Techniques are disclosed for systems and methods to provide speed through medium (STM) sensor calibration for mobile structures. An STM sensor calibration system includes a logic device configured to communicate with an STM sensor, an orientation sensor, and a position sensor for a mobile structure. The logic device determines a time series of estimated STM velocities and a time series of speed over ground (SOG) velocities during a dynamic maneuver of the mobile structure. The logic device determines an STM sensor calibration associated with the STM sensor based, at least in part, on the estimated STM velocities and the SOG velocities.

A method for determining the elevation angle and/or azimuth angle of a signal received by an ultrasound sensor includes: providing an ultrasound sensor with a frequency-dependent radiation pattern; transmitting a first ultrasound wave at a first frequency; transmitting a second ultrasound wave at a second frequency different from the first frequency; receiving reflections of the first and second waves, the reflections being caused by an object; and determining the elevation angle of the first and second reflected waves based on amplitudes of the reflections of the first and second waves. Determining the elevation angle (and/or azimuth angle includes calculating a ratio between the amplitudes of received reflections of the first and second waves and mapping a calculated ratio to an elevation angle and/or azimuth angle. The mapping is based on a predetermined ratio curve or ratio dataset which associates a certain amplitude ratio to an elevation angle and/or azimuth angle.

A method for determining the elevation angle and/or azimuth angle of a signal received by an ultrasound sensor includes: providing an ultrasound sensor with a frequency-dependent radiation pattern; transmitting a first ultrasound wave at a first frequency; transmitting a second ultrasound wave at a second frequency different from the first frequency; receiving reflections of the first and second waves, the reflections being caused by an object; and determining the elevation angle of the first and second reflected waves based on amplitudes of the reflections of the first and second waves. Determining the elevation angle (and/or azimuth angle includes calculating a ratio between the amplitudes of received reflections of the first and second waves and mapping a calculated ratio to an elevation angle and/or azimuth angle. The mapping is based on a predetermined ratio curve or ratio dataset which associates a certain amplitude ratio to an elevation angle and/or azimuth angle.

An acoustic dual-frequency phased array system with common beam angles is disclosed. In one aspect, the system includes a planar array of transducer elements and a multiplexing circuit for selecting between a first state and a second state during either transmit operation, receive operation or both transmit and receive operation. The multiplexer is configured to connect transducer elements to a plurality of connections different between the first state and second state. The system is configured to transmit and receive beams at a first frequency when the multiplexer is in the first state and transmit and receive beams at a second frequency when the multiplexer is in the second state. The angle of the beams from vertical in the first and second state are substantially similar.

Disclosed is a LADCP and USBL combined observation device and a use method thereof. The device includes a cable winch system, a mounting frame, a LADCP system, a USBL beacon and a correction system. The LADCP system, the USBL beacon and the correction system can be mounted to the mounting frame by adopting a hardware support platform. The cable winch system can drive the LADCP system to deploy or recover along a vertical section. The LADCP system is used to obtain the current velocity of a single small profile, and the USBL beacon can locate the underwater position information, and the correction system can obtain data information in the seawater where the mounting frame is located, so as to calculate an absolute current velocity according to the velocity obtained by the LADCP system and the current data obtained by the correction system.

Disclosed is a LADCP and USBL combined observation device and a use method thereof. The device includes a cable winch system, a mounting frame, a LADCP system, a USBL beacon and a correction system. The LADCP system, the USBL beacon and the correction system can be mounted to the mounting frame by adopting a hardware support platform. The cable winch system can drive the LADCP system to deploy or recover along a vertical section. The LADCP system is used to obtain the current velocity of a single small profile, and the USBL beacon can locate the underwater position information, and the correction system can obtain data information in the seawater where the mounting frame is located, so as to calculate an absolute current velocity according to the velocity obtained by the LADCP system and the current data obtained by the correction system.

A wave generator for an ultrasonic air data system can be configured to collect data derived from a flow of air in a downstream direction. The wave generator can include an ultrasonic wave source configured to output ultrasonic waves from a first end and a wave shaper connected to the first end of the ultrasonic wave source. The wave shaper can be configured to focus the ultrasonic waves into an area downstream from the ultrasonic wave source bounded by a first plane parallel to the downstream direction and a second plane orthogonal to the first plane.

A railroad car location, speed and heading sensor system including at least one self-powered, tie-mounted sensor node that is applicable universally to different railroad settings without using track circuits, inductive loops, radar systems, and wheel counters and associated disadvantages. Reliable and relatively low cost deterministic and redundant car presence detection is realized when multiple sensor nodes are arranged in a network, which may be a wireless mesh network, that is not affected by environmental conditions.

A survey system including a multibeam echo sounder having a projector array and a hydrophone array in a Mills Cross arrangement uses a multicomponent message to ensonify one or more fans to estimate a Doppler velocity.

A survey system including a multibeam echo sounder having a projector array and a hydrophone array in a Mills Cross arrangement uses a multicomponent message to ensonify one or more fans to estimate a Doppler velocity.