A method of stereoscopic mapping an underwater location includes determining a relative position and relative distance between two separate sensors on separate underwater platforms. Each of the two separate sensors scans a same underwater feature from its respective determined relative position. A stereoscopic image of the underwater feature is created from the two scanned images.

An underwater ultrasonic device includes at least one first ultrasonic transducer and at least one second ultrasonic transducer. The first ultrasonic transducer is configured to transmit a plurality of ultrasonic signals and the second ultrasonic transducer is configured to receive a plurality of reflected signals of the ultrasonic signals. The first ultrasonic transducer and the second ultrasonic transducer are disposed with respect to each other. One of the first ultrasonic transducer and the second ultrasonic transducer is curvilinear and another one of the first ultrasonic transducer and the second ultrasonic transducer is curvilinear or straight linear.

An underwater ultrasonic device includes at least one first ultrasonic transducer and at least one second ultrasonic transducer. The first ultrasonic transducer is configured to transmit a plurality of ultrasonic signals and the second ultrasonic transducer is configured to receive a plurality of reflected signals of the ultrasonic signals. The first ultrasonic transducer and the second ultrasonic transducer are disposed with respect to each other. One of the first ultrasonic transducer and the second ultrasonic transducer is curvilinear and another one of the first ultrasonic transducer and the second ultrasonic transducer is curvilinear or straight linear.

A system for searching for underground entities in ground of an area, including a search probe configured to generate and deliver an acoustic signal into the ground of the area, wherein the acoustic signal uses a low frequency signal so that wavelengths of the acoustic signal are between 0.01-500 times the depth to the sought underground entity, two or more sensors positioned on the ground at about an equal distance from the search probe at different angles, an analysis device that receives measurements from the two or more sensors in the form of a measured echo signal responsive to the delivered acoustic signal, wherein said analysis device designates pairs of sensors and subtracts their echo signals to identify a difference indicating the existence of an underground entity.

A system for searching for underground entities in ground of an area, including a search probe configured to generate and deliver an acoustic signal into the ground of the area, wherein the acoustic signal uses a low frequency signal so that wavelengths of the acoustic signal are between 0.01-500 times the depth to the sought underground entity, two or more sensors positioned on the ground at about an equal distance from the search probe at different angles, an analysis device that receives measurements from the two or more sensors in the form of a measured echo signal responsive to the delivered acoustic signal, wherein said analysis device designates pairs of sensors and subtracts their echo signals to identify a difference indicating the existence of an underground entity.

An object detection device includes: first and second transmission/reception units spaced apart from each other and configured to transmit an exploration wave and receive the exploration wave reflected by an object; and a processing unit configured to calculate a position of the object based on reception results by the first and second transmission/reception units. The processing unit includes: a distance processing unit configured to calculate first and second points based on the reception results, and calculates a separation distance between the first and second points; a position calculation unit configured to calculate the position based on the first and second points; a reflection intensity processing unit configured to calculate a reflection intensity indicating an intensity of the exploration wave received by the first and second transmission/reception units; and a position correction unit configured to correct the position based on the separation distance and the reflection intensity.

An object detection device includes: first and second transmission/reception units spaced apart from each other and configured to transmit an exploration wave and receive the exploration wave reflected by an object; and a processing unit configured to calculate a position of the object based on reception results by the first and second transmission/reception units. The processing unit includes: a distance processing unit configured to calculate first and second points based on the reception results, and calculates a separation distance between the first and second points; a position calculation unit configured to calculate the position based on the first and second points; a reflection intensity processing unit configured to calculate a reflection intensity indicating an intensity of the exploration wave received by the first and second transmission/reception units; and a position correction unit configured to correct the position based on the separation distance and the reflection intensity.

Methods and systems for estimating a distance between an acoustic sensor and an acoustic reflector in a conduit are disclosed. One such method includes using the acoustic sensor to measure a combined acoustic signal that comprises an originating acoustic signal propagating along the conduit and an echo signal. The echo signal is generated by the originating acoustic signal reflecting off the acoustic reflector after propagating past the acoustic sensor. A frequency domain representation of the combined acoustic signal is determined and the echo signal is identified by identifying in the frequency domain representation periodic oscillations having a peak-to-peak difference between 0.75 Hz and 1500 Hz. The distance between the acoustic sensor and the acoustic reflector is determined from the velocity of the echo signal and a time required for the echo signal to propagate between the acoustic sensor and the acoustic reflector.

Methods and systems for estimating a distance between an acoustic sensor and an acoustic reflector in a conduit are disclosed. One such method includes using the acoustic sensor to measure a combined acoustic signal that comprises an originating acoustic signal propagating along the conduit and an echo signal. The echo signal is generated by the originating acoustic signal reflecting off the acoustic reflector after propagating past the acoustic sensor. A frequency domain representation of the combined acoustic signal is determined and the echo signal is identified by identifying in the frequency domain representation periodic oscillations having a peak-to-peak difference between 0.75 Hz and 1500 Hz. The distance between the acoustic sensor and the acoustic reflector is determined from the velocity of the echo signal and a time required for the echo signal to propagate between the acoustic sensor and the acoustic reflector.

A system for searching for underground entities in ground of an area, including a search probe configured to generate and deliver an acoustic signal into the ground of the area, wherein the acoustic signal uses a low frequency signal so that wavelengths of the acoustic signal are between 0.01-500 times the depth to the sought underground entity, two or more sensors positioned on the ground at about an equal distance from the search probe at different angles, an analysis device that receives measurements from the two or more sensors in the form of a measured echo signal responsive to the delivered acoustic signal, wherein said analysis device designates pairs of sensors and subtracts their echo signals to identify a difference indicating the existence of an underground entity.