JPH05346462A - Underwater acoustic simulation equipment - Google Patents

Abstract

PURPOSE:To obtain underwater acoustic silulation equipment which can execute a high-speed arithmetic processing by saving energy of computation and by making the computation efficient, in the underwater acoustic simulation equipment generating an underwater acoustic simulation signal in a sonar system of an underwater running body. CONSTITUTION:Correlative phase computation for each vibrator 02 and underwater acoustic waveform computation not containing phase information among vibrators are executed separately from each other, and a correlative phase is given by a random number in compliance with a Rician distribution, while an offset value of the Rician distribution is determined by the position and the direction of an underwater acoustic source. By synthesizing the result of the correlative phase computation for each vibrator 02 with the result of the underwater acoustic waveform computation not containing the correlative phase information on each vibrator, an underwater acoustic signal for each vibrator is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater acoustic simulation apparatus for generating a simulated underwater acoustic signal in a sonar system for underwater vehicles.

[0002]

2. Description of the Related Art FIG. 1 schematically shows a sonar system for underwater vehicles. As shown in the figure, underwater sound is
The pressure wave in the water is converted into an electric signal through the plurality of vibrators 02 provided in 1. The vibrator 02 is used as an electroacoustic transducer that outputs an acoustic signal into water or receives an acoustic signal in water. The oscillators 02 are arranged vertically and horizontally in a plane as shown in FIG. 2, for example.

The underwater sound converted into an electric signal is amplified and beam-synthesized by the receiver 03. What is beam synthesis?
The phase shift and weighting are applied to the output from each transducer 02 to form a signal having a directional characteristic. The underwater sound after beam formation is input to the signal processor 04, and various signal processes such as filtering are performed.

Conventionally, in the case of evaluating the response of the sonar system by simulating the underwater sound with respect to the sonar system of such an underwater vehicle, a simulated signal corresponding to beam synthesis is input to the signal processor 04. ..

A calculation algorithm for generating the simulated signal is shown in FIG. As shown in FIG.
, A random number according to the Rayleigh distribution is generated to randomize the reverberation waveform, and the processor 2 calculates the level of reverberation (volume, sea surface, seabed) and the correlation phase of each beam, and further synthesizes them by the processor 3. The reverberation waveform is calculated and output. Reverberation refers to continuous observation mainly by the active sonar at the sound receiving point where there is sound scattered mainly by the sea surface, the sea floor, or the underwater scatterer.

FIG. 4 shows a calculation time chart. As shown in the figure, each processor 1, 2, 3
The calculation of the second time, the third time ... Is repeated,
The calculation cycle t _s is several tens of msec at the maximum.

[0007]

In recent years, as a new technology of a sonar system, adapter beamforming (abbreviated as ABF) which generates an acoustic signal having arbitrary directivity with respect to underwater acoustic input to an oscillator. Is being developed.

However, in the above-described conventional simulation method, since the simulation signal corresponding to the beam is input to the signal processor 04, it is not possible to simulate the adapter beamforming which is such a new sonar system. ..
Therefore, a simulation method of inputting a simulation signal corresponding to the oscillator 02 to the receiver 03 is being studied.

However, since it is necessary to consider the correlation phase of the oscillator 02, this simulation method is expected to require a calculation amount that is about 10 times that of the above simulation method.
Therefore, in this simulation method, high-speed arithmetic processing has been an important issue.

The present invention has been made in view of the above prior art, and an object of the present invention is to provide an underwater acoustic simulation apparatus capable of performing high-speed arithmetic processing by saving labor and efficiency of calculation. It is a thing.

[0011]

In order to achieve the above object, the present invention employs the following means. (1) The calculation is divided into the correlation phase calculation of each transducer and the underwater acoustic waveform calculation that does not include the phase information between the transducers. (2) The correlation phase is given by a random number that follows the Rician distribution (offset Gaussian distribution). The offset value of the Rician distribution is determined by the sound source position and direction of the underwater sound. (3) The correlation phase calculation result of each transducer and the underwater acoustic waveform calculation result that does not include the correlation phase information of each transducer are combined to generate the underwater acoustic signal of each transducer.

