ZaiNar, Inc.

A method includes: accessing propagation delay values associated with a signal transmitted from a target device and received at antenna elements of a set of nodes; defining combinations of antenna elements, each combination of antenna elements including an antenna element of each node in the set of nodes. For each combination of antenna elements, the method includes: accessing a group of propagation delay values corresponding to antenna elements in the combination of antenna elements; calculating a candidate position, in a set of candidate positions, occupied by the target device based on the group of propagation delay values. The method includes: isolating a subset of candidate positions, in the set of candidate positions, falling within a selected region in the reference coordinate system; and calculating an estimated position, in the reference coordinate system, occupied by the target device based on a combination of the subset of candidate positions.

A method includes: receiving a ranging signal from the transmitter including a set of multiplexed sub-signals, each multiplexed sub-signal characterized by a frequency in a set of frequencies; calculating a sample-based time-of-arrival estimate based on the series of time-domain samples of the ranging signal; calculating a sample-based uncertainty of the sample-based time-of-arrival; for each sub-signal pair in a subset of multiplexed sub-signals of the set of multiplexed sub-signals, extracting a phase difference of the sub-signal pair; calculating a phase-based time-of-arrival estimate based on the phase difference of each sub-signal pair in the subset of multiplexed sub-signals; calculating a phase-based uncertainty of the phase-based time-of-arrival estimate; and calculating a hybrid time-of-arrival estimate as a weighted combination of the sample-based time-of-arrival estimate, the phase-based time-of-arrival estimate, based on the sample-based uncertainty and the phase-based uncertainty.

A method includes: based on a synchronization signal transmitted from a master node and received at a sniffer node, recording a partial channel-state information characterizing a communication channel between the master node and the sniffer node for a second time period; in response to a localization signal transmitted from a target device, calculating a time bias between the master node and the sniffer node based on a transmit time of the synchronization signal, a third receive time of the synchronization signal at the sniffer node, a channel response characterizing the communication channel for a first time period, and the partial channel-state information; and estimating a position of the target device based on a first receive time of the localization signal at the master node, a second receive time of the localization signal at the sniffer node, and the time bias.

A method of determining a reference clock in a mesh network includes receiving multiple signals, correlating the multiple signals with a local signal generated by the first node to determine a coarse set of time differences, refining the coarse set of time differences using a phase of a carrier signal of the multiple signals to produce a refined set of time differences, and using the refined set of time differences to define a reference clock.

A method includes: based on a synchronization signal transmitted from a master node and received at a sniffer node, recording a partial channel state information characterizing a communication channel between the master node and the sniffer node for a second time period; in response to a localization signal transmitted from a target device, calculating a time bias between the master node and the sniffer node based on a transmit time of the synchronization signal, a third receive time of the synchronization signal at the sniffer node, a channel response characterizing the communication channel for a first time period, and the partial channel state information; and estimating a position of the target device based on a first receive time of the localization signal at the master node, a second receive time of the localization signal at the sniffer node, and the time bias.

A method includes: calculating a first probability distribution representing a first set of probability masses for the device occupying positions of a reference coordinate system based on a first set of time-of-arrival estimates, for a signal transmitted from a device and received at a first node, and a first position occupied by the first node; calculating a second probability distribution representing a second set of probability masses for the device occupying the positions based on a second set of time-of-arrival estimates, for the signal received at a second node, and a second position occupied by the second node; calculating a joint probability distribution for the positions based on a product of the first set of probability masses and the second set of probability masses; and calculating an estimated position occupied by the device, the estimated position characterized by the greatest probability mass in the joint probability distribution.

A method includes: accessing a first time-of-arrival estimate for a reference signal transmitted from a reference device and received at a first node; accessing a second time-of-arrival estimate for the reference signal received at a second node; accessing a first time-of-flight estimate for the reference signal from the reference device to the first node based on a first distance between the reference device and the first node; accessing a second time-of-flight estimate for the reference signal from the reference device to the second node based on a second distance between the reference device and the second node; and calculating a time synchronization offset between the first node and the second node based on the first time-of-arrival estimate, the second time-of-arrival estimate, the first time-of-flight estimate, and the second time-of-flight estimate.

In one embodiment, an asynchronous wireless system for localization of nodes comprises a first wireless node being configured to receive a first communication from a third wireless node having an unknown location, to determine time difference of arrival (TDoA) information of the reception of the first communication between each of the first and a second wireless node, to determine TDoA ranging including a relative or absolute position of the third wireless node using the time difference of arrival information, and to synchronize the first and second wireless nodes based on a second communication with the synchronization being decoupled in time from the first communication. In another embodiment, a computer implemented method comprises receiving, with first and second wireless anchor nodes, packets from a wireless arbitrary device and performing time difference of arrival ranging upon reception of the packets between each of the first and the second wireless anchor nodes.

A method includes: accessing a ranging signal transmitted from a transmitter and received at a set of antenna elements via a channel; recording time domain samples representing the ranging signal; accessing steering matrices characterized by a time delay grid, a phase angle grid, and distances between antenna elements and a reference antenna element; generating a structured data representation of the time domain samples characterized by the steering matrices; calculating a sparse representation of the channel by executing L1-norm regularization based on the structured data representation; and calculating a time of arrival estimate and an angle of arrival estimate for the ranging signal based on the sparse representation of the channel.

A method includes: scheduling transmission of a first synchronization signal by a first node; and scheduling transmission of a second synchronization signal by a second node. The method also includes, after transmission of the first synchronization signal: receiving, from the first node, a first phase reference associated with the first synchronization signal; and receiving, from the second node, a first phase-of-arrival of the first synchronization signal at the second node. The method additionally includes, after transmission of the second synchronization signal: receiving, from the second node, a second phase reference associated with the second synchronization signal; and receiving, from the first node, a second phase-of-arrival of the second synchronization signal at the first node. The method further includes calculating a propagation delay between the first node and the second node based on the first phase reference, the second phase reference, the first phase-of-arrival, and the second phase-of-arrival.