Navigation and positioning system and method using uncoordinated becon signals

Claim 2

In a positioning system that makes use of a multiplicity of transmitters, at known fixed locations, each of which transmits a beacon signal having a phase that is un-synchronized with the phases of the beacon signals of the other transmitters; each of said beacon signals having a frequency that is approximately equal to a predetermined target frequency; the combination comprising: a first receiver, at a known location relative to the locations of said multiplicity of transmitters, which (A) receives said beacon signals, (B) determines the relative phases of said beacon signals, and (C) transmits data representing said relative phases; a second receiver, at an unknown location, which receives said transmitted data from said first receiver and at least three of said beacon signals, said second receiver including phase detection circuitry for detecting the phases of said beacon signals at the location of said second receiver, and computation means for computing the location of said second receiver based on said transmitted data and said detected phases; and initialization means for providing a common timing signal to said first and second receivers in order to establish a common time basis therebetween, said initialization means including means for determining an initial estimate of said unknown location using said common time basis.

Claim 3

The positioning system of claim 1, said initialization means including a reference transmitter for transmitting said common timing signal; said first receiver including first means for receiving said common timing signal; said second receiver including second means for receiving said common timing signal.

Claim 4

The positioning system of claim 2, said first receiver including a first reference clock and means for identifying a first receipt time, registered by said first reference clock, corresponding to receipt of said common timing signal by said first receiver; said second receiver including a second reference clock and means for identifying a second receipt time, registered by said second reference clock, at which said common timing signal is received by said second receiver wherein said first and second reference clocks are un-synchronized.

Claim 5

The positioning system of claim 3, said first receiver including means for communicating said first time to said second receiver; said initialization means including: means for determining a time difference between said first and second receipt times, and means for calculating said estimate of said unknown location at least partially on the basis of said time difference.

Claim 6

In a positioning system that makes use of a multiplicity of transmitters, at known fixed locations, each of which transmits a beacon signal having a phase that is un-synchronized with the phases of the beacon signals of the other transmitters; each of said beacon signals having a frequency that is approximately equal to a predetermined target frequency; the combination comprising: a first receiver, at a known location relative to the locations of said multiplicity of transmitters, which (A) receives said beacon signals, (B) determines the relative phases of said beacon signals, and (C) generates a set of phase data representing said relative phases; a second receiver, at an unknown location, which receives at least three of said beacon signals, said second receiver including phase detection circuitry for detecting the phases of said beacon signals at the location of said second receiver; computation means, coupled to said second receiver for receiving from said second receiver values corresponding to said detected beacon signal phases, coupled to said first receiver for receiving said generated phase data, and including means for computing the location of said second receiver based on said generated phase values and said detected beacon signal phases; and initialization means for providing a common timing signal to said first and second receivers in order to establish a common time basis therebetween, said initialization means including means for determining an initial estimate of said unknown location using said common time basis; said initialization means including a reference transmitter for transmitting said common timing signal; said first receiver including first means for receiving said common timing signal; said second receiver including second means for receiving said common timing signal.

Claim 7

In a positioning system that makes use of a multiplicity of transmitters, at known fixed locations, each of which transmits a beacon signal having a phase that is un-synchronized with the phases of the beacon signals of the other transmitters; each of said beacon signals having a frequency that is approximately equal to a predetermined target frequency; the combination comprising: a first receiver, at a known location relative to the locations of said multiplicity of transmitters, which (A) receives said beacon signals, (B) determines the relative phases of said beacon signals, and (C) generates a set of phase data representing said relative phases; a second receiver, at an unknown location, which receives at least three of said beacon signals, said second receiver including phase detection circuitry for detecting the phases of said beacon signals at the location of said second receiver; computation means, coupled to said second receiver for receiving from said second receiver values corresponding to said detected beacon signal phases, coupled to said first receiver for receiving said generated phase data, and including means for computing the location of said second receiver based on said generated phase values and said detected beacon signal phases; and initialization means for providing a common timing signal to said first and second receivers in order to establish a common time basis therebetween, said initialization means including means for determining an initial estimate of said unknown location using said common time basis; said initialization means including a reference transmitter for transmitting said common timing signal; said first receiver including first means for receiving said common timing signal; said second receiver including second means for receiving said common timing signal.

Claim 8

The positioning system of claim 5, said first receiver including a first reference clock and means for identifying a first receipt time, registered by said first reference clock, corresponding to receipt of said common timing signal by said first receiver; said second receiver including a second reference clock and means for identifying a second receipt time, registered by said second reference clock, at which said common timing signal is received by said second receiver wherein said first and second reference clocks are un-synchronized.

Claim 9

The positioning system of claim 6, said first receiver including means for communicating said first time to said second receiver; said initialization means including: means for determining a time difference between said first and second receipt times, and means for calculating said estimate of said unknown location at least partially on the basis of said time difference.

