The present disclosure relates to a location determination system that includes acoustic transmitting devices (104), location tags (112), and a wireless mesh network (106), where the wireless mesh network uses battery-powered devices. A location tag receives acoustic signals (e.g., ultrasound signals) from an acoustic transmitting device. Clocks from members of the wireless mesh network are synchronized by observation of clock pairings, each clock pair formed by respective clocks in a transmitting device that transmits a message and a receiving device that receives the message. By analyzing the observed clock pairings, a best fit between the clock pairings may be determined. After selecting a reference clock, an acoustic transmission schedule may be propagated to the respective acoustic transmitting device.

A system and methods for estimating the location of a mobile device are disclosed. In accordance with one embodiment, a mobile device located within a first corridor of a building receives (1) a first wireless electromagnetic signal and a first ultrasound signal from a first beacon located in the first corridor, (2) a second wireless electromagnetic signal and a second ultrasound signal from a second beacon located in the first corridor, and (3) a third wireless electromagnetic signal from a third beacon located in a second corridor of the building. The first wireless electromagnetic signal, the first ultrasound signal, the second wireless electromagnetic signal, and the second ultrasound signal are used to estimate a location of the mobile device.

A transmitter is disclosed. The transmitter includes a clock configured to generate one or more output clock signals. The transmitter further includes at least one frequency divider configured to generate a plurality of divided frequencies based on the one or more output clock signals, and a modulator. The transmitter also includes at least one antenna or transducer configured to transmit modulated data. The transmitter includes a memory configured to store instructions, and at least one processor configured to execute instructions performing operations including mapping data to a decimal code value of a plurality of decimal code values, converting the decimal code value to a shrinking base system, and selecting a set of frequencies among the plurality of divided frequencies based on the code value corresponding to the shrinking base system for the decimal code value. The modulator may be configured to modulate the decimal code value using the set of frequencies.

An underwater celestial navigation beacon configured to provide position information is disclosed. The underwater celestial navigation beacon can include a data store configured to store an astronomical model of the moon. The underwater celestial navigation beacon can include an inertial measurement unit (IMU) operable to capture IMU data that includes three-axis acceleration data and three-axis rate gyroscopic data. The underwater celestial navigation beacon can include a controller. The controller can determine a latitude of the underwater celestial navigation beacon using the three-axis rate gyroscopic data. The controller can determine a longitude of the underwater celestial navigation beacon based on a gravitational pull of the moon, using the three-axis acceleration data and the astronomical model of the moon. The controller can determine the position information for the underwater celestial navigation beacon based on the latitude and longitude.

An underwater celestial navigation beacon configured to provide position information is disclosed. The underwater celestial navigation beacon can include a data store configured to store an astronomical model of the moon. The underwater celestial navigation beacon can include an inertial measurement unit (IMU) operable to capture IMU data that includes three-axis acceleration data and three-axis rate gyroscopic data. The underwater celestial navigation beacon can include a controller. The controller can determine a latitude of the underwater celestial navigation beacon using the three-axis rate gyroscopic data. The controller can determine a longitude of the underwater celestial navigation beacon based on a gravitational pull of the moon, using the three-axis acceleration data and the astronomical model of the moon. The controller can determine the position information for the underwater celestial navigation beacon based on the latitude and longitude.

In many applications such as automobiles on busy highways, if a lot of vehicles on road are equipped with Doppler radars to help improve driving safety, no matter human-driven or auto-driven, if the radars use same frequency band, avoiding interference between them is a hard task. Assigning distinct frequencies is one of the solutions, however not only it wastes expensive spectrum resource, but also the task itself to dynamically assign frequency to vehicles randomly come together becomes a hard one to do. The disclosed invention of Doppler group radar will allow radar devices to work together using shared frequency band without interfering one another, without sacrificing performance, and without much increase in costs.

A location system comprising: a location network comprising a plurality of reference nodes and at least one controller. Each reference node is operable to transmit a respective beaconing signal from which a respective measurement can be taken by a mobile device for use in determining a location of the mobile device. The at least one controller is configured to control whether and/or how often one or more signals of the location system are transmitted to be used in determining the location of the mobile device, the control being based on feedback from at least one determination of the location of the mobile device relative to the reference nodes.

The invention relates to hydroacoustics and more specifically to hydroacoustic devices comprising, disposed in a single housing, a converter of liquid-medium oscillations and electrical signals, capable of receiving and/or transmitting hydroacoustic signals, the converter being disposed on a board which is connected to a switch cable for providing power and transmitting electrical signals, and may be used as a receiver and/or transmitter of hydroacoustic signals in water. According to the invention, the housing of the to hydroacoustic device is formed by the outer surfaces of the converter and board, and by a protective material which coats all of said surfaces, said material allowing for a transmission of hydroacoustic oscillations and being capable of transitioning from a highly-elastic or viscous-flow state to a solid state. The achieved technical result consists in simplifying the design of the device.

An ultrasonic locationing system using a dual phase pulse includes an emitter emitting two consecutive frequency bursts, each having a different phase, within one ultrasonic pulse. A receiver microphone receives the ultrasonic pulse, and a processor runs an amplitude-based detection algorithm on the pulse for a band of frequencies of interest and detects a first burst of the pulse within the proper frequency band and having an amplitude exceeding a threshold. Whereupon, the processor determines a relative phase difference between the first burst and a second burst of the pulse and determines whether the relative phase difference is within a predetermined acceptance window, indicating that the pulse is valid for use in locationing the emitter and associated mobile device.

Systems for position determination using an energy chain for guiding supply lines, which energy chain has a movable run which is fixed at an end to a driver and a stationary run wherein the driver moves back and forth along a track. The system has a sensor device for position determination, which is attached to the driver. In one variant, the system comprises guide components, arranged along the track, for lateral guidance of the energy chain of which components at least one has a reference component acting as a position reference. In another variant of the system, at least each nth chain link of the energy chain has at least one reference component attached thereto. In both variants, the sensor device for position determination interacts with individual reference components, which allows better and more reliable determination of the current position.