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.

A system for three-dimensional animal tracking in laboratory conditions is proposed. A mobile device that has one infrared and one ultrasonic sensor, equipped with memory and/or radio transmitter, is attached to a moving creature. One compact stationary box is placed in the vicinity; it emits a pre-determined sequence of short infrared pulses, short ultrasonic signals and two planar, radially emitted light beams that move through the area of interest with constant angular speed in two orthogonal directions. The mobile device receives two angular coordinates in the form of two time intervals between an infrared pulse and the next two orthogonal planar beam receptions, and it receives one linear coordinate in the form of the time interval between an infrared pulse and the next ultrasonic signal reception, taking into account the speed of sound in the air. The ultrasonic emitter is driven by a pulse-width modulated signal to make it undetectable by animals.

A location tracking system includes a first plurality of signal receiving and transmitting devices, the members of the first plurality each include an RF transceiver, sound receivers and sound emitters. A second plurality of signal transmitting units, the members of the second plurality each include at least an RF transceiver and a sound emitter. A system control element in communication with the members of the first plurality wherein the control element determines the locations of members of the second plurality based, at least in part, on information received from members of the first plurality.

Disclosed is a method for locating a portable device giving “hands free” access to a vehicle, by a location device intended to be installed in the vehicle, the portable device communicating with the location device by ultra high frequency waves, the invention consisting at each transmission of an ultra high frequency signal by the location device: of simultaneously transmitting by the location device at least one ultrasonic signal, intended for the portable device; of measuring a delay between a first time of reception of the ultra high frequency signal and un second time of reception of the ultrasonic signal by the portable device; of determining a distance between the portable device and the location device on the basis of the delay thus measured. Also disclosed is a location device and a corresponding portable device.

According to one aspect of the invention, the PASS-Tracker is a hand-held device that improves the ability of a rescuer to quickly locate a distressed firefighter by two processes: (1) detecting and recognizing the acoustic alarm sound from a PASS device in Alarm Mode, and (2) providing an indication to rescue personnel of the shortest path to the victim. The invention does not require a pre-installed infrastructure in a particular building; rather the device can be used in an ad hoc fashion at any fire scene. The PASS-Tracker utilizes a plurality of small microphones to detect the acoustic signal from the PASS device. Internal electronics in the PASS-Tracker measure the time-of-arrival (TOA) of the leading edge of the acoustic wave at each microphone and calculate and display the angle-of-arrival (AOA) of the wave.

A method for locating a mobile device is disclosed. Initially, a set of modulated ultrasound signals and a set of radio signals are separately broadcast from a group of transmitters. The ultrasound signals include at least one symbol configured for pulse compression. After the receipt of a demodulated ultrasound signal from a mobile device, wherein the demodulated ultrasound signal is derived from the modulated ultrasound signals, transmitter identifier and timing information are extracted from the demodulated ultrasound signal. Timing information include, for example, the arrival time of the demodulated ultrasound signal in relation to the start time of its transmission. After the locations of the transmitters have been ascertained from the transmitter identifier information, the location of the mobile device can be determined based on the timing information and the locations of the transmitters.

A method for locating a mobile device is disclosed. Initially, a set of modulated ultrasound signals and a set of radio signals are separately broadcast from a group of transmitters. The ultrasound signals include at least one symbol configured for pulse compression. After the receipt of a demodulated ultrasound signal from a mobile device, wherein the demodulated ultrasound signal is derived from the modulated ultrasound signals, transmitter identifier and timing information are extracted from the demodulated ultrasound signal. Timing information include, for example, the arrival time of the demodulated ultrasound signal in relation to the start time of its transmission. After the locations of the transmitters have been ascertained from the transmitter identifier information, the location of the mobile device can be determined based on the timing information and the locations of the transmitters.

In a system and method for operating a system having a rail, a stationary unit, rail-guided mobile parts, and a slotted hollow waveguide, either a first one of the mobile parts or the stationary unit functions as a transmitter, and a second one of the mobile parts functions as a receiver. The transmitter is configured for the simultaneous transmission of an electromagnetic signal and an acoustic signal, e.g., at a first instant. The receiver, which is set apart from the transmitter, is configured to detect the arrival of the electromagnetic signal at a second instant and to detect the arrival of the acoustic signal at a third instant. The second mobile part has an evaluation unit which is configured to determine the distance between the transmitter and the receiver based on the acquired second and third instants.

In a system and method for operating a system having a rail, a stationary unit, rail-guided mobile parts, and a slotted hollow waveguide, either a first one of the mobile parts or the stationary unit functions as a transmitter, and a second one of the mobile parts functions as a receiver. The transmitter is configured for the simultaneous transmission of an electromagnetic signal and an acoustic signal, e.g., at a first instant. The receiver, which is set apart from the transmitter, is configured to detect the arrival of the electromagnetic signal at a second instant and to detect the arrival of the acoustic signal at a third instant. The second mobile part has an evaluation unit which is configured to determine the distance between the transmitter and the receiver based on the acquired second and third instants.

A communication device including a clock, a memory, and at least one processor is disclosed. The at least one processor is configured to execute instructions stored in the memory that cause the at least one processor to perform operations including receiving at least one message from a second communication device of a plurality of communication devices over a preconfigured time duration, determining a first local time of the clock of the communication device at which the at least one message from the second communication device is received, and determining a sync-time of the second communication device based on the at least one message from the second communication device. The operations include mapping the sync-time of the second communication device based on the first local time and the determined sync-time of the second communication device and adjusting a sync-time of the communication device based on the second local time.