JPH0249182A - Fish detector - Google Patents

Abstract

PURPOSE:To execute an exact fish detection in accordance with detection depth by one set of device by constituting the title detector so that plural detecting systems can be selected in accordance with depth to be surveyed. CONSTITUTION:A detection mode selector 2 selects a detection mode in accordance with the depth to be surveyed. For instance, in the case of the shallow sea, a scan mode is selected. In the case of the scan mode, an ultrasonic beam of a wide directional angle is radiated by transmission of once from a vibrator array 9, and an echo of its ultrasonic beam is brought to high speed scan and received. On the other hand, in the case of the deep sea, a waiting system mode is selected. In the case of the waiting system mode, an ultrasonic beam of a narrow directional angle is transmitted in one direction from said array 9, and its echo is received. Also, in case of the medium sea, a sequential transmitting system mode is selected. In this mode, a beam of a narrow directional angle is scanned in three directions and transmitted from said array 9, and also, each echo of those ultrasonic beams is brought to high speed scan and received.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electronic tilt type fish finder that searches for schools of fish by scanning an ultrasonic beam.

[Prior Art] In a transducer array in which a plurality of transducers that mutually convert ultrasound/electrical signals are arranged in a row, the emitted ultrasonic beam is controlled by controlling the phase and level of driving each transducer. Electronic tilt type fish finders that control the width and direction of the fish are already in widespread use.

First, a method of detecting fish schools using a conventional fish finder will be described.

■ Standby method As shown in Figure 6 (A), the method is to send and receive a beam with a narrow directivity angle in one direction from the hull W. To detect schools of fish in three directions, the beam It is necessary to change the radiation direction and perform transmission and reception three times.

■ Scanning method In order to detect schools of fish over a wide area, as shown in Figure 6 (B), a beam with a wide directivity angle is emitted in one transmission, and the echoes of the transmitted beam are scanned at high speed and received. do.

■ Sequential transmission method This is a method that combines the above two methods, as shown in Figure 6 (C).
It scans and transmits beams with narrow directivity angles in three directions, and simultaneously scans and receives six echoes of those beams at high speed.

Conventionally, a CRT display or a pen recorder has been used as a display means for displaying detection results.

[Problems to be Solved by the Invention] However, in the above fish detection method, the standby method (2) uses a narrow directivity angle for the transmitted beam, which increases the directivity gain and makes it possible to search in the deep sea. Also, it has the advantage that there are few virtual images of the seabed or schools of fish, but if you want to search over a wide area, it is necessary to send and receive data in three directions, which takes time and can lead to missed searches.

The scan method (2) can search a wide range, but the directivity gain of the transmitted waves is low, making it impossible to search deep sea and easily producing virtual images.

■The sequential wave transmission method can search a wide area at high speed without missing any search, but because the width of the transmission pulse is limited by the capacity of the transmitter, it is suitable for moderately deep seas and tends to generate false images.

On the other hand, as for display means, the Cr(T display) is effective for displaying instantaneous images, but it has the disadvantage that display results cannot be seen without such a display system in order to record and reproduce images. Although recorders are effective for long-term time-series recording, they are not suitable for recording instantaneous images.

As described above, each conventional fish finder has its advantages and disadvantages, and it is necessary to have a plurality of fish finders depending on the depth at which fish are detected and the detection method used.

This invention was made to eliminate the above-mentioned problems, and aims to provide a fish finder that can accurately detect schools of fish according to the search range and detection method using a single device. .

[Means for Solving the Problems] The fish finder of the present invention has a standby system that transmits and receives an ultrasonic beam with a narrow directional angle in one direction, and an ultrasonic beam with a wide directional angle that transmits waves twice. There is a scanning method in which the ultrasound beam is emitted and the echoes of the ultrasound beam are scanned and received at high speed, and a beam with a narrow directivity angle is scanned and transmitted in three directions, and each echo of those ultrasound beams is scanned at high speed. The present invention is characterized in that it enables three methods of fish school detection, including a sequential wave transmission method in which waves are received by the user, and is equipped with a CRT display and a recorder as display means.

[Function] According to the fish finder having the above configuration, the optimum fish finding method is selected according to the depth to be searched, and the display means includes:
A CRT display or recorder appropriate for the selected fish detection method is used.

