RU2032187C1 - Sonar synchronous range-finding navigation system - Google Patents

Abstract

FIELD: sonar systems. SUBSTANCE: sonar system has bottom navigation base of M-sonar transponders with different frequencies of response and the following components arranged on navigation object: sonar transmitter, synchronizing pulse generator, M-channel receiver, M-number of time meters of propagation of sonar signals to transponders and backward, M.N-number of units converting the time intervals into ranges, N-number in each of M-channels, M-number of maximum distance selection units from N-number of magnitudes and navigation object coordinates computer. Introduced in each of M-channels according to the number of N-beams are trajectories of N-1 additional time meters of sonar signal propagation, N-1 delay multivibrators, N-1 gate pulse multivibrators and N-1 selectors. Besides that, N(N-1) additional units for converting the time intervals into ranges, N-1 additional units for selecting the maximum magnitude of range and range averager are introduced in each of M-channels. EFFECT: enhanced reliability. 2 dwg

Description

 The invention relates to sonar and can be used in the development of sonar navigation systems of high accuracy, operating in the presence of reflecting interfaces, i.e. under waveguide propagation conditions.

Known sonar rangefinder navigation system [1], consisting of M sonar beacons-transponders installed in the area of operation of the navigation object and located on the site of the sonar transmitter, interrogating beacons-responders at a frequency f _o , M-channel receiver that receives responses from beacons-responders to frequencies f ₁ , f ₂ , ..., f _m , and a position calculator of the navigation object.

 In a rangefinder navigation system of this type, the coordinates are determined by a set of distances, each of which is determined through the measured response delay time t according to the formula r = Ct / 2, where: C is the average speed of sound for a given area of work.

 The disadvantage of such a navigation system is the large error in determining the coordinates associated with the inconstancy of the speed of sound in a real marine environment, as well as with the multipath phenomenon of sound propagation in the presence of reflecting interfaces.

 Closest to the proposed technical solution is a hydroacoustic navigation system [2], containing a bottom navigation base of M hydroacoustic transponders with different response frequencies and a hydroacoustic transmitter located at 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 the M meters of the propagation time of hydroacoustic signals to a transponder operating at the frequency of this channel and vice versa the input inputs of which are connected to the output of the clock generator, N (by the number of types of possible ray paths in each of the M channels) of the blocks for converting time intervals into distances, the inputs of which are connected to the output of the propagation time meter of the corresponding channel, and the unit for selecting the maximum distance value, the input of which connected to the outputs of N blocks for converting time intervals in the distance of a given channel, and the outputs of blocks for selecting the maximum distance value of all M channels are connected to the inputs I coordinate the navigation object.

 The inclusion in the navigation system of N blocks of conversion of the measured time intervals in the distance in each of the receiving channels allows one to take into account, within the framework of some calculation model, for example, the ray refraction associated with the inconstancy of the speed of sound, as well as the multipath propagation process associated with the presence of reflecting section boundaries.

 A disadvantage of such a navigation system is also a sufficiently large error in determining the coordinates, due to the fact that only part of the information about the time of arrival of the signal, namely, its leading edge, and also with a certain probability of interference in the receiving channel, which is perceived as useful signal if its arrival time is less than the arrival time of the 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 differs from the real one, which ultimately will lead to an uncontrolled error in determining the coordinates of the object.

 The purpose of the invention is to develop such a sonar synchronous rangefinder navigation system that allows to reduce the error in determining the coordinates of the navigation object.

 For this, in a hydroacoustic synchronous rangefinder navigation system containing a bottom navigation base of M hydroacoustic transponders with different response frequencies and a hydroacoustic transmitter, a clock generator, an M-channel receiver, M measuring instruments for the propagation time of hydroacoustic signals to and from transponders, M˙ N blocks for converting time intervals in the distance by N in each of the M channels, M blocks for selecting the maximum distance values from N s The values and the coordinate calculator of the navigation object are introduced into each of the M channels N-1 of additional propagation time meters, N-1 delay multivibrators, N-1 strobe multivibrators, N-1 selectors, the first inputs of N-1 propagation time meters with the output of the clock generator, the second inputs are connected to the first outputs of the corresponding selectors, and the outputs are with N˙M inputs of the unit for converting time intervals to distances, the first input of each of the selectors is connected to the output of the corresponding about the strobe multivibrator, the second input is with 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 input of each subsequent delay multivibrator is connected to the second output of the corresponding selector.

