transponders;

P (λ, ϕ, z) - spatial coordinates of the underwater device;

P _i (λ _i , ϕ _i , z _i ) - spatial coordinates of beacons of transponders;

h - depth sensor;

Signal Generation and Emission Unit (BFI)

2 - transmitter code acoustic pulse signal polling navigation beacons;

21 - generator-driver of the electric code-pulse signal of the survey of navigation beacons;

11 - timer with a clock generator for starting the generator-shaper 21 and the transmitter of the code signal of the poll 2;

Block of reception and primary signal processing (BPPO)

3 - single-channel receiver - acoustoelectric transducer - code-pulse acoustic signals from navigation beacons;

31 - amplifier code pulse electrical signals;

32 - band-pass filter with a central frequency fm, for filtering code-pulse electrical signals;

33 - analog-to-digital Converter (ADC) code-pulse electrical signals;

Computing device (WU)

44 - memory block;

45 - electronic switch;

4_1 - block correlator signal SK1 from the beacon M1;

4_2 - block correlator signal SK2 from the beacon M2;

4_3 - block correlator signal SK3 from the beacon M3;

5_1 - block search for maxima in the dependence of the correlation coefficient on time and determine the propagation time of the pulses for the signal from the beacon M1;

5_2 - block search for maximums depending on the correlation coefficient on time and determine the propagation time of the pulses for the signal from the beacon M2;

5_3 - block search for maxima in the dependence of the correlation coefficient on time and determine the propagation time of the pulses for the signal from the beacon M3;

6_1 - block determining distances for signals from the beacon M1;

6_2 - block determining distances for signals from the lighthouse M2;

6_3 - distance determination unit for signals from the M3 beacon;

7_1 - block determining the average distance from the lighthouse M1;

7_2 - block determining the average distance from the lighthouse M2;

7_3 - block determining the average distance from the lighthouse M3;

10 - block calculating the coordinates of the navigation object.

In FIG. 2 shows a diagram of the processing of digital data in the units of the WU.

In FIG. 3 shows the results of digital processing of received signals from beacons in units of the pilot unit, in a graphical form, sequentially in time, over time, where

(a) - the result of the correlation processing of signals from beacons (blocks 4_1, 4_2 and 4_3).

(b) - the result of the search for the maxima and determination of the propagation time of the pulses from the beacons (blocks 5_1, 5_2 and 5_3).

(c) - the result of constructing the structural function of pulse arrivals from beacons for the second and subsequent cycles (blocks 5_1, 5_2 and 5_3)

The positioning and navigation of the navigation object (software) of the claimed system is as follows. Beacons transponders are placed stationary at the bottom or in the depth of the water area at points with known coordinates that do not change during the navigation cycle of the object. Then, in successive cycles, including the process of interrogating the beacons, receiving, filtering, converting and registering signals from the beacons, extracting the code-pulse signals coming from the beacons along various paths and determining their parameters, determine the distances to the beacons and perform positioning in the coordinate system of the beacons. These processes are performed as follows: at time t ₀ (the beginning of the first positioning cycle), the timer with the clock generator 11 includes a clock generator, which sends a signal to start the generator-generator 21 of the interrogation code signal polling Ko. The same signal turns on the transmitter 2 and the block of reception and primary signal processing (BPPO). The first code-pulse polling signal Ko from the generator 21 is supplied to the input of the transmitter 2, amplified and radiated into the aquatic environment. The acoustic interrogation signal emitted into the aquatic environment is a code pulse acoustic pulse of an extended spectrum of Ko with a filling frequency of fm. Navigation beacons transponders M ₁ , M ₂ , M ₃ , at time t ₁ , t ₂ and t ₃ respectively, receive and isolate the 1st code-pulse signal Ko from a series of signals Ko _i , i = 1, 2 ... n _m , where i are numbers, an _m is the number of intrinsic rays along which the polling signals propagate from the software to each beacon, m = 1, 2, 3. The first pulse corresponds to the propagation along the shortest path of sound propagation between the software and each beacon by the transponder. Then, at times t ₁ + Δ, t ₂ + Δ and t ₃ + Δ, where Δ is the specified delay, transponders emit code-specific signals K ₁ , K ₂ and K ₃ unique for each beacon.

