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 method, system and computer program product for controlling a device (e.g., smartphone) by tracking a movement of a target (e.g., finger). A channel impulse response which characterizes signal traversal paths with different delays is estimated. Channel tap(s) corresponding to the target are then selected. The phase change of the selected channel taps is tracked based on the estimated channel impulse response to estimate a distance change of the target from the device. An estimate of an absolute distance between the device and the target is estimated based on the estimated channel impulse response. A more accurate absolute distance between the device and the target is calculated by combining the estimated absolute distance and the estimated distance change. The position of the target is then tracked based on a distance to different landmarks (e.g., microphones) on the device using the more accurate absolute distance and the estimated distance change.

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.

Methods, apparatus, systems and articles of manufacture to detect changes in a physical environment are disclosed. An example apparatus includes a descriptor generator to generate a first descriptor, the descriptor generator including: a chirp producer to emit a chirp into the environment, a chirp recorder to record a response to the chirp from the environment, and a chirp response encoder to generate an encoding of the response to the chirp; a descriptor similarity generator to generate a similarity value, the similarity value to compare the first descriptor to a second descriptor; and a physical change indicator to, in response to the similarity value exceeding a similarity threshold, indicate that a physical change has occurred in the environment.

Techniques are disclosed for systems and methods to provide accurate and reliable compact sonar systems for mobile structures. A sonar system includes multiple sensor channels, each comprising a sonar transmitter and a sonar receiver, and a logic device configured to provide control signals and receive sensor signals from the sensor channels. The logic device is configured to provide transmission signals to sonar transducer assemblies, where signal patterns of the transmission signals are differentiated based at least in part on frequency content. Acoustic returns are processed using the signal patterns to reduce inter-channel pickup between the sensor channels. Resulting sonar data and/or imagery may be displayed to a user and/or used to adjust a steering actuator, a propulsion system thrust, and/or other operational systems of the mobile structure.

Techniques are disclosed for systems and methods to provide accurate and reliable compact sonar systems for mobile structures. A sonar system includes multiple sensor channels, each comprising a sonar transmitter and a sonar receiver, and a logic device configured to provide control signals and receive sensor signals from the sensor channels. The logic device is configured to provide transmission signals to sonar transducer assemblies, where signal patterns of the transmission signals are differentiated based at least in part on frequency content. Acoustic returns are processed using the signal patterns to reduce inter-channel pickup between the sensor channels. Resulting sonar data and/or imagery may be displayed to a user and/or used to adjust a steering actuator, a propulsion system thrust, and/or other operational systems of the mobile structure.

Systems and methods for identifying and locating target objects based on echo signature characteristics are disclosed. According to an aspect, a system includes a transmitter configured to transmit one or more mechanical waves to a target object for echo of the one or more mechanical waves by the target at a predetermined signature characteristic. The system also includes a detector configured to detect the echo. Further, the system includes a computing device configured to identify the predetermined signature characteristic of the detected echo for locating the target object.

Systems and methods for identifying and locating target objects based on echo signature characteristics are disclosed. According to an aspect, a system includes a transmitter configured to transmit one or more mechanical waves to a target object for echo of the one or more mechanical waves by the target at a predetermined signature characteristic. The system also includes a detector configured to detect the echo. Further, the system includes a computing device configured to identify the predetermined signature characteristic of the detected echo for locating the target object.

Provided are methods for detecting objects within a vehicle. The methods can include emitting at least one auditory signal within the vehicle during at least one first time interval; measuring a second auditory signal emitted by an object within the vehicle during the second time interval subsequent to the at least one first time interval, where the emission of the second auditory signal is caused by the emission of the least one first auditory signal; determining a location of the object within the vehicle based on the measurement of the second auditory signal; and generating an alert to a user indicating the location of that object. Systems and computer program products are also provided.