Locating a mobile unit using signals from both mobile beacons and stationary beacons

Claim 3

The method of claim 1 , wherein said inferring of said parameters and said inferring of said location are effected by the mobile unit.

Claim 4

The method of claim 1 , wherein said stationary beacons are base stations of a communications system.

Claim 5

The method of claim 1 , wherein said mobile beacons are satellites.

Claim 6

The method of claim 1 , wherein said parameters include pseudoranges.

Claim 7

The method of claim 5 , further comprising the step of: (g) for each of said at least one mobile beacon, inferring, from said respective mobile beacon ranging signal, a rate of change of said pseudorange to said each mobile beacon; and wherein said parameters that are related to said ranges to said mobile beacons include said rates of change.

Claim 10

The method of claim 7 , wherein at least some of said beacons are stationary beacons.

Claim 11

The method of claim 8 , wherein said stationary beacons are base stations of a communications system.

Claim 12

The method of claim 7 , wherein at least some of said beacons are mobile beacons moving on known respective trajectories.

Claim 13

The method of claim 10 , wherein said mobile beacons are satellites.

Claim 14

The method of claim 7 , wherein said at least one parameter includes a pseudorange.

Claim 15

The method of claim 12 , wherein said at least one parameter includes a rate of change of said pseudorange.

Claim 16

The method of claim 13 , wherein said updating is effected using a dynamic estimator.

Claim 17

The method of claim 14 , wherein said dynamic estimator includes a linear optimal estimator.

Claim 18

The method of claim 15 , wherein said linear optimal estimator is a Kalman filter.

Claim 19

The method of claim 14 , wherein said dynamic estimator includes a model of motion of the mobile unit.

Claim 20

The method of claim 7 , wherein said initial estimate of said location is a location of a predefined reference point.

Claim 21

The method of claim 7 , wherein said obtaining of said initial estimate of said location is effected by triangulation.

Claim 22

The method of claim 7 , further comprising the step of: (f) obtaining an initial estimate of a velocity of the mobile unit; said initial state estimate including said initial estimate of said velocity.

Claim 23

A locator system for locating a mobile unit, comprising: (a) a plurality of asynchronous stationary beacons, each said stationary beacon being operative to transmit a respective stationary beacon ranging signal; (b) a plurality of mobile beacons, each said mobile beacon operative to transmit a respective mobile beacon ranging signal while moving on a known respective trajectory, all said mobile beacons being mutually synchronized; and (c) in the mobile unit: (i) a mobile unit clock for producing a mobile unit timing signal; (ii) a first mobile unit receiver for receiving and digitizing said stationary beacon signals; (iii) a second mobile unit receiver for receiving and digitizing said mobile beacon signals, thereby producing corresponding digitized mobile beacon signal; (iv) a memory for storing said digitized mobile beacon signal; (v) a mobile unit processor for transforming each of said stationary beacon signals into a corresponding stationary beacon pseudorange, and for transforming each of said digitized mobile beacon signals into a corresponding mobile beacon pseudorange subsequent to said storing of said each digitized mobile beacon signal in said memory; and (d) at least one reference unit including: (i) a first reference receiver for receiving said mobile beacon signals and inferring therefrom a common start time of said mobile beacon signals, (ii) a second reference unit receiver for receiving at least one of said stationary beacon signals from at least one respective said stationary beacon, (iii) a reference unit clock for producing a reference unit timing signal, (iv) a reference unit processor for inferring, for each said at least one respective stationary beacon, a timing offset between a start time of said at least one respective stationary beacon signal and said common start time of said mobile beacon signals; and (iii) a transmitter for transmitting said at least one timing offset; said first mobile unit receiver being operative to receive said at least one timing offset from each said at least one reference unit transmitter; said pseudoranges being with reference to both said mobile unit timing signal and said at least one timing offset.