 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 a distance averager are introduced into each of the M channels, the inputs of each of the N-1 sets of N blocks conversions of time intervals in the distance are connected to the corresponding outputs N-1 of additional time interval meters, and the outputs are connected to the inputs of N-1 blocks for selecting the maximum value, the outputs of all blocks for selecting the maximum value are connected to N inputs distance meter, and the output of the distance averager is connected to the input of the coordinates calculator of the navigation object.

Such a design of a hydroacoustic synchronous rangefinder navigation system allowed the receiver to receive a series of pulses during multipath signal propagation, each of which corresponds to one of the possible ray paths, and each of the measured arrival times of these pulses t _{i, n} can be used to determine the desired distance. This redundancy of information is used to reduce the error in determining the distance and coordinates of the navigation object.

раз в сравнении с прототипом.So, for example, when using N pulses corresponding to different ray paths, the error in determining the distance decreases in

times in comparison with the prototype.

If the interference channel preceding the appearance of the useful signal gets into the receiving channel, it also causes a false alarm, however, for the next N-1 cycles of selecting the useful signal, it will be accepted by the selector and N-1 value of the measured arrival times t _{i, n} will be used to determine the desired distance. When averaging the entire set of N measured distances by averager 12 _{i, the} specific gravity of one erroneous measurement will be significantly reduced, and the error in measuring the distance in the presence of interference will be reduced by N times.

In order for the useful signal to fall into the selection interval τ ₁ after the interference arrives, its duration should be equal to the maximum expected useful signal arrival time t _max , increased by the signal broadening time due to dispersion
τ ₁ = t _max (1 + Δ C / C); Δ C = C _gr - C, where: C is the speed of sound in the medium; With _gr - the speed of sound in the ground.

 Thus, the proposed navigation system in a new set of essential features in its characteristics exceeds the prior art similar analogous navigation systems, and the set of essential features of the invention has a causal relationship with the achieved technical result.

 In FIG. 1 is a structural diagram of a navigation system; in FIG. 2 shows the temporal relationships between the received signals and the operation of the time selectors.

In FIG. 1, 2 shows transponders 1, i of the i-th channel, i = 1 - M; transmitter 2 acoustic impulses; M-channel receiver 3; block 4 _i measuring the propagation times of hydroacoustic signals; meter 4 _{i, n of} the propagation time of the n pulse in the i-th channel, n = 1 - N; multivibrator 5 _iK delay of the i-th channel, K = 1 - (N - 1); multivibrator 6 _{i, k} strobe-pulse of the i-th channel, K = 1 - (N - 1); selector 7 _{i, K of the} i-th channel, K = 1 - (N - 1); block 8 _{i, n of} selecting maximum values in the i-th channel, n = 1 - N; block 9 converting time intervals in the distance of the i-th channel; block 9 _i (n, n ') converting the time interval into the distance for the ray path n', n = 1 - N, n '= 1 - N; calculator 10 coordinates of the object; generator 11 clock pulses; averager 12 _i distances.

 The system operates as follows.

Clock generator 11 triggers the transmitter 2 resets the acoustic pulses and ^M. N meters 4 _{i, n} (i = 1 - M, n = 1 - N) of the propagation time of hydroacoustic signals to transponders.

At the time of starting, the transmitter 2 emits an acoustic request signal at a frequency f _o , which, propagating in the aquatic environment, is received by transponders 1 _i (i = 1 - M). Each of the transponders emits an acoustic response signal at a frequency f _i (i = 1 - M) at the time of the arrival of a request signal to it. The signals emitted by transponders, propagating in water, are received by an M-channel receiver of 3 sonar signals. Each of the channels of the receiver 3 _{i is} tuned to one of the frequencies f ₁ and receives a response signal emitted by the corresponding transponder 1 _i . The signals amplified and detected in the receiver from the output of each channel go to block 4 _{i for} measuring the propagation time of hydroacoustic signals.