Claim 10

In a positioning system that makes use of a multiplicity of transmitters, at known fixed locations, each of which transmits a beacon signal having a phase that is un-synchronized with the phases of the beacon signals of the other transmitters; each of said beacon signals having a frequency that is approximately equal to a predetermined target frequency; the combination comprising: a first receiver, at a known location relative to the locations of said multiplicity of transmitters, which (A) receives said beacon signals, (B) determines the frequency and relative phases of said beacon signals, and (C) which transmits values corresponding to said frequencies and relative phases; a second receiver, at an unknown location, which receives said transmitted values from said first receiver and at least four of said beacon signals, said second receiver including phase detection circuitry for detecting the phases of said beacon signals at the location of said second receiver, and computation means for computing the location of said second receiver based on said transmitted values and said detected phases; and initialization means for providing a common timing signal to said first and second receivers in order to establish a common time basis therebetween, said initialization means including means for determining an initial estimate of said unknown location using said common time basis.

Claim 11

In a positioning system that makes use of a multiplicity of transmitters, at known fixed locations, each of which transmits a beacon signal having a phase that is un-synchronized with the phases of the beacon signals of the other transmitters; each of said beacon signals having a frequency that is approximately equal to a predetermined target frequency; the combination comprising: a first receiver, at a known location relative to the locations of said multiplicity of transmitters, which (A) receives said beacon signals, (B) determines the frequency and relative phases of said beacon signals, and (C) which transmits values corresponding to said frequencies and relative phases; a second receiver, at an unknown location, which receives said transmitted values from said first receiver and at least four of said beacon signals, said second receiver including phase detection circuitry for detecting the phases of said beacon signals at the location of said second receiver, and computation means for computing the location of said second receiver based on said transmitted values and said detected phases; and initialization means for providing a common timing signal to said first and second receivers in order to establish a common time basis therebetween, said initialization means including means for determining an initial estimate of said unknown location using said common time basis.

Claim 14

The method of claim 9, further including the steps of: transmitting said common timing signal; at said known location, receiving said common timing signal and identifying a first time of receipt of said common timing signal at said known location in accordance with a time registered by a first reference clock at said known location; and at said unknown location, receiving said common timing signal and identifying a second time of receipt of said common timing signal at said unknown location in accordance with a time registered by a second reference clock at said unknown location wherein said first and second reference clocks are un-synchronized.

Claim 15

The method of claim 10, further including the steps of: determining a time difference between said first and second receipt times, and calculating said estimate of said unknown location at least partially on the basis of said time difference.

Claim 18

A positioning system for use with a multiplicity of transmitters that are positioned at known fixed locations, wherein each transmitter transmits a beacon signal having a phase that is un-synchronized with the phases of the beacon signals of the other transmitters; each of said beacon signals having a frequency which is approximately equal to a predetermined target frequency; said positioning system comprising: a first receiver, at a known location relative to the locations of said multiplicity of transmitters, which (A) receives said beacon signals, (B) determines the phases and frequencies of said beacon signals at times determined with reference to a first time reference signal, and (C) transmits phase and frequency data representing said beacon signal phases and frequencies; said transmitted phase and frequency data including time data representing when, relative to said first time reference signal, said beacon signals attained said beacon signal phases; and a second receiver, at an unknown location, which receives said transmitted phase and frequency data from said first receiver and at least three of said beacon signals, said second receiver including a local clock generator, un-synchronized with said first time reference signal, that generates a second time reference signal, phase detection circuitry for detecting, at times determined with reference to said second time reference signal, the phases and frequencies of said beacon signals at the location of said second receiver, and computation means for computing, based on said transmitted phase and frequency data and said detected phases and frequencies, coordinate values defining Said second receiver's position and a time adjustment value for bringing said second time reference signal into alignment with said first time reference signal, Said time adjustment value further relating said detected phases to said transmitted phase data in accordance with a predefined set of simultaneous equations.

Claim 19

A positioning system for use with a multiplicity of transmitters that are positioned at known fixed locations, wherein each transmitter transmits a beacon signal having a phase that is un-synchronized with the phases of the beacon signals of the other transmitters; each of said beacon signals having a frequency which is approximately equal to a predetermined target frequency; said positioning system comprising: a first receiver, at a known location relative to the locations of said multiplicity of transmitters, which (A) receives said beacon signals, (B) determines the phases and frequencies of said beacon signals at times determined with reference to a first time reference signal, and (C) transmits phase and frequency data representing said beacon signal phases and frequencies; said transmitted phase and frequency data including time data representing when, relative to said first time reference signal, said beacon signals attained said beacon signal phases; and a second receiver, at an unknown location, which receives said transmitted phase and frequency data from said first receiver and at least three of said beacon signals, said second receiver including a local clock generator, un-synchronized with said first time reference signal, that generates a second time reference signal, phase detection circuitry for detecting, at times determined with reference to said second time reference signal, the phases and frequencies of said beacon signals at the location of said second receiver, and computation means for computing, based on said transmitted phase and frequency data and said detected phases and frequencies, coordinate values defining Said second receiver's position and a time adjustment value for bringing said second time reference signal into alignment with said first time reference signal, Said time adjustment value further relating said detected phases to said transmitted phase data in accordance with a predefined set of simultaneous equations.