[0012]

In the present invention, in order to save the calculation labor, it is considered that the vibrators have the same directional characteristics, and the waveform calculation of the underwater sound is made common. As a result, the amount of calculation is reduced to 1 / number of transducers, as compared with the case where calculation is performed as it is. In order to improve the efficiency of the calculation, a parallel calculation algorithm that performs the reverberation level calculation and the correlation phase calculation for each transducer independently is used, and parallel calculation is enabled.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. FIG. 5 shows an embodiment of the present invention. As shown in the figure, the processor 1 generates random numbers according to the Rayleigh distribution to randomize the reverberation waveform, and the processor 2 calculates the level of reverberation (volume, sea surface, sea bottom) and the correlation phase of each beam, and further, The processor 3 synthesizes them and calculates the reverberation waveform. That is, the reverberation waveform common to each transducer is calculated by the processors 1, 2, and 3.

On the other hand, the processor 4 calculates the correlation phase offset amount for each transducer, the processor 5 generates a Gaussian random number, and the processor 6 synthesizes them to generate a Rician distributed random number. That is, the processors 4, 5 and 6 calculate the correlation phase between the transducers.

Further, the processor 7 synthesizes the output of the processor 3 and the output of the processor 6 and calculates the phase shift for each transducer. That is, the processor 7 synthesizes the reverberation waveform and the correlation phase to generate a simulated signal of the reverberation waveform of each transducer. The processor 7 synthesizes the reverberation waveform and the correlation phase as shown in the following equation. S _i (t) = R _V (t) exp (j (θ _i (δ _v (t)))) + R _s (t) exp (j (θ _i (δ _s (t)))) + R _B (t ) Exp (j (θ _i (δ _B (t)))) where S _i : Reverberation waveform simulated signal of the i-th oscillator θ _i : Phase generation function R _V , R of the Riian distribution of the i-th oscillator _s, R _B: volume, sea level, the complex waveform of the reverberation of the seabed _{δ v (t), δ s} (t), δ B (t): offset value Rician distribution (determined by the sound source position and orientation.)

FIG. 6 shows a calculation time chart. As shown in the figure, the reverberation level calculation by the processors 1, 2, 3 and the correlation phase calculation of each transducer by the processors 4, 5, 6 are performed independently and in parallel. Therefore, the efficiency of calculation is improved, and the calculation cycle t _s is relatively short.

The simulated signal generated in this manner corresponds to the oscillator, and by inputting to the receiver 03 shown in FIG. 1, it becomes possible to simulate the sonar system by adapter beamforming.

As described above, in the present embodiment, in order to save the calculation labor, it is considered that the vibrators have the same directional characteristics, and the waveform calculation of the underwater sound is made common. As a result, the amount of calculation is reduced to 1 / number of transducers, as compared with the case where calculation is performed as it is. In addition, as a calculation efficiency, a parallel calculation algorithm that performs the reverberation level calculation and the correlation phase calculation of each transducer independently has been made possible.

[0019]

As described above in detail based on the embodiments, the present invention makes it possible to generate a simulated signal of underwater acoustic corresponding to the new technology of the sonar system, and the range of the function evaluation of the underwater vehicle. Has expanded.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a sonar system.

FIG. 2 is an explanatory diagram showing an array of transducers.

FIG. 3 is an explanatory diagram showing a conventional calculation algorithm.

FIG. 4 is a conventional calculation time chart.

FIG. 5 is an explanatory diagram showing a calculation algorithm according to an embodiment of the present invention.

FIG. 6 is a calculation time chart according to an embodiment of the present invention.

[Explanation of symbols]

 1,2,3,4,5,6,7 Processor 01 Receiver 02 Transducer 03 Receiver 04 Signal Processor

Claims (1)

[Claims] 1. A correlation phase calculation for each transducer and a hydroacoustic waveform calculation that does not include phase information between the transducers are performed separately, and the correlation phase is given by a random number according to the Rician distribution, and the offset of the Rician distribution is calculated. The value is determined by the sound source position and direction of the underwater sound, and the correlation phase calculation result of each transducer and the underwater acoustic waveform calculation result that does not include the correlation phase information of each transducer are combined, and each transducer is calculated. An underwater acoustic simulator that generates the underwater acoustic signal.