RU2289149C2 - Hydro-acoustic synchronous long-range distance measuring navigation system - Google Patents

Abstract

FIELD: hydro-acoustic navigation systems, applicable for navigation support of long-range underwater vehicles.

SUBSTANCE: the hydroacoustic synchronous long-range distance measuring system has a bottom navigation base of M hydroacoustic transponders with different reply frequencies f_m (m=1-M), sync pulse oscillator, acoustic transmitter with sampling rate f₀, whose input is connected to the first output of the sync pulse oscillator, M-channel receiver for reception of reply signals with frequencies f_m, M meters of the time of propagation of acoustic signals to the transponder operating at the frequency of this channel and back, whose first inputs are connected to the outputs of the M-channel receiver, and the second inputs are connected to the second output of the sync pulse oscillator, MxN conversion units of the time intervals to distances according to the Number of probable beam trajectories, whose inputs are connected to the outputs of the respective meters of propagation time, M units of selection of the maximum value of distance, whose inputs are connected to the outputs of N units of conversion of time intervals to the distances of the given channel, and a computer of the navigation object co-ordinates, whose first input is connected to the outputs of the units of selection of the maximum value of distance of all M channels. Besides, the hydroacoustic synchronous distance measuring navigation system has the second bottom navigation base of M hydroacoustic beacons - pingers with different emission frequencies F_m (m=1-M) mechanically linked with the respective M responder beacons containing M synchronously operating sync pulse oscillators, M transmitters with different operating frequencies F_m, whose inputs are connected to the outputs of the sync pulse oscillators, M hydroacoustic radiators with operating frequencies F_m, whose inputs are connected to the outputs of the transmitters with the respective operating frequencies, located on the navigation object are the second sync pulse oscillator operating synchronously with the sync pulse oscillators of the beacons-pingers, whose first output is used for synchronization of M synchronously operating sync pulse oscillators of the hydroacoustic beacons-pingers before their installation on the sea-floor, towed receiving acoustic aerial, the second M-channel receiver for reception of acoustic signals of the beacons-pingers, whose input is connected to the output of the towed receiving acoustic aerial, M meters of the time of propagation of acoustic signals from the beacons-pingers to the navigation object, whose first inputs are connected to the outputs of the second M-channel receiver, and the second inputs are connected to the second output of the second sync pulse oscillator, additional M units of conversion of time intervals to distances, whose inputs are connected to the outputs of M meters of the time of propagation of acoustic signals from the beacons-pingers to the navigation object, and the outputs are connected to the second inputs of the computer of the navigation object co-ordinates, and the towed receiving acoustic aerial are located near the sea floor at a distance of not more than the wavelength at operating frequencies F_m. Additional M units of conversation of time intervals to distances compute desired distances r_m from measured propagation times t_m.

EFFECT: provided determination of the navigation object co-ordinates at short and long distances with a minimal error.

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Description

The invention relates to the field of sonar navigation systems and can be used for navigation support of underwater vehicles of increased range, for example, operating in ice conditions, making it difficult for the supply vessel to access them

Known sonar synchronous rangefinder navigation system [1], consisting of a base of sonar transponders used to measure the propagation time of acoustic signals from the navigation object to the beacons, a device for calculating the distance from the measured propagation time and the known speed of sound, and a device for calculating the coordinates of the navigation object from the found values distances.

The disadvantage of this system is the large error in determining the coordinates associated with the variability of the speed of sound in the marine environment.

Also known is a hydroacoustic synchronous rangefinder navigation system [2], containing a bottom base of M hydroacoustic transponders with different response frequencies, a transmitter located on the navigation object, the input of which is connected to the first output of the clock generator, an M-channel receiver whose outputs are connected to the inputs of the M meters the propagation time of hydroacoustic signals to the corresponding transponder and vice versa, the second inputs of which are connected to the second output of the clock generator c, M × N blocks for converting time intervals in distance according to the number N of possible ray paths, the inputs of which are connected to the corresponding outputs of the meters for propagation time, M blocks for selecting the maximum value, the inputs of which are connected to the outputs of N blocks of each of the M channels for converting time intervals in distance , the coordinate calculator of the navigation object, the input of which is connected to the outputs of the M blocks for selecting the maximum value.