Claim 20

The positioning system of claim 13, said second receiver including a single, frequency scanning radio signal receiver for sequentially receiving selected beacon signals at a multiplicity of distinct carrier frequencies; said phase-detection circuitry including a single digital phase-locked loop, coupled to said frequency scanning radio signal receiver, which receives said beacon signal and generates a phase error signal; said computation means including phase computation means, coupled to said phase-detection circuitry, for integrating said phase error signal while said second receiver is receiving each said selected beacon signal, and generating a distinct phase and frequency value for each said selected beacon signal; said computation means further including software means for performing a predefined position computation using said generated phase and frequency values and said transmitted phase and frequency data received from said first receiver.

Claim 21

The positioning system of claim 13, said second receiver including memory means storing transmitter position data indicating the positions of said multiplicity of transmitters; said computation means including software means for performing a predefined position computation using said stored transmitter position data to generate a position value for said second receiver which is consistent with said stored transmitter position data.

Claim 22

The positioning system of claim 13, wherein said beacon signal transmitted by each of said transmitters comprises an FM radio station sub-carrier signal having a frequency of approximately 19 KHz.

Claim 23

The positioning system of claim 13, wherein said beacon signal transmitted by each of said transmitters comprises a sub-carrier signal on a radio station carrier signal, said sub-carrier having a frequency between 1 KHz and 100 KHz.

Claim 24

The positioning system of claim 13, said computation means including (A) phase adjustment means for adjusting said detected phases in accordance with said detected frequencies so as to represent said detected phases at a common time relative to said second time reference signal prior to computing said coordinate values and time adjustment value; and (B) memory means for storing transmitter position data indicating positions of said transmitters with respect to a predefined coordinate system; and (C) means for performing a predefined position computation using said stored transmitter position data to generate a position value in said predefined coordinate system for said second receiver.

Claim 25

The positioning system of claim 13, said first receiver including a first clock generator that generates said first time reference signal.

Claim 26

A positioning system for use with a multiplicity of transmitters, at known fixed locations, each of which transmits a beacon signal having a phase that is un-synchronized with the phases of the beacon signals of the other transmitters; each of said beacon signals having a frequency which is approximately equal to a predetermined target frequency; said positioning system comprising: a first receiver, at a known location relative to the locations of said multiplicity of transmitters, which (A) receives said beacon signals, (B) determines the phases and frequencies of said beacon signals at times determined with reference to a first time reference signal, and (C) transmits phase and frequency data representing said beacon signal phases and frequencies; said transmitted phase and frequency data including time data representing when, relative to said first time reference signal, said beacon signals attained said beacon signal phases; a second receiver, at an unknown location, which receives at least three of said beacon signals, said second receiver including: a local clock generator, un-synchronized with said first time reference signal, that generates a second time reference signal; and phase detection circuitry for detecting, at times determined with reference to said second time reference signal, the phases and frequencies of said received beacon signals at the location of said second receiver; and position computation means which receives said transmitted phase and frequency data from said first receiver and said phases and frequencies detected by said second receiver, said position computing means including means for computing, based on said transmitted phase and frequency data and said detected phases and frequencies, coordinate values defining said second receiver's position and a time adjustment value for bringing said second time reference signal into alignment with said first time reference signal, said time adjustment value further relating said detected phases to said transmitted phase data in accordance with a predefined set of simultaneous equations.

Claim 27

A positioning system for use with a multiplicity of transmitters, at known fixed locations, each of which transmits a beacon signal having a phase that is un-synchronized with the phases of the beacon signals of the other transmitters; each of said beacon signals having a frequency which is approximately equal to a predetermined target frequency; said positioning system comprising: a first receiver, at a known location relative to the locations of said multiplicity of transmitters, which (A) receives said beacon signals, (B) determines the phases and frequencies of said beacon signals at times determined with reference to a first time reference signal, and (C) transmits phase and frequency data representing said beacon signal phases and frequencies; said transmitted phase and frequency data including time data representing when, relative to said first time reference signal, said beacon signals attained said beacon signal phases; a second receiver, at an unknown location, which receives at least three of said beacon signals, said second receiver including: a local clock generator, un-synchronized with said first time reference signal, that generates a second time reference signal; and phase detection circuitry for detecting, at times determined with reference to said second time reference signal, the phases and frequencies of said received beacon signals at the location of said second receiver; and position computation means which receives said transmitted phase and frequency data from said first receiver and said phases and frequencies detected by said second receiver, said position computing means including means for computing, based on said transmitted phase and frequency data and said detected phases and frequencies, coordinate values defining said second receiver's position and a time adjustment value for bringing said second time reference signal into alignment with said first time reference signal, said time adjustment value further relating said detected phases to said transmitted phase data in accordance with a predefined set of simultaneous equations.

Claim 28

The positioning system of claim 20, said first receiver including a first clock generator that generates said first time reference signal.

Claim 29

The positioning system of claim 20, said second receiver receiving at least four of said beacon signals and detecting the phases and frequencies of said at least four beacon signals at the location of said second receiver at times determined with reference to said second time reference signal; and said coordinate values computed by computation means comprising a three-dimensional set of coordinate values defining said second receiver's position with respect to a predefined three-dimensional coordinate system.