JPH0295293A - Monitor sonar - Google Patents

Abstract

PURPOSE:To discriminate between an echo from an obstacle and an echo from the sea surface by correcting data of plural successive image planes obtained every time transmission and reception are carried out. CONSTITUTION:A sent signal from a signal generating circuit 1 is power- amplified 2 and applied to some of transmitting and receiving elements of a transmitter receiver 4 so as to generate a sent beam 21, which is sent as an ultrasonic wave into the sea. Reflected light from an obstacle 23 on the sea and the sea surface are received by the transmitter receiver 4 and amplifier 5-1-5-N and noise components are removed 6-1-6-N; and the signals are matched 7 in phase and inputted to an image processing circuit 11 to generate a received beam 22. Then a light-shade image which is obtained every time transmission and reception are performed is converted by an image processing circuit 11 so as to make corrections based upon wake data obtained from a navigation device 12 because the position of a submarine 20 is different and an area in an X-Y plane also varies in scale every time transmission and reception are performed. Then the converted images are superposed and averaged, a wave echo 31, etc., generated at random with time is compressed relatively, and only the obstacle echo 30 is emphasized and displayed 13.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a surveillance sonar, and in particular, to a monitoring sonar that is used to form an image of obstacles when an underwater vessel such as a submarine rises from the sea to the sea using data acquired by sound waves. Regarding surveillance sonar.

[Conventional technology]

Conventionally, this type of surveillance sonar transmits a transmission pulse by forming a transmission beam 21 obliquely upward in the direction of travel of a submersible vessel 20, as shown in FIG. Obstacles 23 on the sea surface received by the delivery beam 22
The intensity of the echoes caused by this and the time required for transmission and reception are measured, and a gradation record is obtained in a display format in which the direct distance calculated based on the measurement results is expressed as a map on a horizontal plane.

FIG. 3 is an explanatory diagram showing a display example of a conventional monitoring sonar. Wave echo 31 on the sea surface is displayed on the display surface 131 of the display 13
At the same time, an obstacle echo 30 is displayed mapped onto a horizontal plane.

[Problem to be solved by the invention]

As shown in the display example in Figure 3, the conventional surveillance sonar described above displays many echoes due to unevenness of the sea surface caused by waves in addition to echoes from obstacles, so depending on the wave situation, A drawback is that it is difficult to distinguish between echoes from obstacles and echoes from the sea surface.

[Means to solve the problem]

The sonar of the present invention is a monitoring sonar that monitors obstacles including ships on the sea by displaying them as images using transmitted and received sound waves when an underwater vessel such as a submersible is surfacing. Correction is applied to a plurality of consecutive predetermined image data obtained in order to eliminate the level difference based on the distance difference between each transmission and reception between the obstacle and the monitoring sonar, and the difference in the transmitted and received beam due to the attitude change of the submersible is corrected. The apparatus is configured to include means for obtaining a display image by superimposing the plurality of image data with the same distance and posture conditions relative to the obstacle by correcting variations in the elevation angle and direction thereof.

〔Example〕

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention, in which a signal generating circuit 1. , a power amplifier that amplifies the power of the transmitted signal 2. N transmitting/receiving switching circuits 3-1 to 3-N for switching between transmitting and receiving, and a transducer 4 having N transmitting/receiving elements.
．． N amplifiers 5-1 to 5-N, N bandpass filters 6-1 to 6-N, and a phasing circuit 7. N detection circuits 8-1 to 8-1 detecting N output beams output from the phasing circuit 7;
8-N, N time/distance conversion circuits 9-1 to 9-1 that receive the outputs of the N detection circuits and convert time data to distance data.
9-N, a depth gauge 10 that provides depth data necessary for conversion processing by N time/distance conversion circuits 9-1 to 9-N; An image processing circuit 119 which receives the outputs of the N time/distance conversion circuits 9-1 to 9-N and processes and outputs them as display image data; a navigation device 12 which provides navigation data necessary for processing by the image processing circuit 11; The intermediate depth gauge 10 and the navigation device 12 are installed on an underwater ship.

Next, the operation of this embodiment will be explained.

