Enhanced time-difference localization system

Claim 1

An apparatus for locating a mobile radio communications transceiver in an operating environment served by a wireless communications system, comprising: two sensor stations of known location that receive a radio signal from the mobile transceiver, each sensor station having an inter-site synchronization mechanism for common time standard maintenance, and each sensor station further having a corresponding signal characterization processing unit that determines, from the radio signal, time of signal arrival information; a source of collateral information related to a location of the mobile transceiver, wherein the collateral information comprises angle of arrival information determined from the radio signal; a processing unit that determines time difference of signal arrival information based on the time of signal arrival information determined by each said signal characterization processing unit; and a processing unit that determines a probable position of the mobile transceiver based on the time difference of signal arrival information and the collateral information.

Claim 2

An apparatus for locating a mobile radio communications transceiver in an operating environment served by a wireless communications system, comprising: two sensor stations of known location that receive a radio signal from the mobile transceiver, each sensor station having an inter-site synchronization mechanism for common time standard maintenance, and each sensor station further having a corresponding signal characterization processing unit that determines, from the radio signal, time of signal arrival information; a source of collateral information related to a location of the mobile transceiver, wherein the collateral information comprises angle of arrival information determined from the radio signal; a processing unit that determines time difference of signal arrival information based on the time of signal arrival information determined by each said signal characterization processing unit; and a processing unit that determines a probable position of the mobile transceiver based on the time difference of signal arrival information and the collateral information.

Claim 3

A method for locating a mobile radio communications transceiver in a wireless communications system that includes two sensor stations of known location, comprising: receiving, at the two sensor stations, a radio signal from the mobile transceiver; determining time of signal arrival information based on said radio signal received at the two sensor stations; determining time difference of signal arrival information based on said time of signal arrival information; determining collateral information related to a location of the mobile transceiver, wherein the collateral information comprises angle of arrival information that is determined based on said radio signal received at the two sensor stations; and determining a probable position of the mobile transceiver based on said time difference of signal arrival information and the collateral information.

Claim 4

A method for locating a mobile radio communications transceiver in a wireless communications system that includes two sensor stations of known location, comprising: receiving, at the two sensor stations, a radio signal from the mobile transceiver; determining time of signal arrival information based on said radio signal received at the two sensor stations; determining time difference of signal arrival information based on said time of signal arrival information; determining collateral information related to a location of the mobile transceiver, wherein the collateral information comprises angle of arrival information that is determined based on said radio signal received at the two sensor stations; and determining a probable position of the mobile transceiver based on said time difference of signal arrival information and the collateral information.

Claim 5

A system for locating a mobile transceiver relative to plural fixed sensor stations, comprising: (A) a mobile transceiver for transmitting a radio signal; (B) plural fixed sensor stations, each of said sensor stations for receiving said transmitted signal and each comprising: (i) means for determining an angle of arrival of said transmitted signal; and (ii) means for determining a time of arrival of said transmitted signal; and (C) determination means for determining a probable position of the mobile transceiver based on said angle of arrival and said time of arrival.

Claim 6

A system for locating a mobile transceiver relative to plural fixed sensor stations, comprising: (A) a mobile transceiver for transmitting a radio signal; (B) plural fixed sensor stations, each of said sensor stations for receiving said transmitted signal and each comprising: (i) means for determining an angle of arrival of said transmitted signal; and (ii) means for determining a time of arrival of said transmitted signal; and (C) determination means for determining a probable position of the mobile transceiver based on said angle of arrival and said time of arrival.

Claim 7

A system for locating a source of a radio signal, comprising: (A) an inter-site synchronization mechanism for common time standard maintenance; (B) plural sensor stations, each sensor station receiving the radio signal, and each sensor station comprising: (i) an angle of arrival detector for determining an angle of arrival of the radio signal; (ii) a time of arrival detector for determining a time of arrival, at said sensor station, of an identifiable portion of the radio signal, said time of arrival being determined with respect to said inter-site synchronization mechanism; and (iii) reporting means for reporting said angle of arrival and said time of arrival; and (C) a location determining site for receiving said angle of arrival and said time of arrival from each of said plural sensor stations and for determining therefrom a probable position of the source of the radio signal.

Claim 8

A system for locating a source of a radio signal, comprising: (A) an inter-site synchronization mechanism for common time standard maintenance; (B) plural sensor stations, each sensor station receiving the radio signal, and each sensor station comprising: (i) an angle of arrival detector for determining an angle of arrival of the radio signal; (ii) a time of arrival detector for determining a time of arrival, at said sensor station, of an identifiable portion of the radio signal, said time of arrival being determined with respect to said inter-site synchronization mechanism; and (iii) reporting means for reporting said angle of arrival and said time of arrival; and (C) a location determining site for receiving said angle of arrival and said time of arrival from each of said plural sensor stations and for determining therefrom a probable position of the source of the radio signal.

Claim 11

A method for determining a location of a source of a radio signal, comprising the steps of: (A) determining an angle of arrival and a first time of arrival of an identifiable portion of the radio signal at a first sensor station; (B) determining a second time of arrival of said identifiable portion of the radio signal at a second sensor station, said first sensor station and said second sensor station each having an inter-site synchronization mechanism so said first time of arrival and said second time of arrival are coordinated in time; (C) determining a locus of points along the surface of the earth based on a ratio of said first time of arrival and said second time of arrival; and (D) determining, along said locus of points, a point at which an angle of arrival from said first sensor station matches said determined angle of arrival, said point being associated with the source of the radio signal.

Claim 12

A method for determining a location of a source of a radio signal, comprising the steps of: (A) determining an angle of arrival and a first time of arrival of an identifiable portion of the radio signal at a first sensor station; (B) determining a second time of arrival of said identifiable portion of the radio signal at a second sensor station, said first sensor station and said second sensor station each having an inter-site synchronization mechanism so said first time of arrival and said second time of arrival are coordinated in time; (C) determining a locus of points along the surface of the earth based on a ratio of said first time of arrival and said second time of arrival; and (D) determining, along said locus of points, a point at which an angle of arrival from said first sensor station matches said determined angle of arrival, said point being associated with the source of the radio signal.

Claim 14

A system for locating a mobile transceiver, comprising: (a) a mobile transceiver which transmits a signal; (b) plural means for receiving said signal transmitted by said mobile transceiver, said plural means for receiving being geographically diverse from one another to provide locating coverage over a desired geographic territory; and (c) means for decoding said signal received by said plural means for receiving, said means for decoding comprising: (i) means for determining an angle at which said signal from said mobile transceiver arrives at each of said plural means for receiving; (ii) means for determining a time of arrival of said signal from said mobile transceiver at each of said plural means for receiving, whereby said means for decoding determines a probable position of said mobile transceiver based on an angle at which said signal arrived at one of said plural means for receiving and times of arrival of said signal determined at more than one of said plural means for receiving.

Claim 15

A system for locating a mobile transceiver, comprising: (a) a mobile transceiver which transmits a signal; (b) plural means for receiving said signal transmitted by said mobile transceiver, said plural means for receiving being geographically diverse from one another to provide locating coverage over a desired geographic territory; and (c) means for decoding said signal received by said plural means for receiving, said means for decoding comprising: (i) means for determining an angle at which said signal from said mobile transceiver arrives at each of said plural means for receiving; (ii) means for determining a time of arrival of said signal from said mobile transceiver at each of said plural means for receiving, whereby said means for decoding determines a probable position of said mobile transceiver based on an angle at which said signal arrived at one of said plural means for receiving and times of arrival of said signal determined at more than one of said plural means for receiving.