JPS60115884A - Ultrasonic detecting method - Google Patents

Abstract

PURPOSE:To shorten a search time by switching elevation angles at time intervals corresponding to transmit pulse width, transmitting a wave in plural elevation directions successively, and performing signal processing at every elevation angle by a reception system. CONSTITUTION:A generator 10 sends an azimuth scanning signal to a generator 9 on the basis of a time base signal from a generator 11 to generate a pulse signal for operating the transmitter 4 and an elevation angle signal. Simultaneously, the elevation angle signal is applied to a transmitter 4 from a generator 7 to obtain an elevation angle theta1 at time corresponding to a transmit wave pulse 2 and an elevation angle theta2 at time corresponding to a transmit wave pulse 3, and a transmit signal is supplied to a transmitter receiver 6. Then, a reflected acoustic wave from a target is applied to phase shifting receivers 8 and 8' and an azimuth scan is made by azimuth scanning circuits 12 and 12' and the generator 10 to obtain a signal in the direction of the elevation angle theta1 at a terminal 14 and a signal in the direction of the elevation angle theta2 at a terminal 15, thereby displaying them.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to the improvement of detection capability in scanning sonar.
This concerns the second issue.

(Technical Background) In the current fishing industry, many fishing boats are equipped with scanning sonar, and by making full use of this, they are achieving dramatic fishing effects compared to the past. Furthermore, even methods that have made dramatic advances over the past cannot be completely foolproof, and if this method becomes widespread, it will be possible to use it even faster and more accurately based on the current method. You will come to appreciate the methods and devices that make it possible to discover seafood.

(Prior art and problems) Conventional scanning sonar transmits waves in a conical pattern with a constant depression angle and a constant thickness below the sea surface, and is reflected from schools of fish. The incoming sound waves are received by a receiving pattern on a pencil beam that rotates in the direction of the cone at high speed.

Schools of fish are detected by changing the angle of depression, that is, by sequentially changing the angle at which the cone expands.

Therefore, the search is carried out at the given depression angle, and then the search is carried out by slightly changing the depression angle, which is repeated, and the searchable range is searched, which is disadvantageous in that it takes a lot of time. Also, if fish shadows appear faintly on the CRT display at a certain depression angle, you can check whether most of the fish are present at shallower or deeper depths than the current depression angle. You have to try changing the angle of depression of the sound wave beam upward or downward, but if you change the angle of depression to the direction where the school of fish is conveniently located, you can reliably capture the school of fish in a short time. If you change the angle of depression in the opposite direction, you have to try pulling back again. In the case of fish species with slow swimming speeds, even if such wasted time is spent, it is unlikely that the school of fish will be missed, but in the case of fish species with fast swimming speeds such as tuna, time The disadvantage is that there are many cases where you can get away with it while you are wasting it.

(Object of the present invention) In view of the above-mentioned drawbacks of the conventional scanning sonar, an object of the present invention is to provide a detection method that shortens the time required to search for a school of fish using a scanning sonar.

(Configuration of the Invention) In order to achieve the above object, the present invention has the following 31 configurations. In other words, in the Suki A ning sonar,
The wave transmission time for each repetition cycle 1lII is divided into the number of companies, and pulsed sound waves are sequentially transmitted to different depression angles corresponding to each divided time, and the waves are reflected from the target object and received. The ultrasonic detection method is characterized in that the received signal of the sound wave is subjected to azimuth scanning and received signal processing for each of the different angles of depression, and is displayed for each angle of depression.

(Example of the invention) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing transmission pulses when the present invention is applied. For convenience of explanation, the case of classification 1-2 will now be explained as an example. 1 indicates the entire transmitted pulse.

2.3 are the transmission pulses of each divided portion, the transmission pulse 2 is transmitted at an angle of depression, and the transmission pulse 3 is transmitted at an angle of depression θ2. T is the repetition period of wave transmission.

FIG. 2 is a diagram showing the configuration of an embodiment of a transmitting/receiving system and a transmitted beam from a transducer to which the present invention is applied. 4
is a transmitter, 5 is a transmission/reception switching circuit, 6 is a transducer, 7 is an angle of depression signal generator, 8.8' is a phase shift receiver, 9 is a distance signal generator, 10 is an azimuth scanning signal generator, 11 is a Time base generator, 12, +2' is an azimuth scanning circuit, 13 is a distance signal output terminal, ! 4 is a received signal output terminal at depression angle θ1, 1
5 is a received signal output terminal at the depression angle θ2.

The operation of this embodiment will be explained below.