The signal from the first output of the ith channel of the receiver 3 _{i is} fed to the locking input of the time meter 4 _{i, 1} and the integrator locks it with its leading edge from the time stamp pulses of the clock generator 11 at the time t _{i, 1} (Fig. 2). At the moment the next synchronizing pulse is generated by the generator 11 clock pulses, information is transmitted in the digital code on the number of time stamps counted (accumulated) by the time meter 4 _{i, 1} , which characterizes the propagation time of the signal from the navigation object to the corresponding transponder and vice versa along the shortest path of N beam trajectories from the first integrator to the first N blocks 9 _i (1, n ') (n' = 1 - N) transforming the time interval t _{i, 1} in the distance τ _i , 1n '. Different transformation units 9 _i (1, n ') corresponding to different n' transform the time interval t _{i, 1} into N different distances corresponding to different types of ray paths, each of which is characterized by the number of inversion points or reflections from the interface. The distance values found in the conversion units 9 _i (1, n ') N of the distances τ _{i, n'} are fed to the inputs of the unit for selecting the maximum distance values 8 _{i, 1} , from the output of which the maximum distance value is supplied to the first input of the averager 12 _i distances.

The signal from the second output of the ith channel of the receiver 3 _{i is} fed to the input of the delay multivibrator 5 _{i, 1} , which, when opened, generates a delay pulse, the duration of which is equal to the duration of the emitted signal τ. The trailing edge of this pulse is opened by the multivibrator of the strobe pulse 6 _{i, 1} , which, when opened, generates a pulse whose duration τ ₁ is determined in advance taking into account the maximum broadening of the working signal during its propagation due to multipath. A strobe pulse of duration τ arrives at the first input of the selector 7 _{i, 1} and opens it. When a useful signal arrives from the third output of the ith channel of the receiver to the second input of the selector 7 _{i, 1,} that part of the useful signal that lies in the selection interval τ ₁ will appear on its output, and the useful signal from the first output of the selector 7 _{i, 1 is} fed to the locking input of the meter 4 _{i, 2 of} the propagation time and locks it at time t _{i, 2} (Fig. 2), and from the second output to the input of the delay multivibrator 5 _{i, 2} and opens it for a time τ. The trailing edge of the delay multivibrator pulse 5 _{i, 2} opens the multivibrator of the strobe pulse, while the process of selecting the remaining part of the useful signal N times by the number of selectable possible ray paths and the corresponding propagation times t _{i, n,} n = 1 - N.

All measured propagation times t _{i, n} are supplied to the inputs of the corresponding blocks for converting time intervals to distances 9 _i (n, n '), in which each value t _{i, n is} converted into a set of possible distances τ _{i, n n'} (n '= 1 - N), the values of which go to the inputs of the corresponding blocks for choosing the maximum values of 8 _{i, n} , from the outputs of which all the maximum values of the distances τ _{i, n} (n = 1 - N) go to the corresponding inputs of the averager 12 _{i of the} distances.

From the outputs of the distance averagers 12 _{i, the} found values of the average distances go to the input of the calculator 10 coordinates of the navigation object.

Claims (1)

 A HYDRO-ACOUSTIC SYNCHRONOUS LONG-DIMENSIONAL NAVIGATION SYSTEM containing a bottom navigation base of M hydroacoustic transponders with different response frequencies and a hydroacoustic transmitter, a clock generator, an M-channel receiver, M measuring instruments for the propagation time of hydroacoustic signals from the receiver to the receiver, M time intervals in a distance of N in each of the M channels, M blocks for selecting the maximum distance value from N values and subtracting a coordinate remover of the navigation object, characterized in that, in each of the M channels, according to the number of ray 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, the first the inputs of N - 1 propagation time 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 N · M inputs of the time interval to of the station, the first input of each of the selectors is connected to the output of the corresponding multivibrator of the strobe pulse, the second input is connected to the output of the corresponding channel of the receiver, the input of the first delay multivibrator is connected to the output of the corresponding channel of the receiver, and the output of each subsequent delay multivibrator is connected to the second output of the corresponding selector, in each of the M channels introduced N (N - 1) additional blocks for converting time intervals in distance, N - 1 additional blocks for selecting the maximum value distance and averager, moreover, the inputs of each of N - 1 sets of N blocks for converting time intervals into distances are connected to the corresponding outputs of N - 1 additional meters of time intervals, and the outputs are connected to the inputs of N - 1 additional blocks for selecting the maximum value, the outputs of all blocks for selecting the maximum distance value 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.

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