A system and method for improved location tracking of a target device based on location estimates for multiple types of location technologies/sensor types. A received signal strength location estimate of a target device based on wireless transmissions made by the target device received at a plurality of receiver devices at known locations in a location region. A first search area for the target device is derived based on the received signal strength location estimate. An ultrasound based area in which the target device is estimated to be is derived based on reception by the target device of a particular ultrasound beacon in the location region. An intersection of the first search area and the ultrasound based area is computed to produce a second search area. A location estimate of the target device in the second search area is computed based at least on the received signal strength location estimate.

An indoor ultrasonic location tracking system that can utilize standard audio speakers to provide indoor ranging information to modern mobile devices like smartphones and tablets. The method uses a communication scheme based on linearly increasing frequency modulated chirps in the audio bandwidth just above the human hearing frequency range where mobile devices are still sensitive. The method uses gradual frequency and amplitude changes that minimize human perceivable (psychoacoustic) artifacts derived from the non-ideal impulse response of audio speakers. Chirps also benefit from Pulse Compression, which improves ranging resolution and resilience to both Doppler shifts and multi-path propagation that plague indoor environments. The method supports the decoding of multiple unique identifier packets simultaneously. A Time-Difference-of-Arrival pseudo-ranging technique allows for localization without explicit synchronization with the broadcasting infrastructure. An alternate received signal strength indicator based localization technique allows less accurate localization at the benefit of sparser transmission infrastructure.

A programmable buoy system having one or more buoys capable of connecting through the internet to a buoy command server. The buoy command server relays commands to each of the one or more buoys in response to user commands sent from a buoys command interface application on a mobile device. The programmable buoy system includes one or more buoys each having a hull with two or more pontoons where the hull has a top side and bottom side. A stationary rudder extends downward from the bottom side of the hull to be positioned in a body of water when the one or more buoys are in use. A motor is pivotably connected on each one or more buoys, wherein the motor has a propeller positioned away from the bottom side of the hull. The propeller and motor move the select one of the one or more buoys in the body of water.

A location beacon assembly includes a wrist band that may be worn on a wrist. A beacon unit is coupled to the wrist band. The beacon unit is turned on when the beacon unit is exposed to water. The beacon unit selectively emits blue light. Thus, the beacon unit is visible at a maximum depth in water thereby facilitating a swimmer to be located when the swimmer is drowning. The beacon selectively emits an echolocation sound that has a frequency ranging between 10 kHz and 20 kHz. Thus, the beacon unit is audible at a maximum depth in water thereby facilitating the swimmer to be located when the swimmer is drowning.

Techniques for accurate, low-complexity, scalable indoor localization. Low-complexity anchor nodes generate acoustic beacon signals, which are passively detectable by a mobile device, which may be unmodified smartphones operating in an acoustic frequency range. The acoustic beacon signals are modulated via codes in a boundary band of audio and ultrasound frequencies, imperceptible to humans yet detectable via a voice microphone of an unmodified smartphone. An application on the mobile device passively captures the acoustic beacon signals and determines relative distances to the anchor nodes. Localization and distance update techniques, implemented on the mobile device and/or a remote server, determines and updates in real-time the location of the mobile device. The system may be scalable to support any number of mobile devices. Based on the tracked location, the indoor localization system may provide indoor location-based-services (LBS) to the mobile devices, and transmit to the mobile device information relevant to its location.

A position information providing apparatus for providing present position information to a position notifier apparatus is provided. The position information providing apparatus includes an ultrasonic wave output device for outputting ultrasonic wave and a controller for controlling the ultrasonic wave output device. In accordance with contents of the present position information, the controller sequentially selects a modulation frequency from among multiple detectable frequencies which are detectable by the position notifier apparatus and which are lower than an ultrasonic wave frequency. The controller controls the ultrasonic wave output device so that a maximum value or a minimum value of amplitude of the ultrasonic wave varies with to the selected modulation frequency.

A system, device and method that enables units to communicate with each other and point to each other's location without requiring line-of-sight to satellites or any other infrastructure. Further, the system, device and method are able to operate outdoors as well as indoors and overcome multipath interference in a deterministic algorithm, while providing bearings at three dimensions, not only location but actual direction.

In some implementations a method includes receiving a first request for a first ultrasonic audio signature from a first computing device. The method also includes transmitting first data indicative of the first ultrasonic audio signature to the first computing device. The method further includes receiving audio data from a second computing device. The method further includes determining that the audio data is indicative of the first ultrasonic audio signature. The method further includes transmitting, to one or more of the first computing device or the second computing device, a message indicating that the first computing device is in proximity to the second computing device.

An ejectable flight data recorder for robust retention of flight data and aiding in locating an aircraft after an emergency situation comprises: a buoyant housing comprising an internal cavity, a door for access to at least a portion of the internal cavity, and an aerodynamic outer shape having a longitudinal axis; an energy-dissipating nose cone for reducing an impact load on the housing when the flight data recorder impacts a water surface; a nonvolatile memory configured to store flight data; a position sensor for detecting a geographic position of the flight data recorder; a radio transmitter; an antenna electrically coupled to the radio transmitter; a sustainable power system; and a hydrophone for acoustically tracking a sinking trajectory of the aircraft in a body of water.

Provided is an ultrasonic-wave communication system where the influence of ambient noise and the Doppler effect are suppressed and where a user of a portable terminal is prevented from hearing unwanted sound. After performing encryption processing of predetermined information such as store information, a beacon 5 sends out predetermined-information-containing beacon information of one channel as ultrasonic waves into the salesroom 3 by combining a control carrier, a first carrier, and a second carrier in such a way that a first carrier signal and a second carrier signal are output between control carrier signals a number of times according to the predetermined information and that a state where the first carrier signal and/or the second carrier signal is output is maintained.