Fishfinder

• US 20080080317A1
• Filed: 10/02/2006
• Published: 04/03/2008
• Est. Priority Date: 10/02/2006
• Status: Active Grant

• Current Assignee: Furuno Electric Co, Ltd
• Original Assignee: Furuno Electric Co, Ltd
• Inventors: Shimizu, Toshiyuki, Ogata, Masaki, Inouchi, Mitsuhiro, Mushiake, Masahiko, Okubo, Yoshito
• Granted Patent: US 7,663,974 B2
• Time in Patent Office: Days
• US Class Current: 367/112
• CPC Class Codes: G01S 15/108 using more than one pulse per sonar period
• CPC Class Codes: G01S 15/96 for locating fish
• CPC Class Codes: G01S 7/539 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01S 7/62 Cathode-ray tube displays
• CPC Class Codes: G01S 7/6263 in which different colours are used

Abstract

A fishfinder is provided for identifying with high precision a single fish under the ship and for measuring the length of the fish precisely. An operator of the fishfinder is assisted to grasp the depth and the length of the fish. A fishfinder transmits an ultrasound pulse having a high carrier frequency and an ultrasound pulse having a low carrier frequency by means of a pulse transmission and reception device at predetermined time intervals. A single fish echo is determined and tracked for a plurality of transmission intervals of ultrasound pulses emitted into the water. A target strength of single fish is measured based on the signal strength of a low carrier frequency echo signal from the single fish. The length of the fish is measured based on the target strength. A fish mark is displayed on the screen of an indicator, with the size of the fish mark depending on the fish length.

Claims

1. A detector comprising:

a transmission and reception device for transmitting into the water ultrasound pulses and receiving echo signals;

a single body echo detector for distinguishing a single body echo based on echo signals received; and

a single body echo tracker for tracking a single body distinguished by the single body echo detector for consecutive plurality of transmissions.

2. The detector as claimed in claim 1 wherein the transmission and reception device transmits into the water at least a first ultrasound pulse and receives echo signals in a narrow beam form and transmits a second ultrasound pulse and receives echo signals in a broad beam form.

3. The detector as claimed in claim 2 wherein the single body echo detector determines an echo as a single body echo if the ratio of received signal strength of an echo received with the narrow beam pattern to an echo received with the broad beam pattern is within a predetermined range and if a signal received with the narrow beam pattern rises and falls in accordance with a predetermined condition.

4. The detector as claimed in claim 1 wherein the single body echo tracker tracks a single body distinguished by the single body echo detector in mutually perpendicular two directions for consecutive plurality of transmissions with the one direction representing elapsed time and the other direction representing water depth.

5. The detector as claimed in claim 1 further comprising a body length detector for measuring the length of the body.

6. A detector comprising:

a transmission and reception device for transmitting into the water at least a first ultrasound pulse and receiving echo signals in a narrow beam form and for transmitting a second ultrasound pulse and receiving echo signals in a broad beam form;

a single body echo detector for distinguishing a single body echo based on echo signals received;

a single body echo tracker for tracking a single body distinguished by the single body echo detector for consecutive plurality of transmissions; and

a body length detector for measuring the length of the body based on at least an echo signal received by the transmission and reception device in a broad beam form.

7. A fishfinder comprising:

a transmission and reception device for transmitting into the water at least a first ultrasound pulse in a narrow beam form and a second ultrasound pulse in a broad beam form and receiving echo signals respectively;

a single fish echo detector for distinguishing a single fish echo based on echo signals received;

a single fish echo tracker for tracking a single fish distinguished by the single fish echo detector for consecutive plurality of transmissions; and

a fish length detector for measuring the length of the fish based on at least an echo signal received by the transmission and reception device in a broad beam form.

8. The fishfinder as claimed in claim 7 further comprising an indicator for displaying the length of a single fish or the depth of the fish at a single fish echo detected by the single fish echo detector or in the proximity of the fish echo displayed on the screen of an indicator.

9. The fishfinder as claimed in claim 7, wherein the single fish mark is displayed with a size changing in accordance with the length of the fish on the screen of the indicator.

10. The fishfinder as claimed in claim 7 further comprising an indicator for displaying a display bar moved in synchronism with transmissions of ultrasound pulses into the water, with the display bar indicated single fish information.

11. The fishfinder as claimed in claim 7 further comprising an alarm for providing an alarm if a single fish information meets a predetermined condition.

12. A fish detecting method comprising:

first step for determining the ratio of received signal strength of an echo received with the narrow beam pattern to an echo received with the broad beam pattern is within a predetermined range;

second step for outputting a signal received with the narrow beam pattern rising and falling in accordance with a predetermined condition; and

third step for determining an echo as a single fish echo based on the determination in the first step and the output in the second step.

13. A detector comprising:

a transmission and reception device for transmitting into the water at least a first ultrasound pulse in a narrow beam form and a second ultrasound pulse in a broad beam form and receiving echo signals respectively;

a single body echo detector for distinguishing a single body echo based on echo signals received; and

a single body echo tracker for tracking a single body distinguished by the single body echo detector for consecutive plurality of transmissions to produce a single body echo.