JP2982765B2 - Transmission level measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission level measuring apparatus, and more particularly, to an apparatus for measuring a transmission level of a sonar mounted on a ship.

[0002]

2. Description of the Related Art Conventionally, this type of transmission level measuring apparatus has
It is used for measuring the transmission level of the transmitter.

FIG. 4 is a block diagram showing a first example of a conventional transmission level measuring device.

In FIG. 1, a first conventional transmission level measuring apparatus uses a transmitter 12 and a receiver 13 to temporally separate a direct wave and a sea surface reflected wave by a difference in propagation path length. Was sinking deeply. On the transmitting side, the transmitting signal SL (FIG. 5A) formed by the transmitting device 11 is transmitted from the transmitting device 12.

On the measurement side, a signal propagating in water is received by a receiver 13 (received signal RL (FIG. 5B)), and a received level measuring device 14 separates the signal from the sea surface reflected wave in time. The received level RL of the transmitted direct wave is read.
In step 5, the transmission level SL = RL + TL0 is calculated from the input propagation loss value TL0 and the read reception level value RL. The value TL0 of the propagation loss input to the transmission level calculator 15 is obtained by the spherical diffusion calculation formula TL0 = 20logR with respect to the distance R between the transmitter 12 and the receiver 13.

[0006] Japanese Patent Application Laid-Open No. Hei 2-
The transmission level measuring device disclosed in Japanese Patent Application Laid-Open No. 115780 discloses two reception units that receive a target transmission wave existing in water and are arranged apart from each other, and receive the outputs of these two reception units. Two angle measuring circuits for measuring the azimuth angle of the target, a delay amount measuring circuit for measuring a delay amount in reception between the two receiving units, and the output from one of the two receiving units. A reception level measurement circuit for measuring a reception level of a target transmission wave; a distance measurement circuit for measuring a distance to the target based on outputs of the two angle measurement circuits and a delay amount measurement circuit; and a reception level measurement circuit. A transmission level measuring circuit for measuring the target transmission level based on the output and the output of the distance measuring circuit, wherein the target transmission level is measured.

Japanese Patent Laid-Open Publication No. Hei.
The transmission level control method disclosed in Japanese Patent Publication No. 130286 is a transmission level control method in a sonar for optimally controlling the transmission level of a sound wave transmitted into water to a preset transmission level. The level of the sound wave transmitted into the water is controlled based on the deviation obtained by monitoring the level of the sound wave transmitted into the water by frequency analysis and comparing the level with the set transmission level. It is characterized by doing so.

[0008]

However, the transmission level measuring apparatus according to the first conventional example cannot accurately measure the transmission level of a sonar mounted on a ship.

The reason is that when a conventional transmission level measuring device is used at a shallow depth where a sonar mounted on a ship is operated, it is not possible to satisfactorily separate a direct wave and a sea surface reflected wave, This is because a large error occurs in the theoretical calculation formula of the propagation loss.

[0010] The second and third prior arts described above include:
There was a drawback that the number of components was large and complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has been made to solve the above-mentioned drawbacks inherent in the prior art. It is an object of the present invention to provide a novel transmission level measuring device capable of accurately measuring the transmission level.

[0012]

In order to achieve the above object, a transmission level measuring apparatus according to the present invention has a one-element transmitter (1 in FIG. 1) and a controller (3 in FIG. 1). , The single element signal and the beam signal are alternately transmitted, and the reception level measuring device (7 in FIG. 1) reads the level of both the received single element signal and the beam signal, and transmits the signal to the transmission level calculator (7). FIG.
8) is characterized in that the beam transmission level is calculated from the difference between the two levels and the known single element transmission level.

[0013]

According to the present invention, the reception level RLs of the single element signal and the reception level RLb of the beam signal read by the reception level measuring device (7 in FIG. 1) are determined between the transmission level and the propagation loss. Has the following relationship:

RLs = SLs -TL RLb = SLb -TL where SLs is the known single element transmit level, SLb is the beam transmit level, and TL includes all propagation paths between the transmit array and the receiver. Propagation loss.

When the above two equations are subtracted, SLb = RLb−RLs + SLs, the propagation loss term disappears, and only the difference between the beam reception level and the single element reception level and the known single element transmission level are reduced. Remains. That is, to be able to determine the beam transmission level using the value of the propagation loss causing the error,
It is possible to accurately measure the transmission level of a sonar at a shallow depth where time separation between a direct wave and a sea surface reflected wave is difficult.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described in detail with reference to FIG.

FIG. 1 is a block diagram showing an embodiment according to the present invention.

First, the configuration will be described. Referring to FIG. 1, the transmission level measuring apparatus according to the present invention is divided into a sonar side for forming a signal and transmitting the signal into water, and a measuring side for receiving and processing a sound wave transmitted through the water. Since the sonar side is generally mounted on a ship, the sound wave transmission depth is shallow near the sea surface. In addition, the distance between the sonar side and the measurement side is long enough to form a transmission beam.

On the sonar side, the one-element transmitter 1 forms a single-element output transmission signal, and the beam transmitter 2 forms a beam-output transmission signal. The controller 3 forms a transmission pattern of the single element signal and the beam signal, and controls the changeover switch 4. The changeover switch 4 switches the connection between the one-element transmitter 1 and the beam transmitter 2 under the control of the controller 3. The transmission array 5 has a structure in which a single element is arranged, and transmits a signal transmitted by the connection between the changeover switch 4 and the transmitter into water.

On the measurement side, the receiver 6 receives a sound wave that has propagated in water. The reception level measuring device 7 connected to the receiver 6 detects a signal from the received sound wave and reads the reception level. The transmission level calculator 8 connected to the reception level measuring device 7 calculates and outputs the beam transmission level from the read reception level and the known single element transmission level.