[Embodiment] FIG. 1 is a control block diagram showing an embodiment of the fish finder of the present invention.

1 is a CPU (central processing unit) that centrally controls this fish finder, and is equipped with a control program as described later. 2 is a detection mode selector for selecting the three fish detection modes described above. 3 is a write/read register in which writing and reading of addresses can be performed independently and simultaneously; data in a predetermined direction can be retrieved by giving (writing) azimuth data from the CPU to the address corresponding to the read address. can. 4 is a transmission read counter that provides a read address for the write/read register 3;

5 is the transmission frequency F. 6 is a phase accuracy counter that determines the number of minutes (m) in one wavelength of 360 degrees. 7 is a phase generation circuit consisting of 110M, and by giving a desired azimuth address, a multiphase frequency signal for controlling the phase of the transducer array is read out. When using the transmitting method, the phase is controlled linearly, and when using the scanning method, the phase is controlled in an arc shape. Reference numeral 8 denotes a power amplifier for amplifying and transmitting the multiphase frequency signal read out from the phase generation circuit 6.

9 is a transducer array consisting of a plurality of N transducers;
0 is a trap circuit that switches between transmission and reception; when switching to transmission, the drive signal from the power amplifier 8 is supplied to the transducer array 9°, and when switching to the receiving side, the drive signal is received by the transducer array 9. A signal is provided to a receiving circuit described below.

11 is a preamplifier that amplifies the received signal of the transducer array 9. I2 is a primary carrier frequency generation circuit that generates a carrier signal of frequency fC1 for converting into a frequency that takes spurious removal and broadbandization into consideration in order to realize high-speed scanning during reception; A primary carrier frequency generation circuit 12 is applied to the signal from the amplifier 11.
This is a mixer that mixes multiple carrier signals. 14 is a narrow band filter provided for improving the SZN ratio and removing interference. 23 to 27 in the reception system correspond to the write/read register 3 to phase generation circuit 7 in the transmission system described above, respectively, and from the phase generation circuit 27,
A multiphase frequency signal for tilting to a desired reception direction during reception is output.

15 is a mixer that mixes the multiphase frequency signal with the received signal that has passed through the narrowband filter 14; I6 is an adder that combines the received signals from each of the seven oscillators; By adding them, the transducer array 9 comes to have directivity in the set direction. Reference numeral 17 denotes a wideband filter, which provides the necessary band to obtain range resolution and azimuth echo by high-speed scanning during reception when using the scanning and sequential transmission method. By setting the carrier signal and filters 14 and 17 in this way, it is possible to improve the S/N ratio, which is the most important aspect of the standby system, and to obtain the bandwidth necessary for the scanning and sequential transmission systems. FIG. 5 shows the frequency and spurious characteristics of each signal in the receiving system.

18 is a main amplifier, 19 is an image memory that stores the received signal amplified by the main amplifier 18 as image information, 20 is a pen recording type recorder, and 21 is:
A CRT display is used, and the recorder 20 is used for long-term time series recording, and the display 2I is used for instantaneous video.

Next, the operation of the above device will be explained.

First, the case where the standby mode is selected by the detection mode selector 2 will be described with reference to FIG.

When a clock pulse KP is input manually after the clock pulse reset signal KPR is input, a predetermined read address is output from the counter 4, and a predetermined azimuth address is output from the write/read register 3 based on this read address. When this azimuth address is manually entered into the phase generation circuit 7, a predetermined multiphase frequency signal is read out in order to cause the beam from the transducer array 9 to radiate in the aforementioned azimuth. Also, at this time, a predetermined mode switching signal is sent from the CPU to the phase generation circuit 7, so that the transducer array 9 is linearly phase-controlled by the multiphase frequency signal. By this control, a beam is transmitted from the transducer array 9 in a desired direction with a narrow directivity angle.

Echoes of the transmitted beam are received by the transducer array 9, and the received signal is amplified by the preamplifier 11 via the trap circuit IO. The amplified signal is mixed with the carrier signal from the primary carrier frequency generation circuit 12 in the mixer 13, passes through the narrowband filter 14, and then is input to the mixer 15.