The presence in the structure of the navigation system of blocks for converting time intervals into distances, operating according to an algorithm that takes into account the variability of the speed of sound and the effects of multipath, reduces the error in determining the coordinates. Such a system in technical essence is the closest to the proposed invention.

The disadvantage of this navigation system is the relatively short range when operating the navigation object near the bottom and when using bottom beacons responders, which is associated with the effects of refraction of sound near the bottom.

The technical solution is based on the task of developing a sonar synchronous navigation system with a longer range without increasing the error in determining the coordinates of the navigation object.

The problem is solved in that the composition of the long-range hydroacoustic synchronous long-range navigation system containing a bottom navigation base of M hydroacoustic transponders with different response frequencies f _m (m = 1-M), a clock generator, an acoustic transmitter with a polling frequency placed on the navigation object f ₀ , the input of which is connected to the first output of the clock generator. M-channel receiver for receiving response signals with frequencies f _m , M measuring the propagation time of acoustic signals to a transponder operating on the frequency of this channel and vice versa, the first inputs of which are connected to the outputs M of the channel receiver, and the second inputs are connected to the second output of the clock generator , M × N blocks for converting time intervals in distance according to the number N of possible ray paths, the inputs of which are connected to the outputs of the corresponding measuring instruments for propagation time, M blocks for selecting max of the distance, the inputs of which are connected to the outputs of N blocks for converting time intervals to distances of this channel, the coordinates calculator of the navigation object, the first input of which is connected to the outputs of M blocks for selecting the maximum distance, an additional second bottom navigation base from M sonar pinger beacons with different radiation frequencies F _m (m = 1-M) mechanically associated with the corresponding M beacon transponders containing M synchronously operating clock generators, M sensors with different operating frequencies F _m , the inputs of which are connected to the outputs of the clock generators, M hydroacoustic emitters with operating frequencies F _m , the inputs of which are connected to the outputs of the transmitters with the corresponding operating frequencies.

In addition, the second synchronization generator is located at the navigation object, which works synchronously with the pinger beacon clock generators, the first output of which is used to synchronize the M synchronously operated ping beacon clock generators before being installed at the bottom, a towed receiving acoustic antenna, and a second M channel receiver for receiving acoustic signals of pinger beacons, the input of which is connected to the output of the towed receiving acoustic antenna, M measure the propagation time of acoustic signals from pinger beacons to the navigation object, the first inputs of which are connected to the outputs of the second M channel receiver, and the second inputs are connected to the second output of the second clock generator, additional M blocks for converting time intervals into distances, the inputs of which are connected to the outputs of M measuring the propagation time of acoustic signals from pinger beacons to the navigation object, and the outputs are connected to the second inputs of the coordinate computer of the navigation object, and M hydro-acoustic emitters of pinger beacons and a towed receiving acoustic antenna are located near the seabed at a distance of no more than a wavelength at operating frequencies F _m , and additional M blocks for converting time intervals into distances calculate the desired distances r _m through the measured propagation times t _m according to the formula:

where _{C P} is the propagation velocity of the near-bottom wave, previously calculated through the parameters of the boundary media of the water-seabed interface according to the formula:

where ρ ₁ , с ₁ - density and speed of sound in the bottom layer of water, ρ ₂ , с ₂ - density and speed of sound in the sedimentary layer of the seabed.

