Commonwealth Scientific and Industrial Research Organisation

Mark Hedley

David Eric Humphrey

Xiaojing Huang

Yingjie Jay Guo

Dan Popescu

Shenghong Li

Thuraiappah Sathyan

Disclosed is method of computing a round trip delay between a pair of nodes, the method comprising transmitting at least one beacon at a known transmit time from each of the nodes; measuring the times-of-arrival of the beacons at other of the nodes; and estimating a round trip delay between the nodes from the measured times-of-arrival and the transmit times; and correcting the round trip delay for either or both of a frequency offset between the nodes and relative motion between the nodes.

Wireless localisation system

Described herein is a method of setting-up a range-based tracking system utilising a tracking coordinate system that uses a plurality of spaced apart stationary nodes for tracking objects within a tracking environment. The method includes the step of transmitting signals between the stationary nodes to obtain range information between at least a subset of pairs of the nodes and determining coordinates for all of the stationary nodes in a node coordinate system using these range information. The method also includes the step of obtaining spatial information related to at least one of the nodes, the spatial information being indicative of one or more features or locations within the tracking environment and determining the location of all stationary nodes in the tracking coordinate system, wherein some or all of the coordinates of the stationary nodes are used for tracking objects in the tracking system.

Method of setting-up a range-based tracking system utilizing a tracking coordinate system

A wireless tracking system comprises mobile devices and stationary devices at known locations. The system receives a first radio measurement indicative of a first propagation path length and receives sensor data indicative of the movement of the first mobile device. The sensor data is of a type different to the radio measurement. The system then determines a historical location of the first mobile device based on the first radio measurement and the sensor data and determines error data indicative of a difference between a historical radio measurement and the historical location and stores the error data associated with the historical location. The system can then receive a second radio measurement indicative of a second propagation path length of radio frequency radiation and determine an estimated location of the second mobile device based on the second radio measurement and the stored error data.

Estimating locations of mobile devices in a wireless tracking system

This disclosure concerns estimating the location of a transmitter using multiple pairs of locator nodes with known locations and measuring time of arrival of a signal received from a transmitter. A processor of a location estimation node first determines time difference of arrival values from time of arrival values measured by each pair of locator nodes. The processor then determines likelihood information for multiple candidate locations of the transmitter and estimates the location of the transmitter from the likelihood information. A processor further determines an initial time of arrival value for the received signal and channel impulse response for a radio channel between the transmitter and receiver. The processor then determines a time correction from the channel impulse response based on a first peak of the channel impulse response and a leading edge of the first value. The processor finally determines an improved time of arrival value of the received signal.

Measuring time of arrival of a signal

Disclosed is an apparatus for estimating the location of a remote node. The apparatus comprises an antenna array comprising a plurality of elements in a fixed spatial arrangement, at least one element being a transmitting element configured to transmit a first wireless signal to the remote node, and at least two elements being receiving elements configured to receive a second wireless signal transmitted by the remote node in response to the first wireless signal. The apparatus further comprises a signal processing unit connected to the antenna array, the signal processing unit being configured to: estimate a plurality of round trip distances using the wireless signals, each round trip distance being from a transmitting element to the remote node and back to a receiving element; and estimate the location of the remote node using the round trip distance estimates.

Disclosed is a method of measuring time of arrival of a signal transmitted from a transmitter () to a receiver (-). The method comprises: modulating a plurality of narrowband signal portions onto different carrier frequencies; transmitting, by the transmitter, each modulated signal portion to the receiver; receiving, by the receiver, the transmitted signal portions; estimating the channel impulse response by combining () the received signal portions; and measuring () the time of arrival using the estimated channel impulse response. Further disclosed is a method of measuring a time of arrival of a signal transmitted from a transmitter to a receiver. The method comprises: estimating a noise level () in an impulse response of a channel between the transmitter and the receiver; finding a first peak () in the channel impulse response that is not noise or a side lobe of a subsequent peak, using the estimated noise level; and measuring the time of arrival () using the first peak.

Measurement of time of arrival

A method and system for dynamically tracking the location of mobile nodes () in a wireless network () is disclosed. The method comprises: for each mobile node, dynamically measuring the range between the mobile node and at least one neighboring node (step); and executing a Bayesian tracking algorithm for each mobile node (step). The algorithm has the measured range as an input, exchanges data with tracking algorithms for neighboring mobile nodes, and utilizes a statistical model of error in measured range and a statistical model of node motion to dynamically determine location.

Growing community of inventors

St. Leonards, Australia

Mark Hedley