The signal generation circuit 1 outputs a transmission signal, and this transmission signal is power amplified by a power amplifier 2, and then a transmission beam 21 shown in FIG. is applied to form an ultrasonic signal and transmitted into the ocean as an ultrasonic signal. Reflected signals from obstacles on the sea and the sea surface are transmitted to the transducer 4.
After receiving the waves and converting them into electrical signals, the signals from the n wave transmitting/receiving elements are amplified by amplifiers 5-1 to 5-N, and noise components are removed by bandpass filters 7-1 to 7-N. Thereafter, the signal is supplied to the electric phase circuit 7 and undergoes phasing processing to form a plurality of transfer beams 22 shown in FIG. The transmission/reception switching circuit 3 switches so that the power amplifier 2 and the transducer 4 are connected when transmitting waves, and the amplifiers 5-1 to 5-N and the transducer 4 are connected when receiving waves.

The signal for each receiving beam output from the phasing circuit 7 is
The waves are detected by the detection circuits 8-1 to 8-N, respectively, and the detected outputs are converted from the slope distance and depth meter 10 corresponding to the time required from transmission to reception by the time/distance conversion circuits 9-1 to 9-N. The provided depth data maps to the X-Y plane in FIG.

From the data for each delivery beam, the image processing circuit 11 creates image data as shown in FIG. 3, for example. FIG. 3 shows the case of sector display, where the radial direction of the sector indicates the distance, and the circumferential direction indicates the direction with respect to the delivery beam. This image data produces images that are reduced or enlarged in response to increases and decreases in the distance between the submersible 20 and the obstacle 23, and even at the same distance, the transmission and reception beam is The directions of the images are crowded, and therefore the amount of shift required for horizontal mapping is also different.

In other words, using the first data of a plurality of consecutive image data as a reference, the image is enlarged or reduced in accordance with the increase or decrease in distance, and then the elevation angle of the transmitting and receiving beam is determined in accordance with the change in attitude state. If the directions are corrected to the same state, n image data for each transmission beam will become image data under the same condition, and by superimposing this, the obstacle echo 30
wave echo '-31 etc. with random probability of occurrence are displayed with n times emphasis, while wave echoes '-31 etc. with random occurrence probability are not accumulated and only those that remain after the superimposition process are displayed, so that S, /
N is significantly improved.

In other words, since the position of the submersible 20 is different for each transmission and reception, the area in the X-Y plane and the scale of the grayscale image obtained for each transmission and reception are different, so the ship track data obtained from the navigation device 12 is Originally, the image processing circuit 11 performs conversion to correct this. In this way, the converted images are superimposed and averaged, and the wave echoes 31 and the like that occur randomly in time are relatively suppressed and only the obstacle echoes 30 are emphasized and displayed on the display 13. .

Note that although the above-mentioned example is based on a case where reception is performed using a preformed beam, it is clear that this reception method can be similarly implemented as other reception methods that satisfy the operational conditions.

〔Effect of the invention〕

As explained above, according to the present invention, images obtained for each transmission/reception performed in a certain sequence are converted into data of the same position state by taking into consideration the position at which each transmission/reception is performed, and these are superimposed. This has the effect of emphasizing echoes from obstacles and simultaneously reducing echoes from the sea surface, making it much easier to detect obstacles.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram showing an example of formation of a transmission and reception beam by a surveillance sonar, and FIG. 3 is an explanatory diagram showing an example of a display by a conventional surveillance sonar.

Claims (1)

[Scope of Claims] In a surveillance sonar that monitors obstacles including ships on the sea by displaying them as images using transmitted and received sound waves when an underwater vessel such as a submarine rises to the surface, every transmission and reception performed at a certain timing Correction is applied to a plurality of consecutive predetermined image data obtained in order to eliminate the level difference based on the distance difference between each transmission and reception between the obstacle and the monitoring sonar, and the difference in the transmitted and received beam due to the attitude change of the submersible is corrected. A surveillance sonar characterized by comprising means for obtaining a display image by superimposing the plurality of image data with the same distance and attitude conditions relative to the obstacle by correcting variations in the angle of elevation and its direction.