In the claimed long-range sonar synchronous long-range navigation system, the common essential features for her and her prototype are:

- long-range sonar synchronous long-range navigation system containing a bottom navigation base of M hydroacoustic transponders with different response frequencies f _m (m = 1-M);

- clock generator located on the navigation object, an acoustic transmitter with a sampling frequency f ₀ , the input of which is connected to the first output of the clock generator;

- M channel receiver for receiving response signals with frequencies f _m ;

- M meters of propagation time of acoustic signals to the transponder operating on the frequency of this channel, and vice versa, the first inputs of which are connected to the outputs M of the channel receiver, and the second inputs are connected to the second output of the clock generator;

- M × N blocks for converting time intervals into distances according to the number N of possible ray paths, the inputs of which are connected to the outputs of the respective measuring instruments for propagation time;

- M blocks for selecting the maximum distance value, the inputs of which are connected to the outputs of N blocks for converting time intervals in the distance of this channel;

- a calculator of coordinates of a navigation object, the first input of which is connected to the outputs of M blocks for selecting the maximum distance value.

A comparative analysis of the essential features of the claimed hydroacoustic synchronous rangefinder long-range navigation system and prototype shows that the first, unlike the prototype, has the following distinctive features:

- the second bottom navigation base of M hydro-acoustic pinger beacons with different radiation frequencies F _m (m = 1-M), mechanically associated with the corresponding M transponder beacons containing:

- M synchronously operating clock generators;

- M transmitters with different operating frequencies F _m , the inputs of which are connected to the outputs of the clock generators;

- M sonar emitters with operating frequencies F _m , the inputs of which are connected to the outputs of the transmitters with the corresponding operating frequencies;

- a second clock generator located at the navigation object operating synchronously with the clock generators of the pinger beacons, the first output of which is used to synchronize the M synchronous clock generators of the sonar beacons before they are installed on the bottom;

- towed receiving acoustic antenna;

- a second M-channel receiver for receiving acoustic signals of pinger beacons, the input of which is connected to the output of the towed receiving acoustic antenna;

- M meters of propagation time of acoustic signals from pinger beacons to the navigation object, the first inputs of which are connected to the outputs of the second M-channel receiver, and the second inputs are connected to the second output of the second clock generator;

- additional M blocks for converting time intervals into distances, the inputs of which are connected to the outputs of the M meters of the propagation time of acoustic signals from pinger beacons to the navigation object, and the outputs are connected to the second inputs of the coordinate computer of the navigation object;

- M hydro-acoustic emitters of pinger beacons and a towed receiving acoustic antenna are located near the seabed at a distance of not more than a wavelength at operating frequencies F _m ;

- additional M blocks for converting time intervals to distances calculate the required distances r _m through the measured propagation times t _m according to the formula:

where _{C P} is the propagation velocity of the near-bottom wave, previously calculated through the parameters of the boundary media of the water-seabed interface according to the formula:

where ρ ₁ , с ₁ - density and speed of sound in the bottom layer of water, ρ ₂ , с ₂ - density and speed of sound in the sedimentary layer of the seabed.

This combination of common and distinctive essential features provides a technical result in all cases for which legal protection is requested. It is this combination of essential features of the claimed device that made it possible to create a long-range hydroacoustic synchronous long-range navigation system, consisting of two subsystems that operate independently with frequency separation, which has a longer range without increasing the error in determining the coordinates of the navigation object.

Such a design of a long-range hydro-acoustic synchronous long-range navigation system in the form of two subsystems in which bottom beacon responders and bottom pinger beacons are mechanically interconnected but functionally separated allows the first subsystem based on bottom beacon responders to be used to determine the coordinates of a navigation object at short distances, as well as to determine the own geographical coordinates of the responder beacons and mechanically associated pinger beacons in the process of calibration of the navigation system. The second subsystem based on bottom pinger beacons with known geographical coordinates and different radiation frequencies, but low enough to provide a given range, serves to determine the coordinates of a navigation object over long distances.

To determine the coordinates of the navigation object with an extremely small error, the second subsystem uses a near-bottom wave of the boundary type, which propagates at the water-seabed interface. When the emitters of the pinger beacons and the towed receiving acoustic antenna are located near the seafloor at a distance of no more than a wavelength at operating frequencies F _{m, the} near-bottom wave dominates the total sound field, its amplitude decreases with distance according to the cylindrical law, the propagation velocity does not depend on the frequency and from the profile of the vertical distribution of the speed of sound in water, and is determined by the density and speed of sound of the boundary media at the water-seabed interface by the formula:

where ρ ₁ , c ₁ is the density and speed of sound in the bottom layer of water, ρ ₂ , c ₂ is the density and speed of sound in the sedimentary layer of the seabed.

