A space-time calibration system and method implement space-time solutions, in which, in one preferred embodiment, a single node determines its own space-time solutions based on other network nodes with which the single node communicates. In other preferred embodiments, space-time solutions for the node can be generated using other resources in the network. The disclosed system and method enable reliable, precise object positioning particularly for environments where the Global Positioning System (GPS) is blocked or subject to interference such as within the urban core.

A space-time calibration system and method implement space-time solutions, in which, in one preferred embodiment, a single node determines its own space-time solutions based on other network nodes with which the single node communicates. In other preferred embodiments, space-time solutions for the node can be generated using other resources in the network. The disclosed system and method enable reliable, precise object positioning particularly for environments where the Global Positioning System (GPS) is blocked or subject to interference such as within the urban core.

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.

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.

Example implementations relate to determining a location using time difference of arrival (TDOA). For example, a computing device may include a first sensor to receive a signal at a first time, where the signal is generated by a user contact at a particular location on a keyboard associated with the computing device. The computing device also includes a second sensor to receive the signal at a second time and a third sensor to receive the signal at a third time. The computing device may also include a processor. The processor may calculate a set of TDOAs associated with the first time, the second time, and the third time. The processor may determine the particular location of the user contact using a triangulation based on the set of TDOAs and may identify a character on the keyboard, where the character is associated with the particular location.

Example implementations relate to determining a location using time difference of arrival (TDOA). For example, a computing device may include a first sensor to receive a signal at a first time, where the signal is generated by a user contact at a particular location on a keyboard associated with the computing device. The computing device also includes a second sensor to receive the signal at a second time and a third sensor to receive the signal at a third time. The computing device may also include a processor. The processor may calculate a set of TDOAs associated with the first time, the second time, and the third time. The processor may determine the particular location of the user contact using a triangulation based on the set of TDOAs and may identify a character on the keyboard, where the character is associated with the particular location.

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.

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.

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.