A range-finding and/or object-positioning system comprises one or more target devices; one or more reference devices communicating with said one or more target devices via one or more wireless signal sets, each wireless signal set comprising at least a first-speed signal having a first transmission speed and a second-speed signal having a second transmission speed, and the first transmission speed being higher than the second transmission speed; and at least one processing unit performing actions for determining at least one distance between one target device and one reference device based on the time difference between the receiving time of the first-speed signal and the receiving time of the second-speed signal of the wireless signal set communicated between said reference and target devices.

A phase array acoustic device using array of horns and optional faceplates is presented. Said horn phased-array acoustic device can be used as a passive sensor, a sound projector, or both (sonar). It is shown that by correct selection of the fill-factor and apodization faceplate, grating-lobes and side-lobes cab be greatly reduced. An optional use of acoustic valves as phase-shifter in the wave domain to improve Signal to Noise Ratio is presented. An optional aperiodic tiling of the horns' mouth to reduces aliasing is presented.

The present group of inventions relates to methods and systems for positioning underwater objects, and more particularly to methods and systems in which satellite signals are received by receivers disposed on sonar buoys, the coordinates of the sonar buoys are determined by means of computation modules on the sonar buoys, location data and identification data are transmitted in the form of sonar signals emitted by transmitters on the sonar buoys, the signals are received with the aid of a receiver disposed on an underwater object, and the coordinates of the underwater object are determined according to the time delay of receipt of the sonar signals from the sonar buoys, the location of which is known. The present solution can be used in simultaneously determining the geographical position of an unlimited number of mobile underwater objects, remotely operated underwater vehicles, divers, marine animals, etc. in motion. According to the invention, signals from the aforementioned sonar buoys are encoded in the form of periodic signals tethered to GPS/GLONASS clocks, all transmitters of the sonar signals are disposed at the same depth, and during decoding of the signals from the sonar buoys, direct signals from the sonar buoys are isolated from reflected signals. The system implements the aforementioned method. The achieved technical result is more accurate positioning of the underwater objects.

A method for determining the location of a frequency receiver device with respect to at least two frequency originator devices, each of a current location, the method including synchronizing a clock of the frequency receiver device with a clock of one of the at least two frequency originator devices; receiving by the frequency receiver device, a message including an identification code configured for identifying one of the at least two frequency originator devices and obtaining a broadcast time and a current location of the one of the at least two frequency originator devices by looking up a table correlating the at least two frequency originator devices and their respective broadcast times and current locations; calculating a time of flight of the message by calculating the difference between a receive time at which the message is received by the frequency receiver device and the broadcast time.

A range-finding and/or object-positioning system comprises one or more target devices; one or more reference devices communicating with said one or more target devices via one or more wireless signal sets, each wireless signal set comprising at least a first-speed signal having a first transmission speed and a second-speed signal having a second transmission speed, and the first transmission speed being higher than the second transmission speed; and at least one processing unit performing actions for determining at least one distance between one target device and one reference device based on the time difference between the receiving time of the first-speed signal and the receiving time of the second-speed signal of the wireless signal set communicated between said reference and target devices.

A range-finding and/or object-positioning system comprises one or more target devices; one or more reference devices communicating with said one or more target devices via one or more wireless signal sets, each wireless signal set comprising at least a first-speed signal having a first transmission speed and a second-speed signal having a second transmission speed, and the first transmission speed being higher than the second transmission speed; and at least one processing unit performing actions for determining at least one distance between one target device and one reference device based on the time difference between the receiving time of the first-speed signal and the receiving time of the second-speed signal of the wireless signal set communicated between said reference and target devices.

Spatially located ultrasound beacons are provided in known locations within a distributed communication system. The ultrasound beacons are configured to emit ultrasound pulses that can be received by client devices in ultrasound communication range of the beacons. The client devices are configured to analyze the received ultrasound pulses from the beacons to determine their time-difference of arrival and as a result, their location(s) within the distributed communication system. The client devices comprise inertial navigation systems (INS) that calculate client device location as the client device moves, and when received ultrasound signals are below a predefined threshold.

Examples of the disclosure relate to apparatus (101) for positioning mobile devices (105). The apparatus (101) comprises means for: obtaining a time of arrival of at least one audio signal (131) at a mobile device (105), wherein the audio signal (131) is generated with a photoacoustic effect; and using the time of the arrival of the audio signal (131) to estimate a location of the mobile device (105).

Examples of the disclosure relate to apparatus (101) for positioning mobile devices (105). The apparatus (101) comprises means for: obtaining a time of arrival of at least one audio signal (131) at a mobile device (105), wherein the audio signal (131) is generated with a photoacoustic effect; and using the time of the arrival of the audio signal (131) to estimate a location of the mobile device (105).