Embodiments of the present invention provide a navigation system which, on the one hand, is arranged on sides of the underwater vehicle/AUV and, on the other hand, includes a surface transmitter as a counterpart. The two units communicate with each other such that the surface transmitter emits its signal directed to the position of the underwater vehicle and/or that the surface transmitter follows the underwater vehicle to improve the position determination capability.

A method is provided for localizing an underwater vehicle using acoustic ranging. The method includes receiving, using an acoustic receiver, a time series signal based on one or more acoustic signals transmitted from an acoustic source having a known location; determining a travel time of the waveform from the known location of the acoustic source to the acoustic receiver; and determining a range of the underwater vehicle with respect to the acoustic source based on the travel time of the waveform and a sound speed field taken along a ray trajectory extending from the known location of the acoustic source and intersecting with the acoustic receiver at an expected arrival time and depth of the acoustic signal at the underwater vehicle.

An underwater positioning system provides position information for a rover, moveable within a reference frame. The system may comprise: at least one beacon having a light source, located at a fixed position within the reference frame; an underwater imaging device, moveable with the rover in the reference frame to observe the light source from different viewpoints and determine direction data representing a direction or change in direction of the light source with respect to the imaging device; an orientation sensor, associated with the imaging device to determine an orientation of the imaging device with respect to the reference frame and generate orientation data; and a scaling element for providing scaling data representative of a distance between the imaging device and the light source. Various different beacons may be provided.

In alternative system implementations, the locations of light source(s) and underwater imaging device are reversed between rover and beacon(s).

Methods and apparatus for air to underwater communications. In one example, an optical transceiver configurable between two operational modes includes a laser assembly configured to transmit a modulated laser beam when in a first mode of the two operational modes and to transmit an unmodulated beam when in a second mode of the two operational modes, an optical receiver configured to receiver reflections of the unmodulated laser beam from a surface of a body of water and to output measurement data based on the reflections of the unmodulated laser beam, and a controller configured to determine surface conditions of the surface of the body of water based on the measurement data, to adjust at least one property of the modulated laser beam based on the surface conditions, and to operably switch the laser assembly between the first and second modes.

A practically implementable robust direction-of-arrival (DoA) estimation approach that is resistant to localization errors due to mobility, multipath reflections, impulsive noise, and multiple-access interference. As part of the disclosed invention the inventors consider infrastructure-less 3D localization of autonomous underwater vehicles (AUVs) with no GPS assistance and no availability of global clock synchronization. The proposed method can be extended to challenging communication environments and applied for the localization of assets/objects in space, underground, intrabody, underwater and other complex, challenging, congested and sometimes contested environments. Each AUV leverages known-location beacon signals to self-localize and can simultaneously report its sensor data and measurement location. The approach uses two known location beacon nodes, where the beacons are single-hydrophone acoustic nodes that are deployed at known locations and transmit time-domain coded signals in a spread-spectrum fashion.

A method is disclosed comprising: scanning for one or more signals sent by one or more beacon devices, wherein each signal of the one or more signals comprises an identifier of the beacon device, which has sent the signal of the one or more signals, wherein one or more identifiers of the one or more beacon devices are determined based on the one or more signals of the one or more beacon devices; obtaining a position information representing the position of the at least one first apparatus; and outputting a report information comprising the determined one or more identifiers of the one or more beacon devices and the position information of the at least one first apparatus to allow usage of the outputted report information to determine the position of at least one of the one or more beacon devices. A corresponding apparatus, computer program and system are also provided.

Disclosed are a position locking method of an underwater equipment, a terminal device, a system and a medium. The method comprises: acquiring an optical image and a sonar image taken by an underwater equipment; obtaining a target image by synthesizing the optical image and the sonar image, the target image including at least a target object; determining position offset information of the target object according to the target image; and generating position control parameters of the underwater equipment according to the position offset information, and sending position control parameters to the underwater equipment to make the underwater equipment to lock a position according to the position control parameters. The present application greatly reduces operation difficulty of the underwater equipment in turbid or undercurrent water areas.

Embodiments of the present invention provide a navigation system which, on the one hand, is arranged on sides of the underwater vehicle/AUV and, on the other hand, includes a surface transmitter as a counterpart. The two units communicate with each other such that the surface transmitter emits its signal directed to the position of the underwater vehicle and/or that the surface transmitter follows the underwater vehicle to improve the position determination capability.

A practically implementable robust direction-of-arrival (DoA) estimation approach that is resistant to localization errors due to mobility, multipath reflections, impulsive noise, and multiple-access interference. As part of the disclosed invention the inventors consider infrastructure-less 3D localization of autonomous underwater vehicles (AUVs) with no GPS assistance and no availability of global clock synchronization. The proposed method can be extended to challenging communication environments and applied for the localization of assets/objects in space, underground, intrabody, underwater and other complex, challenging, congested and sometimes contested environments. Each AUV leverages known-location beacon signals to self-localize and can simultaneously report its sensor data and measurement location. The approach uses two known location beacon nodes, where the beacons are single-hydrophone acoustic nodes that are deployed at known locations and transmit time-domain coded signals in a spread-spectrum fashion.

Methods and apparatus for air to underwater communications. In one example, an optical transceiver configurable between two operational modes includes a laser assembly configured to transmit a modulated laser beam when in a first mode of the two operational modes and to transmit an unmodulated beam when in a second mode of the two operational modes, an optical receiver configured to receiver reflections of the unmodulated laser beam from a surface of a body of water and to output measurement data based on the reflections of the unmodulated laser beam, and a controller configured to determine surface conditions of the surface of the body of water based on the measurement data, to adjust at least one property of the modulated laser beam based on the surface conditions, and to operably switch the laser assembly between the first and second modes.