A system is provided for imaging an underwater environment. The system includes one or more arrays of transducer elements. Each array is operated at a fixed phase shift and varies in frequency so as to beamform multiple sonar return beams of a first range of angles and a second range of angles. The arrays can be oriented to cover the gap in sonar coverage for other arrays to create a continuous arc of sonar coverage. Accordingly, a 2D live sonar image can be formed. One or more of the multiple sonar return beams facing downwardly can be selected and used to form downward sonar images that anglers are used to, without requiring separate transducer elements. Fish arches formed using multiple sonar return beams can be positioned appropriately within a high resolution downward sonar image to form a desirable combined sonar image.

A system is provided for imaging an underwater environment. The system includes one or more arrays of transducer elements. Each array is operated at a fixed phase shift and varies in frequency so as to beamform multiple sonar return beams of a first range of angles and a second range of angles. The arrays can be oriented to cover the gap in sonar coverage for other arrays to create a continuous arc of sonar coverage. Accordingly, a 2D live sonar image can be formed. Three arrays are mounted in a housing in an X plus Line configuration with one of the arrays extending below the center of the X.

A measuring device is provided, having a housing having a circuit board and processor; a first transducer arranged on a surface of the housing and configured to transmit an ultrasonic pulse towards a target surface; a second transducer adjacent to the first transducer configured to receive a reflection of the ultrasonic pulse off of the target surface; and a thermistor on the surface of the housing adjacent to the first and second transducers and configured to measure air temperature surrounding the device. The processor of the device is configured to measure a time duration between transmitting the ultrasonic pulse by the first transducer and receiving the reflection of the ultrasonic pulse by the second transducer, and to determine a distance between a ground surface upon which the device is resting and the target surface based at least upon the measured time duration and the measured air temperature.

A measuring device is provided, having a housing having a circuit board and processor; a first transducer arranged on a surface of the housing and configured to transmit an ultrasonic pulse towards a target surface; a second transducer adjacent to the first transducer configured to receive a reflection of the ultrasonic pulse off of the target surface; and a thermistor on the surface of the housing adjacent to the first and second transducers and configured to measure air temperature surrounding the device. The processor of the device is configured to measure a time duration between transmitting the ultrasonic pulse by the first transducer and receiving the reflection of the ultrasonic pulse by the second transducer, and to determine a distance between a ground surface upon which the device is resting and the target surface based at least upon the measured time duration and the measured air temperature.

A system is provided for imaging an underwater environment. The system includes one or more arrays of transducer elements. Each array is operated at a fixed phase shift and varies in frequency so as to beamform multiple sonar return beams of a first range of angles and a second range of angles. The arrays can be oriented to cover the gap in sonar coverage for other arrays to create a continuous arc of sonar coverage. Accordingly, a 2D live sonar image can be formed. One or more of the multiple sonar return beams facing downwardly can be selected and used to form downward sonar images that anglers are used to, without requiring separate transducer elements. Fish arches formed using multiple sonar return beams can be positioned appropriately within a high resolution downward sonar image to form a desirable combined sonar image.

A processor of a sonar system extracts a signal in a predetermined time range from a signal received by an acoustic array, calculates a correlation value for a signal waveform extracted, detects a peak value of the correlation value, calculates an integrated value by performing time-integration of a square of the correlation value, obtains a target velocity based on the peak value and the integrated value, and displays the target velocity on a display apparatus.

A flasher type fish finder has: a motor with a rotary shaft having play in an axial direction; a display rotating disk fixed to the rotary shaft; a first installation part; and a second installation part fixed to a member not influenced by the play. In the first installation part, a magnet or a ferromagnetic material is on the rotary shaft or the display rotating disk such that the center of gravity is at the rotary shaft center. In the second installation part, a magnet or a ferromagnetic material is provided occurring an attraction force or a repulsive force in the axial direction, for the magnet or the ferromagnetic material of the first installation part. The magnet is in at least one of the first installation part and the second installation part. The surfaces of a first magnetic pole and a second magnetic pole are orthogonal to the rotary shaft.

A processor of a sonar system extracts a signal in a predetermined time range from a signal received by an acoustic array, calculates a correlation value for a signal waveform extracted, detects a peak value of the correlation value, calculates an integrated value by performing time-integration of a square of the correlation value, obtains a target velocity based on the peak value and the integrated value, and displays the target velocity on a display apparatus.

A flasher type fish finder has: a motor with a rotary shaft having play in an axial direction; a display rotating disk fixed to the rotary shaft; a first installation part; and a second installation part fixed to a member not influenced by the play. In the first installation part, a magnet or a ferromagnetic material is on the rotary shaft or the display rotating disk such that the center of gravity is at the rotary shaft center. In the second installation part, a magnet or a ferromagnetic material is provided occurring an attraction force or a repulsive force in the axial direction, for the magnet or the ferromagnetic material of the first installation part. The magnet is in at least one of the first installation part and the second installation part. The surfaces of a first magnetic pole and a second magnetic pole are orthogonal to the rotary shaft.

A detection apparatus is provided. The detection apparatus includes a hardware processor programmed to at least calculate a first echo intensity of a first reception signal generated from a reception wave reflected on reflection objects, calculate a second echo intensity of a second reception signal generated from a reception wave reflected on the reflection objects, a signal duration of the second reception signal being shorter than that of the first reception signal, generate a first frequency distribution of the first echo intensity, generate a second frequency distribution of the second echo intensity, and extract a density of the reflection objects or an index of density of the reflection objects based on a comparison of the first frequency distribution and the second frequency distribution.