JP3438162B2 - Ocean acoustic tomography data analyzer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a received signal peak tracking technique used for data analysis in an ocean acoustic tomography data analyzer.

[0002]

2. Description of the Related Art First, transmission and reception of underwater sound waves in an ocean acoustic tomography system will be described. FIG. 5 is a diagram for explaining transmission and reception of underwater sound waves in the ocean acoustic tomography system. In the example of the ocean acoustic tomography system of FIG. 5, a predetermined sound wave pulse is sequentially transmitted from a single seawater source at regular time intervals (eg, every 3 hours). Then, a single acoustic receiver installed in the sea, for example, about 1000 km away from the sea, receives periodic transmission waves.

On the receiving side, a certain reference time (AM0.0 in the example of FIG. 5) transmitted from the undersea sound source at regular time intervals.
The received wave signal data at the reception time of the transmitted wave of 0) is used as the reference received signal data _Ra, and the received waves of the transmitted waves of other times (AM3.00, AM6.00, ... In the example of FIG. 5) are received. data R ₁ other received signals the received signal data at a wave period, R _2, and ... R _i, performs tracking of each received signal data.

FIG. 6 is a diagram for explaining a propagation path of underwater sound waves and received signal data. FIG. 6 (a) shows the relationship between the depth and the sound velocity. In the ocean, the sound velocity decreases as the depth increases from the sea surface due to the decrease in the water temperature, but about 1000 m.
It is shown that the sound velocity becomes the minimum at the depth of, and the sound velocity increases conversely as the water pressure increases at the deeper.

Further, FIG. 6B shows a state in which a plurality of propagation paths passing through different water depths exist between a single underwater sound source and a single receiving point. Then, a signal group passing through a propagation path having a small amplitude of the propagation depth (difference between the maximum value and the minimum value of the depth) indicated by the tip of the arrow in (b) of FIG. Yes, this signal group has a characteristic that the signal level is high. Also, FIG. 6 (c)
Indicates that the signal group indicated by an arrow near the right end of the received signal data is the signal peak group that propagates the shortest distance the slowest. Each received signal data always has a signal peak group that propagates the latest at this shortest distance.

Conventionally, tracking of received signal data used for data analysis in an ocean acoustic tomography data analysis apparatus (received signal data R _a observed at a certain receiving time which is a reference and observation at other receiving times) A signal tracking process for identifying and associating the signal peaks that may have passed through the same propagation paths with the received signal data group (R ₁ , R ₂ , ... _Ri ). ) Calculates the signal peak density of the signal peak group (see FIGS. 5 and 6) that propagates most slowly at the shortest distance that is always present in the received signal data, and uses the propagation time that maximizes the signal density. Generates the amount of fluctuation between the reference received signal data and the arbitrary received signal data, shifts the reception start time of the received signal data using that amount of fluctuation, and then uses the accumulated data as the reference Received signal data , The signal peaks was intended to determine whether to be tracked.

[0007]

However, in the conventional tracking technology of received signal data used for data analysis in the ocean acoustic tomography system, the signal peak density corresponding to the signal level cannot be calculated, and the peak density maximum However, there is a problem in that it is not possible to calculate an accurate variation amount due to the variation in the time. In addition, since the signal peaks that reach early even after cumulative addition may be split, it is necessary to accurately calculate the signal peak density by some method.

[0008]

The ocean acoustic tomography data analyzing apparatus according to the present invention is a single receiver that is located at a predetermined distance from a sound source and transmits sound waves transmitted from a single undersea sound source at predetermined intervals. In the ocean acoustic tomography data analyzer that has the function of receiving waves and performing peak tracking of the received signal data, each received signal data transmitted from the undersea sound source and received by the receiver is weighted by the distribution function. It is provided with means for calculating new received signal data and means for performing peak tracking processing of the received signal data by using the new received signal data as the received signal data.

[0009]

1 is a block diagram of a received signal tracking system of an ocean acoustic tomography data analyzer according to the present invention. In FIG. 1, reference numeral 1 is a received signal data memory capable of writing and reading data, 2 is a new received signal data memory, 3 is a new received signal data memory, and 4 is the outside of this system and data A data input / output unit 5 for inputting / outputting is an arithmetic processing unit,
The memories 1 to 3, the data input / output unit 4 and the arithmetic processing unit 5 are connected to the bus 6.

Next, the operation of this embodiment will be described. 2 is a flow chart showing the operation of this embodiment, FIG. 3 is a conceptual diagram of received signal data, and FIG. 4 is an explanatory diagram for explaining changes in the results according to this embodiment.
As a result of accumulating the time series of the received signal data as it is in (a) of FIG. 4, (b) of FIG. 4 is obtained by multiplying by the distribution function and shifting by the fluctuation amount obtained by the time of maximum signal peak density, This is a comparison of the cumulative results.

First, the received signal data R _i measured by the ocean acoustic tomography system at regular observation time intervals is input from the data input / output unit 4 to the received signal data memory 1 in sequence for each observation. (S100). The received signal data R _i is, as shown in FIG.
s _i and a received signal series data S _i (t) consisting of a propagation time (msec) between the sound source and the wave receiver and a peak of the sound pressure level.