On the other hand, similarly to the operation in the vibration transmission system described above, the multiphase frequency signal output from the phase generation circuit 27 is transmitted to the mixer 15.
By manually inputting the signal and mixing it with the received signal, the transducer array 9 comes to have a directional characteristic, and becomes highly sensitive to the direction of the Eckoff. Next, in the adder 16,
The received signals from each of the N transducers are combined into one, passed through a wideband filter 17, and then amplified by a main amplifier 18.
The image is then stored in the image memory I9. The data stored in the image memory 19 is stored in the recorder 20 or the display 2! It will be displayed on.

Next, the case where the scanning method is selected by the detection mode setter 2 will be explained with reference to FIG.

In this case, by sending a predetermined mode switching signal from the CPU to the phase generation circuit 7, the transducer array 9 is phase-controlled in an arc shape, and the transducer array 9 emits a beam with a wider directivity angle. be done.

At the time of reception, three receiving clock pulses θck are output at predetermined intervals, so that the receiving direction is set in three directions with a narrow directivity angle so that echoes for the transmitted beam with a wide directivity angle can be received. tilted to. The echo image obtained over a wide range in this way is displayed on a display 21 suitable for displaying instantaneous images.

When the sequential transmission method is selected, as shown in FIG. 4, three clock pulses KP for vibration transmission are output at predetermined intervals, so that the transducer array 9 transmits waves in three directions with a narrow directivity angle. A beam is emitted towards the target. On the other hand, in the receiving system, three receiving clock pulses θck are output in response to the clock pulse KP, so that echoes of the transmitted beams in each direction are received. The echo image obtained in this case is displayed on the display 21.

In this way, depending on the settings on the detection mode setter 2, the standby method, scanning method, or sequential wave transmission method can be selected, and each is applicable to deep sea exploration, shallow sea wide range exploration, or medium deep sea exploration. Ru. Further, when the scanning method or the sequential transmission method is selected, the information is displayed on a display 21 suitable for displaying instantaneous images as a display means.

[Effects of the Invention] As explained above, the present invention enables fish detection using the standby method, scan method, and sequential wave transmission method using a fish finder. By using the scanning method, you can search for fish schools over a wide range without having to search, and in the deep sea, use the standby method and transmit with a beam with good directionality to increase the directional gain. In addition, each detection method can be used in a complementary manner, such as using a sequential wave transmission method for moderately deep seas. Furthermore, if high-speed display is required, such as when using a scanning method or a sequential transmission method, it is possible to display on a CRT display. Furthermore, it is also possible to independently display or record the downward direction on a CRT display and the left or right tilt direction on a recorder.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the fish finder of the present invention, and Figs. 2 to 4 show the standby method, scanning method, and sequential wave transmission method implemented with the device shown in Fig. 1. Figure 5 is a time chart showing each operation, and Figure 6 (A
), FIG. 6(B), and FIG. 6(C) are diagrams showing transmitting and receiving beams in the standby mode, scan mode, and sequential wave transmitting mode. 1...CPU, 2...Detection mode selector, 3,23.
・Write/read register, 4.24...counter,
5... Transmission power source frequency generator, 6, 26... Counter, 7.27... Phase generation circuit, 2... Transmission power amplifier, 9... Vibrator array, 10... Trap circuit,
DESCRIPTION OF SYMBOLS 11... Loading amplifier, ■2... Primary carrier frequency generation circuit, 13... Mixer, 14... Narrowband filter, 15... Mixer, 16... Adder, 17
...Broadband filter, 18...Main amplifier, 19...
- Image memory, 20...Recorder, 21...Display device. Figure 1 Patent Applicant Furuno Electric Co., Ltd. Agent Patent Attorney Seihaku Ao and 1 other person Kumi;

Claims (1)

[Claims] (1) A standby method that sends and receives an ultrasonic beam with a narrow directivity angle in one direction, and a method that emits an ultrasonic beam with a wide directivity angle in one transmission and scans the echoes of that ultrasonic beam at high speed. There are three methods of fish detection: a scanning method that receives the waves, and a sequential transmission method that scans and transmits narrow beams in three directions and scans and receives each echo of those ultrasonic beams at high speed. 1. A fish finder characterized by being equipped with a CRT display and a recorder as display means.