First, the time base signal from the time base generator 11 is applied to the azimuth scanning signal generator lO, and the azimuth scanning signal is sent from the azimuth scanning signal generator 10 to the distance signal generator 9, where the transmitter 4 and the angle of depression A pulse signal is generated having a significant repetition period for operating the signal. At the same time, a depression angle signal is applied to the transmitter 4 from the depression angle signal generator 7, and at a time corresponding to transmission pulse 2, a depression angle signal such that the depression angle becomes 01 is added, which corresponds to transmission pulse 3. A depression angle signal such that the depression angle becomes 02 is added to the time. The transmission signal generated in this way is sent to the transmission/reception switch 6
The wave is applied to the transducer 6 via the waveguide, and is first transmitted at an angle of depression θ, and then transmitted at an angle of depression θ2. The transmitted sound waves hit the target object and were reflected and returned to the transducer 6, where they are converted into electrical signals, passed through the transceiver switch 5, and sent to the phase shift receivers 8 and 8'. can be added in the same way. On the other hand, a depression angle signal is applied to the phase shift receiver 8 from the depression angle signal generator 7 so that only the received signal due to the sound wave reflected from the direction of the depression angle θl is extracted, and the phase shift receiver 8' A depression angle signal is added from the depression angle signal generator 7 so that only the received signal due to the sound wave reflected and returned from the direction of the depression angle θ2 is extracted.

Next, the output signal of the phase-shifting receiver 8 is sent to the azimuth scanning circuit 12, and the output signal of the phase-shifting receiver 8' is sent to the direction scanning circuit 1;
2'. The azimuth scanning circuits 12 and 12' include:
Azimuth scanning signals are applied from the azimuth scanning signal generator 10 to perform azimuth scanning. In this way, a received signal from a direction where the angle of depression is 01 appears at the output terminal 14, and a received signal from a direction where the angle of depression is 0□ appears at the output terminal 15.

The received signals for each depression angle thus obtained are displayed on a display as shown in FIGS. 3(a) and 3(b), for example.

In FIG. 3A, for example, the display unit 16 displays a received image with an angle of depression of θ, and the display unit 17 displays a received image with an angle of depression of 02.

FIG. 2B shows a case where the display unit 18 displays received images for both depression angles of 01 and 02 in a superimposed manner, and the display unit 19 displays cross-sectional images for each depression angle.

As can be seen from FIG. 1, although the depression angles θ1 and 02 differ by the time equivalent to the pulse width in the transmission pulse time, a distance error that would impede angle group detection does not occur and is not a problem.

(Effects of the Invention) As explained above, although there is a difference in time due to the transmission pulse width, the depression angle is instantly switched and waves are transmitted sequentially in multiple depression angle directions, and the receiving system receives signals for each depression angle. Because processing is performed, it has the advantage of providing the same effect as searching for schools of fish using multiple beams at the same time.

In other words, even when searching a predetermined search range, if there are two beams, the search time will be halved, and if there are three beams, the search time will be one-third, and so on. This has the advantage that it is possible to shorten the time. Furthermore, when tracking a school of fast-swimming fish after capturing it, tracking with a plurality of beams has the advantage that it is less likely to lose sight of the school of fish than with a single beam.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a transmission pulse when the present invention is applied, FIG. 2 is a block diagram showing an example of the configuration of a transmitting/receiving system when the present invention is applied, and FIG. 3 is (a), (b) Both are diagrams showing an example of a display method. 1-Overall transmission pulse, 2-Pulse transmitted at an depression angle of 01, 3-Pulse transmitted at an depression angle of 02, 4-Transmitter, 5-Transmission/reception switching circuit, 6-Transducer/receiver, 7 - depression angle signal generator, 8.8' - phase shift receiver, 9 distance signal generator, 10 unidirectional scanning signal generator, 11 - time pace generator, 12
．． 12' one-way scanning circuit, 13-distance signal output terminal, 1
4 - Received signal output terminal for depression angle θ, +5 - Received signal output terminal for depression angle θ2, 16.17.18.19, - Display unit. Agent Patent Attorney Yoshihiro Hachiman

Claims (1)

[Claims] In scanning sonar, the transmission time of each period is divided into multiple parts, and pulsed sound waves are sequentially transmitted to different depression angles corresponding to each divided time, and the waves are reflected from the target object and received. An ultrasonic detection method characterized in that the received signal of the sound wave is subjected to azimuth scanning and received signal processing for each of the different angles of depression, and is displayed for each angle of depression.