The listed properties of the near-bottom wave make it extremely promising when developing sonar navigation systems with a long range and minimal error in determining the coordinates of the navigation object.

Compared with the known sonar synchronous rangefinder navigation system with a range of up to 15 km, the inventive system has a range of up to 100 km.

Based on the foregoing, we can conclude that the set of essential features of the claimed invention has a causal relationship with the achieved technical result, i.e. thanks to this combination of essential features of the invention, it has become possible to solve the problem.

Therefore, the claimed invention is new, has an inventive step, i.e. it does not explicitly follow from the prior art and is suitable for use.

The claimed sonar synchronous rangefinder long-range navigation system is illustrated in the drawing. In the drawing and in the description, the following notation:

1 _m - transponder of the m-th channel,

2 - transmitter of acoustic request pulses at a frequency f ₀ ,

3 - the first M channel receiver of acoustic response signals at frequencies f _m ,

4 _m - measuring the propagation time of acoustic signals to the transponder beacon and back in the m-th channel,

5 _m - block selection of the maximum distance in the m-th channel,

6 _mn (m = 1-M, n = 1-N) - block conversion of time intervals in the distance,

7 - calculator coordinates of the navigation object,

8 - the first clock generator,

9 _m is the clock generator of the m-th pinger beacon,

10m - transmitter of the m-th pinger beacon,

11m - emitter of the m-th pinger beacon,

12 is a second clock generator,

13 - towed receiving acoustic antenna,

14 - second M-channel receiver of acoustic signals of pinger beacons,

15 _m - measuring the propagation time of acoustic signals from the pinger beacon to the navigation object,

16 _m - an additional unit for converting time intervals in the distance of the m-th channel.

Hydroacoustic synchronous rangefinder long-range navigation system operates as follows.

Located on the navigation object, the first clock generator 8 starts the transmitter 2 of the acoustic pulses at the request frequency f ₀ and resets the counters M of the meters 4 _{m of} the propagation time of the acoustic signals to the beacon transponder and back in each channel. Acoustic signals propagating in the aquatic environment are received by 1 _m transponders, re-emitted and received by the first M channel receiver 3 acoustic response signals at operating frequencies f _m 3. The receiver-amplified 3 signals from the output of each channel go to the blocking input of each of the 4 _m meters the propagation time and lock with their leading edge the integrator of the pulse-time stamps of the clock generator 8, and information about the number of accumulated time stamps is transmitted in digital form from each integr torus in the respective blocks 6 _mn transformation distance in time slots N for each m-th channel. Different blocks of 6 _mn transformations of the same m-th channel differ in the values of the coefficients characterizing the type of ray path in the algorithm for converting the propagation time into an inclined distance. The values of the inclined distances found in blocks 6 _mn go to the inputs of blocks 5 _{m to} select the maximum distance values, and the maximum values of distances from the outputs of blocks 5 _m go to the first input of the calculator 7 coordinates of the navigation object. According to a similar scheme and well-known methods [1], the coordinates of the responder beacons and the pinger beacons mechanically connected with them are determined by the known coordinates of the navigation object in the calibration mode of the navigation base. If the navigation object is within the range of the first subsystem, then its coordinates are determined by the first subsystem.