Next, the operation will be described. In the one-element transmitter 1, an output signal from a single element constituting the transmission array 5 is formed. In the beam transmitter 2, the transmission array 5
A beam output signal to be synthesized is formed by phasing the plurality of element outputs. These output signals are generally pulse signals. In the controller 3, the transmission arrangement and timing of the single element signal and the beam signal are formed and output to the changeover switch 4.

The changeover switch 4 switches the connection between the output of the one-element transmitter 1 and the output of the beam transmitter 2 in accordance with the above arrangement and timing. The formed signal is output from the transmitter connected to the changeover switch 4. The output signal is transmitted underwater by the transmission array 5.

FIGS. 2A and 2B are diagrams showing a relationship between a received signal and a transmitted signal in one embodiment of the present invention. The transmission signal patterns shown in FIGS. 2A and 2B are as follows.
This is an example in which an arrangement and timing for transmitting a single element signal and a beam signal alternately at equal intervals are output.

The transmission level SLs of the single element signal is known, and the transmission level SLb of the beam signal is the transmission level measured by the transmission level measuring device of the present invention.

In general, a signal transmitted from the transmission array 5 installed at a shallow depth repeats sea surface reflection and reaches a receiver 6 installed at a long distance through many propagation paths. Therefore, the signal received by the receiver 6 is a signal obtained by superimposing them, and the direct wave cannot be time-separated, and does not match the theoretical calculation formula of the spherical diffusion.

The signal received by the receiver 6 is output to a reception level measuring device 7. After the single-element signal and the beam signal are detected by the reception measuring device 7, the reception level RLs of the single-element signal and the reception level RLb of the beam signal are read and output to the transmission level calculator 8. The transmission level calculator 8 calculates the beam transmission level SLb = RLb-R from the single element reception level RLs, the beam reception level RLb, and the single element transmission level SLs input as known information.
Ls + SLs is calculated and output.

That is, the single element transmission level SLs causes a propagation loss TL and is received at the single element reception level RLs,
SLs−TL = RLs, and the beam transmission level SLb
Generates a propagation loss TL and is received at the beam receiving level RLb, and SLb−TL = RLb. Since the term of the propagation loss TL disappears from the subtraction of both equations, the input RLs, R
SLb is determined from only the values of Lb and SLs. Thus, it is possible to accurately measure the transmission level of the sonar without using the theoretically calculated value of the propagation loss that causes the error.
FIGS. 3A and 3B are diagrams showing the relationship between received signals corresponding to transmitted signals in another embodiment of the present invention. FIG.
Referring to (a) and (b), in another embodiment of the present invention, the changeover switch 4 controls two outputs of the single element transmission signal generated from the one element transmitter 1 and the beam transmission. And two outputs of the beam transmission signal generated from the transmitter 2 are alternately output. As an alternative, it is a matter of course that three signals may be alternately output.

[0028]

As described above, the transmission level measuring apparatus according to the present invention can accurately measure the transmission level of a sonar mounted on a ship.

The reason is that the transmission level can be obtained without using the theoretically calculated value of the propagation loss which causes an error.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a transmission level measuring apparatus according to the present invention.

FIGS. 2A and 2B are diagrams showing a relationship between a received signal and a transmitted signal according to an embodiment of the present invention.

FIGS. 3A and 3B are diagrams showing a relationship between a received signal and a transmitted signal in another embodiment of the present invention.

FIG. 4 is a block diagram showing a conventional transmission level measuring device.

FIGS. 5A and 5B are diagrams showing a relationship between a received signal and a transmitted signal in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... One element transmitter 2 ... Beam transmitter 3 ... Controller 4 ... Changeover switch 5 ... Transmitting array 6 ... Receiver 7 ... Receiving level measuring device 8 ... Transmitting level calculator

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-113616 (JP, A) JP-A-4-110788 (JP, A) Jpn. Translated by Akira Tsuchiya, supervised by Minoru Nishimura, "Principles of Underwater Acoustics", Kyoritsu Shuppan Co., Ltd., first published on December 1, 1978, p. 43-P. 49 (58) Field surveyed (Int.Cl. ⁶ , DB name) G01S 3/80-3/86 G01S 5/18-5/30 G01S 7/52-7/64 G01S 15/00-15/96

Claims (4)

(57) [Claims] 1. A sonar side transmits a single element transmission signal of a known transmission level and a beam transmission signal of an unknown transmission level alternately, and is arranged at a distant point. Transmitting level measurement characterized by measuring the transmitting level of the unknown beam transmitting signal by comparing the level of the single element transmitting signal and the level of the beam transmitting signal received on the measurement side. apparatus. 2. A single element transmitter for forming a single element transmission signal, a beam transmitter for forming a beam transmission signal,
A changeover switch for switching between the output of the single element transmitter and the output of the beam transmitter; a controller for controlling the changeover switch; and the single element transmission signal or the beam transmission output from the changeover switch. A wave transmitting array for transmitting a wave signal into water, a wave receiving device for receiving the wave transmitting signal transmitted through the water, and a single element transmitting signal and a beam transmitting signal receiving from the received signal. A reception level measuring device for reading a level; and a transmission level calculator for calculating and outputting a beam transmission level from the single element reception level, the beam reception level, and the known single element transmission level. A transmission level measuring device, characterized in that: 3. The apparatus according to claim 2, wherein the changeover switch alternately switches between a single element transmission signal output from the single element transmitter and a beam transmission signal output from the beam transmitter. The transmission level measuring device according to claim 2. 4. The switch according to claim 1, wherein a plurality of outputs of the single element transmission signal output from the single element transmitter and a plurality of outputs of the beam transmission signal output from the beam transmitter are provided. 3. The transmission level measuring device according to claim 2, further comprising: alternately switching and outputting.