The received signal sequence data S _i (t) is time-series data in which the propagation time of each peak and the sound pressure level are constituted by numerical values, and t is a relative time from the reception start time. . Here, the subscript i is a serial number (1 to n) given to the received signal data R when the received signal data memory 1 is sequentially input for each observation.

Then, the arithmetic processing section 5 reads the received signal data R _i from the received signal data memory 1, writes the received signal data R _i in the new received signal memory 2, and the received wave written in the new received signal memory 2. The received signal series data S _i (t) is read out from the signal data R _i . Then, the received signal sequence data S
_As shown in the following equation, _i (t) is weighted to each signal peak by the distribution function w (t) to generate a sequence Z _i (t) of newly received signals, The signal series Z _i (t) is written in the new received signal data memory 3 (S101).

[0014]

[Equation 1]

Here, t is the peak time of the signal, θ is the weighting of the signal level of the signal (each signal level / sum of the levels of the received signal data), σ is the smoothing coefficient, and m is the signal sampling time.

Then, the signal peak density is calculated based on the series of new received signals Z _i (t) written in the new received signal data memory 3, and the propagation time that maximizes the signal density is used. Generates the amount of fluctuation between the reference received signal data and the arbitrary received signal data, shifts the reception start time of the received signal data using that amount of fluctuation, and then uses the accumulated data as the reference As the received signal data, it is determined whether or not the signal peak should be tracked.

In this way, the received signal sequence data S _i (t)
The performs weighted calculation to each signal peak in the distribution function w (t), and generates a sequence Z _i (t) of the new received signal, based on the sequence Z _i (t) of the new received signal, The signal peak density is calculated, the amount of variation between the reference received signal data and the arbitrary received signal data is generated using the propagation time that maximizes the signal density, and the amount of variation is used to receive Since the reception start time of the wave signal data is shifted and then accumulated,
As shown in, the signal peak and time of the reference received signal data generated after cumulative addition are clarified, and each signal peak can be tracked more accurately and easily, contributing to the improvement of data analysis accuracy. Is possible.

In this embodiment, the received signal sequence data S _i (t) is weighted to each signal peak by the distribution function w (t), and a new received signal sequence Z _i (t) is calculated. ), The signal peak density is calculated, and the amount of fluctuation between the reference received signal data and any received signal data is generated using the propagation time that maximizes the signal density. It was explained that the reception start time of the received signal data is shifted by using the amount and then accumulated, but the received signal used for the peak tracking processing of the received signal data in the ocean acoustic tomography data analyzer. As the data, the received signal series data S _i (t) is weighted to each signal peak by the distribution function w (t), and a new received signal series Z _i (t) is calculated.
May be applied to any processing.

[0019]

As described above, according to the present invention, each received signal data transmitted from the undersea sound source and received by the receiver is weighted by the distribution function to calculate new received signal data, The received new received signal data is used as the received signal data to perform peak tracking processing of the received signal data, so the signal peak and time of the reference received signal data generated after cumulative addition are clarified. The peaks can be tracked more accurately and easily, which has the effect of contributing to the improvement of data analysis accuracy.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a received signal tracking system of an ocean acoustic tomography data analysis apparatus according to the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment.

FIG. 3 is a conceptual diagram of received signal data.

FIG. 4 is an explanatory diagram for explaining a change in results according to the embodiment.

FIG. 5 is a diagram illustrating transmission and reception of underwater sound waves in the ocean acoustic tomography system.

FIG. 6 is a diagram illustrating a propagation path of underwater sound waves and received signal data.

[Explanation of symbols]

1 Received signal data memory 2 Data memory for newly received signals 3 New received signal data memory 4 Data input / output section 5 Arithmetic processing unit 6 buses

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-197633 (JP, A) JP-A-11-44572 (JP, A) JP-A-10-73659 (JP, A) JP-A-9- 281235 (JP, A) JP 8-304538 (JP, A) JP 10-221445 (JP, A) JP 8-297163 (JP, A) Patent 3395072 (JP, B2) (58) Investigation Areas (Int.Cl. ⁷ , DB name) G01S 3/80-3/86 G01S 5/18-5/30 G01S 7/52-7/64 G01S 15/00-15/96 G01H 5/00 G01H 17 / 00

Claims (2)

(57) [Claims] 1. A function of receiving a sound wave transmitted from a single undersea sound source at predetermined intervals by a single wave receiver located at a predetermined distance from the sound source and performing peak tracking of the received signal data. In the ocean acoustic tomography data analysis device, the received signal data transmitted from the underwater source and received by the receiver is weighted by the distribution function to calculate the new received signal data, and the new received signal data is calculated. An ocean acoustic tomography data analysis device, comprising: means for performing peak tracking processing of received signal data as received signal data. 2. A function of receiving a sound wave transmitted from a single undersea sound source at predetermined intervals by a single receiver located at a predetermined distance from the sound source and performing peak tracking of the received signal data. In the ocean acoustic tomography data analyzer, the received signal data memory in which each received signal data transmitted from the undersea sound source and received by the receiver is written, and the received signal data written in the received signal data memory Based on this, the received signal data is weighted by the distribution function to calculate new received signal data, written in the new received signal data memory, and the new received signal data written in the new received signal data memory is received signal. An ocean acoustic tomography data analysis apparatus, comprising: an arithmetic processing unit that performs peak tracking processing of received signal data as data.