The signals K ₁ , K _2, and K ₃ emitted by the M beacons propagate in the opposite direction from the beacons to the PO, experiencing reflections from the boundaries and refracting on inhomogeneities in the acoustic channel and, together with the surrounding acoustic noise, are received by one multichannel receiver 3 of the receiving and primary processing unit signals (BPPO), made in the form, for example, of an acoustoelectric transducer, the electric signal S from the receiver 3 is supplied to the amplifier 31 and amplified in the working frequency band fm, after which it enters the band-pass filter 32 from the center noy frequency of the FM transmission. After filtering, the electrical signal is fed to an analog-to-digital converter (ADC) of the electrical signals 33. The results of acoustic measurements and their initial processing from the ADC output, in digital form Sd, are transmitted to the WU computing device. The above operations are performed from time t ₀ continuously, in real time, until the end of the software positioning cycle.

The results of primary processing of acoustic measurements in digital form Sd transmitted to the control unit are transferred to a memory unit 44, which is connected to a memory data sampling and control unit (electronic switch) - 45, which, in turn, is connected to a timer and a clock generator 11 to bind the primary results acoustic measurements to the current values of time t _i in the positioning cycle - Sd (t _i ) and the direction of the resulting digital data array in parallel to the three processing channels (Fig. 2).

Each output of the switch is connected to the inputs of digital correlator blocks that perform correlation processing: in block 4_1, the current time correlation coefficient SK ₁ (t _i ) is calculated between the received signal Sd and the digitized code pulse acoustic navigation signal (“electronic mask”) K ₁ d from the lighthouse M ₁ . In block 4_2, the current time correlation coefficient SK ₂ (t _i ) is calculated between the received signal Sd and the digitized code pulse acoustic navigation signal (“electronic mask”) K ₂ d from the beacon M ₂ . Block 4_3 calculates the current time correlation coefficient SK ₃ (t _i ) between the received signal Sd and the digitized code pulse acoustic navigation signal ("electronic mask") K ₃ d and code pulse acoustic navigation signal K ₃ from the beacon M ₃ . In FIG. 3 (a) shows the form of the correlation coefficient according to the results of calculations in blocks of digital correlators.

The digital values of the correlation coefficients SK ₁ , SK _2, and SK ₃ calculated from the signal masks for each beacon come from the outputs of the correlation blocks 4_1, 4_2 and 4_3 to the inputs of the blocks 5_1, 5_2 and 5_3 of searching for the maximums of the correlation coefficients depending on time and time pulse propagation for signals from beacons M ₁ , M ₂ and M ₃ . The search for the maxima is carried out on the basis of a specified criterion, according to which the maximum correlation values should exceed by 20% the correlation values of the "electronic masks" of the signals K ₁ d, K ₂ d and K ₃ d with the received ambient noise signal Sш. The positioning cycle ends by the criterion of redundancy - when the number of detected maxima for all processing channels (for all beacons) exceeds 10 maximums (Fig. 3b) or by the criterion of limited reverberation when the period of time from the moment of detection of the last current maximum for all processing channels (for all beacons) exceeds the value 0.2 × T _1Mi , where T _1Mi is the propagation time of the first pulse to each beacon. The maximum search results in each block 5_1, 5_2 and 5_3 are of the form {N, t ₀ , n, τ _n , A _n }, N = [1, 2, 3] - block (beacon) number, t ₀ - cycle start time , n = [1, 2 ... 10] is the number of the maximum, τ _n - [1, 2, ... 10] is the position of the maximum on the time axis, A _n are the amplitudes of the maximum.

The propagation times of all pulses (maxima) from all beacons to the TNmn software in the first positioning cycle are calculated from the found positions of the correlation maxima in blocks 5_1, 5_2 and 5_3, using time synchronization of data using a timer and clock generator 11 using the formulas given in the table one.

In the second and all subsequent measurement cycles (t _n , n> 0) in blocks 5_1, 5_2 and 5_3, after finding the maxima of the correlation coefficients, to identify the numbers of incoming pulses, the structural function of the arrival times of the recorded pulses is calculated in the form of FIG. 3 (c), in accordance with the expression (1):

(например, патенту РФ №2577561). После чего определяются порядковые номера и характеристики приходящих импульсов в текущем цикле измерений - амплитуда и положение на оси времени {N, t_k, n, τ_k, A_k}, для каждого сигнала от маяков M1, М2 и М3 (фиг. 3в). Времена распространения всех импульсов (максимумов) от всех маяков до ПО - TNmn рассчитываются по положениям максимумов корреляции в блоках 5_1, 5_2 и 5_3, с использованием временной синхронизации данных с помощью таймера и генератора синхроимпульсов 11 по формулам, приведенным в Таблице 2:where S _{i, i + 1, m is the} two-dimensional Euclidean distance between all maxima A _{m, i} in successive data blocks