At the same time, synchronously operating clock generators of 9 _m bottom pinger beacons launch 10 _m pinger beacon transmitters, which in turn feed excitation pulses to sonar emitters 11 _m pinger beacons, and the second clock generator 12 located at the navigation object resets the counters pulses - time stamps of meters 15 _{m of} propagation time of acoustic signals from pinger beacons to the navigation object. Acoustic signals emitted by pinger beacons with operating frequencies F _m propagate in the aquatic environment and are received by the towed receiving acoustic antenna 13 located at the navigation object, from the output of which they are fed to the input of the second M-channel receiver 14. Acoustic signals amplified by the receiver 14 are fed to the blocking input corresponding meters 15 _{m of} propagation time of acoustic signals from pinger beacons to the navigation object, and information about the propagation time in digital form is transmitted in additional Additional blocks 16 _m conversion of time intervals in the distance. The distances calculated in blocks 16 _m go to the calculator 7 coordinates of the navigation object.

Information about the acoustic parameters of the boundary media of the water-seabed interface is preliminarily entered into additional blocks 16 _{m of} conversion of time intervals into distances. Information on the geographical coordinates of the responder beacons and the pinger beacons mechanically associated with them, obtained during the calibration of the navigation system, is previously entered into the coordinate calculator of the navigation object.

Thus, both subsystems, working independently with frequency separation, provide the determination of the coordinates of the navigation object at small and large distances with minimal error.

Information sources

1. Milne P.H. Hydroacoustic positioning systems. L .: Shipbuilding, 1989, p. 49-60.

2. RF patent No. 713278, IPC G 01 S 9/66, 1978 - prototype.

Claims (1)

A long-range hydro-acoustic synchronous long-range navigation system containing a bottom navigation base of M hydroacoustic transponder beacons with different response frequencies f _m (m = 1-M), a clock generator located on the navigation object, an acoustic transmitter with a sampling frequency f ₀ , the input of which is connected a first output generator clock, the M-channel receiver for receiving response signals with frequencies f _m, M gauges propagation time of the acoustic signals to the responder beacon operating at h the frequency of this channel, and vice versa, the first inputs of which are connected to the outputs of the M-channel receiver, and the second inputs are connected to the second output of the clock generator, M × N blocks for converting time intervals to distances in the number N of ray paths, the inputs of which are connected to the outputs of the corresponding propagation time meters, M blocks for selecting the maximum distance value, the inputs of which are connected to the outputs of N blocks for converting time intervals into distances of a given channel, navigation object, the first input of which is connected to the outputs of M blocks for selecting the maximum distance value, characterized in that it includes a second bottom navigation base of M hydro-acoustic pinger beacons with different radiation frequencies F _m (m = 1-M), mechanically connected with the corresponding M beacon transponders containing M synchronously operating clock generators, M transmitters with different operating frequencies F _m , the inputs of which are connected to the outputs of the clock generators, M hydroacoustic emitters with operating frequencies F _m , the inputs of which are connected to the outputs of the transmitters with the corresponding operating frequencies, located on the navigation object is a second clock generator operating synchronously with the clock generators of the pinger beacons, the first output of which is used to synchronize the M synchronous clock generators of the hydroacoustic pinger beacons in front of them installation on the bottom, towed receiving acoustic antenna, a second M-channel receiver for receiving acoustic signals of pinger beacons, the input of which is connected to the output of the towed receiving acoustic antenna, M meters of propagation time of acoustic signals from pinger beacons to the navigation object, the first inputs of which are connected to the outputs of the second M-channel receiver, and the second inputs are connected to the second output of the second clock generator, additional M blocks conversion of time intervals into distances, the inputs of which are connected to the outputs of the M meters of the propagation time of acoustic signals from pinger beacons to the navigation object ii, and the outputs are connected to the second inputs of the coordinate calculator of the navigation object, and M hydroacoustic emitters of pinger beacons and a towed receiving acoustic antenna are located near the seabed at a distance of no more than a wavelength at operating frequencies F _m , and additional M blocks for converting time intervals in distance the required distances r _m are calculated through the measured propagation times t _m according to the formula

where c _P is the propagation velocity of the bottom wave, previously calculated through the parameters of the boundary media of the water-seabed interface according to the formula

where ρ ₁ , с ₁ - density and speed of sound in the bottom layer of water, ρ ₂ , с ₂ - density and speed of sound in the sedimentary layer of the seabed.