JPS5942465A - Electronic scanning sonar - Google Patents

Abstract

PURPOSE:To eliminate a radio interference, and to execute a display exactly, by making a sound wave emitted to each detecting range have directivity, and emitting it by shifting the time. CONSTITUTION:A sound wave arrival direction finder 8 detects successively an echo from each direction, which is obtained by dividing one detecting range into (n) pieces, from a phase difference of a sound wave inputted to vibfators 5a, 5b. This output is inputted successively to gate circuits 91-9n, respetively. On the other hand, an echo signal amplified by an amplifier 6a is sent to the gate circuits 91-9n , respectively, and only the gate having an output from the sound wave arrival direction detector 8 is opened. Subsequently, an old echo signal stored in a temporary memory 13 is replaced with a new echo signal. The stored echo signal is inputted successively to a picture memory by a memory driving circuit 14, is synthesized, and one picture is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electronic scanning sonar.

Conventional scanning sonar transmits ultrasonic waves with as uniform a sound pressure as possible in both directions within the detection range, and creates images by performing electronic scanning upon reception. Therefore, when projecting a flat seabed, the left and right seabeds are symmetrical and equidistant from the own ship, so echoes will be returned from both sides at the same time, so the record obtained by electronic scanning does not necessarily reflect the true shape of the seafloor. The problem was that it was not displayed.

In order to eliminate the drawbacks of the conventional example described above, the present invention transmits beams with directional characteristics to multiple detection ranges at different times, and scans in multiple divided directions of each detection range at different times. It is characterized by receiving echoes from each direction to form a screen.The purpose is to accurately display the underwater and seabed areas of each detection range because the echoes of different detection ranges are not input at the same time. It provides electronic scanning sonar that can be used. Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing the directivity of the transmitted sound waves according to an embodiment of the present invention. Reference numeral 1.2 indicates a vibrator that emits sound waves 3.4 each having a directivity in two detection ranges. The sound waves 3.4 from the vibrator 1.2 are emitted at different times.

2 and 3 are block diagrams of an electronic scanning sonar according to an embodiment of the present invention, in which 5a and 5b are transducers, 6a and 6b are amplifiers, 7 is an A/D converter, Reference numeral 8 denotes a sonic coming direction detector (phase difference detector), and this sonic coming direction detector 8 is used in the "fish school direction finder" proposed by the present inventors (see Japanese Patent Application No. 71479/1983). One detection range is divided into a plurality of parts and scanned based on the phase difference between the outputs of two vibrators 5a and 5b. 91, 92, . . . , 9n are gate circuits, 10 is a changeover switch, 11 is a comparator, 12 is a counter, 13 is a temporary menu, and 14 is a memory drive circuit.

In the electronic scanning sonar of this embodiment configured as above, the echo signals received by the transducers 5a and 5b are amplified by the amplifiers 6a and 6b, and the sound wave arrival direction detector 8
is input. As described above, this sound wave arrival direction detector 8 detects echoes from each direction in which one detection range (for example, 3 in FIG. are detected sequentially. These outputs are sequentially input to gate circuits 91, 92, . . . , 9n, respectively.

On the other hand, the echo signal amplified by the amplifier 6a is converted into a digital signal by the A/D converter 7, and gate circuits 91 and 92
, .

The echo signal that has passed through the gate circuit 9 is input to a selector switch 10 and a comparator 1, as shown in FIG. The echo signal input to the comparator 11 is compared with the old echo signal stored in the temporary memory 13, and if there is no difference, the changeover switch 10 transfers the echo signal read out from the temporary memory 13 to the old echo signal stored in the temporary memory 13. When there is an output from the comparator 11, the echo signal from the gate circuit 9 is temporarily stored in the memory 13. In addition, the counter 12 sets the number of times the oscillation trigger is fired to the number 1, and stores it in the temporary memory 1 at a rate of once per the number of detection ranges (2 in this embodiment).
3. Replace the old echo signal stored in 3 with the new echo signal. The echo signals stored in the temporary memory 13 are sequentially input to the image memory by the memory drive circuit 14 and synthesized to form one screen. In this way, since the directivity of the sound waves is changed to each detection range and the waves are transmitted at different times, it is possible to scan each detection range separately, and therefore each detection range can be accurately displayed. be able to.

In the description of the above embodiment, there are two detection ranges as shown in FIG. 1, but there may be a plurality of detection ranges.

As explained above, according to the present invention, since the sound waves emitted to each detection range are made to have directionality and are emitted at different times, it is possible to scan each detection range separately. Therefore, there is an advantage that the displayed image is free from interference and can be displayed accurately.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the directivity of a transmitted sound wave according to an embodiment of the present invention, and FIGS. 2 and 3 are block diagrams of an electronic scanning sonar according to an embodiment of the present invention. 1.2... Vibrator, 3.4... Sound wave, 5a, 5b.
...Resonator, 6a, 6b...Amplifier, 7...A/D
Converter, 8...Sound wave arrival direction detector, 91-9n...
・Gate circuit, 10... changeover switch, 11 comparator,
12... Counter, 13... Temporary memory, 14...
・Memory drive circuit. Patent applicant: Keisuke Honta

Claims (1)

[Claims] A beam with directional characteristics is transmitted to multiple detection ranges at different times, and each detection range is scanned in multiple divided directions at different times, and received echoes from each direction are temporarily stored in memory. An electronic scanning sonar characterized in that the outputs of the memories are combined to form one screen.