(for example, RF patent No. 2577561). After that, the serial numbers and characteristics of the incoming pulses in the current measurement cycle are determined - the amplitude and position on the time axis {N, t _k , n, τ _k , A _k }, for each signal from the beacons M1, M2 and M3 (Fig. 3c) . The propagation times of all pulses (maximums) from all beacons to software - TNmn are calculated according to the positions of the correlation maxima in blocks 5_1, 5_2 and 5_3, using time synchronization of data using a timer and a clock generator 11 according to the formulas shown in Table 2:

The values of the propagation times of the pulses T1mn, T2mn and T3mn calculated in blocks 5_1, 5_2 and 5_3 are transmitted to blocks 6_1, 6_2 and 6_3, where the distances from the software to the beacons from the eigen beams D1j, D2j and D3j are determined (j = 1, 2 ... 10) M1, M2 and M3, respectively. To calculate the distances, well-known models of the propagation of intrinsic rays in a waveguide can be used, with environmental parameters in the area of the beacons and software positioning.

The distance values calculated from the eigenbeams D1j, D2j and D3j (j = 1, 2 ... 10) from the software to the beacons M1, M2 and M3, respectively, are transmitted digitally from blocks 6_1, 6_2 and 6_3 to blocks 7_1, 7_2 and 7_3 to determine the calculated (exact) distances D1, D2 and D3. To calculate the exact distances, a circuit can be used with averaging the distances over all pulses (natural rays) received in the measurement cycle and / or a scheme for selecting the group of the most stable or having maximum amplitude pulses and determining the exact distances from these pulses.

The values of the distances D1, D2 and D3 are transmitted to block 10 for performing software positioning by the triangulation method (with specification of the values for the measured depth h) relative to the beacons M1, M2 and M3 and calculation of the absolute geographical coordinates of the software. The second and subsequent positioning cycles end according to the redundancy criterion - when the number of detected maxima for all processing channels (for all beacons) exceeds a specified number of maxima or according to the criterion of limiting the reverberation time, when the period of time from the moment of detection of the last current maximum for all processing channels (for all beacons) exceeds the value 0.2 × T _1Mi , where T _1Mi is the propagation time of the first pulse to each beacon.

Thus, the proposed design of a hydroacoustic navigation system allows you to get the claimed technical result - improving the accuracy and reliability of measuring distances and underwater positioning of software in the conditions of multipath propagation of navigation signals in shallow waters while reducing technical complexity and power consumption, through the use of single receivers and single-frequency navigation transmitters signals at beacons and software, by increasing the signal-to-noise ratio at and using, in accordance with the signals, digital processing and by measuring the propagation time of the signals and determining the distances to the beacons and positioning in space from the measured parameters of the own beams (pulses), for which, in order to eliminate errors, identification, verification and tracking in time are performed.

Claims (2)

1. Hydroacoustic rangefinder navigation and positioning system, including a navigation base permanently located in the water area at points with known coordinates from M _n acoustic beacons for transponders receiving and emitting pulsed signals, and a signal generation and emission unit, a signal receiving and primary processing unit, located on the navigation object signals and computing unit coordinate navigation object, characterized in that the base includes M _n beacon transponders with n≥3, as pulse signals isp lzuyut kodoimpulsnye spread spectrum signals Km _n with the carrier frequency of the FM block formation and signal radiation comprises a generator-shaper electric kodoimpulsnogo signal Ko survey navigation beacons M _n, the transmitter code of the acoustic pulse signal interrogation navigation beacons and timer clock generator for generator start-shaper and the polling code signal transmitter, the signal receiving and primary signal processing unit consists of a multi-channel receiver, a code-pulse amplifier an insulating signals, a bandpass filter with a center frequency of the FM for filtering kodoimpulsnyh electrical signals and analog-to-digital converter kodoimpulsnyh electrical signals, and the computing unit comprises a memory unit, an electronic switch block correlators SK _Mn signal from the beacons M _n, the search blocks maxima and determining the propagation time pulses for signals from beacons M _n , distance determination blocks for signals from beacons M _n connected to a unit for calculating coordinates of a navigation object. 2. Hydroacoustic rangefinder navigation and positioning system according to claim 1, characterized in that a single acoustoelectric transducer is used as a multi-channel receiver.

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