Cambridge Positioning Systems Limited

Craig A Scott

Malcolm David MacNaughtan

Christopher R Drane

A method is disclosed for finding the position of a mobile radio-frequency transceiver in a communication system. A network of at least two unsynchronized base stations is arranged to transmit and receive signals to and from at least one mobile radio frequency transceiver. A reference receiver located at a known distance from the base stations measures the times of arrival of signals transmitted from the base stations. Using the known distances and measured times, a determination is made of the relative time offsets of transmission from each base station. The determined relative time offsets are used to calculate the position of the mobile transceiver in the network area using hyperbolic positioning techniques. A number of other enhancements including the use of Doppler, carrier information, and direction of arrival to improve the performance of mobile telephone-based positioning systems are also described.

Location and tracking system

The invention concerns a method of finding the position of a mobile radio-frequency transceiver in a communications system. A network of at least two unsynchronized base stations arranged to transmit/receive signals to at least one mobile-radio frequency transceiver; a reference receiver located at a known distance from the base stations and including measuring means to measure the times of arrival of signals transmitted from the base stations; determination means to use the known distances and measured times to determine the relative time offsets of transmissions from each base station; and location means to use the determined relative time offsets to calculate the position of a mobile transceiver in the network area using hyperbolic positioning techniques. A number of other enhancements to positioning systems relating to the usage of Doppler, carrier information, direction of arrival to improve the performance of mobile telephone-based positioning systems are also described.

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St. George, Australia

Craig A Scott