Claim 24

A locator system for locating a mobile unit, comprising: (a) a plurality of asynchronous stationary beacons, each said stationary beacon being operative to transmit a respective stationary beacon ranging signal; (b) a plurality of mobile beacons, each said mobile beacon operative to transmit a respective mobile beacon ranging signal while moving on a known respective trajectory, all said mobile beacons being mutually synchronized; and (c) in the mobile unit: (i) a mobile unit clock for producing a mobile unit timing signal; (ii) a first mobile unit receiver for receiving and digitizing said stationary beacon signals; (iii) a second mobile unit receiver for receiving and digitizing said mobile beacon signals, thereby producing corresponding digitized mobile beacon signal; (iv) a memory for storing said digitized mobile beacon signal; (v) a mobile unit processor for transforming each of said stationary beacon signals into a corresponding stationary beacon pseudorange, and for transforming each of said digitized mobile beacon signals into a corresponding mobile beacon pseudorange subsequent to said storing of said each digitized mobile beacon signal in said memory; and (d) at least one reference unit including: (i) a first reference receiver for receiving said mobile beacon signals and inferring therefrom a common start time of said mobile beacon signals, (ii) a second reference unit receiver for receiving at least one of said stationary beacon signals from at least one respective said stationary beacon, (iii) a reference unit clock for producing a reference unit timing signal, (iv) a reference unit processor for inferring, for each said at least one respective stationary beacon, a timing offset between a start time of said at least one respective stationary beacon signal and said common start time of said mobile beacon signals; and (iii) a transmitter for transmitting said at least one timing offset; said first mobile unit receiver being operative to receive said at least one timing offset from each said at least one reference unit transmitter; said pseudoranges being with reference to both said mobile unit timing signal and said at least one timing offset.

Claim 25

The locator system of claim 21 , wherein said mobile unit processor is further operative to transform each said digitized mobile beacon ranging signal into a rate of change of said corresponding mobile beacon pseudorange.

Claim 26

The locator system of claim 21 , wherein said mobile unit processor is further operative to infer a location of the mobile unit from said pseudoranges.

Claim 27

A locator system for locating a mobile unit, comprising: (a) a plurality of beacons, each said beacon transmitting a respective ranging signal; and (b) in the mobile unit: (i) a mechanism for obtaining an initial estimate of a location of the mobile unit, (ii) a receiver for receiving said ranging signals, (iii) a processor for inferring, from one of said ranging signal, at least one parameter related to a range to said beacon that transmitted said one ranging signal, and (iv) an updating mechanism for updating said initial location estimate, based only on an initial state estimate that includes said initial location estimate and on said at least one parameter.

Claim 28

A locator system for locating a mobile unit, comprising: (a) a plurality of beacons, each said beacon transmitting a respective ranging signal; and (b) in the mobile unit: (i) a mechanism for obtaining an initial estimate of a location of the mobile unit, (ii) a receiver for receiving said ranging signals, (iii) a processor for inferring, from one of said ranging signal, at least one parameter related to a range to said beacon that transmitted said one ranging signal, and (iv) an updating mechanism for updating said initial location estimate, based only on an initial state estimate that includes said initial location estimate and on said at least one parameter.

Claim 29

The locator system of claim 24 , wherein at least some of said beacons are stationary.

Claim 30

The locator system of claim 25 , wherein said stationary beacons are base stations of a communications system.

Claim 31

The locator system of claim 26 , wherein at least some of said beacons are mobile beacons moving on known respective trajectories.

Claim 32

The locator system of claim 27 , wherein said mobile beacons are satellites.

Claim 33

The locator system of claim 24 , wherein said at least one parameter includes a pseudorange.

Claim 34

The locator system of claim 29 , wherein said at least one parameter includes a rate of change of said pseudorange.

Claim 35

The locator system of claim 30 , wherein said updating mechanism includes a dynamic estimator.

Claim 36

The locator system of claim 31 , wherein said dynamic estimator includes a linear optimal estimator.

Claim 37

The locator system of claim 32 , wherein said linear optimal estimator is a Kalman filter.

Claim 38

The locator system of claim 31 , wherein said dynamic estimator includes a model of motion of the mobile unit.

Claim 41

The method of claim 35 , wherein said mobile beacons are satellites.

Claim 42

The method of claim 35 , wherein said stationary beacons are base stations of a communications system.

Claim 43

The method of claim 35 , wherein, for at least one of said ranging signal said at least one parameter, that is inferred from said at least one ranging signal, includes a pseudorange.

Claim 44

The method of claim 35 , wherein, for said ranging signal that is received from one of said mobile beacons, said at least one parameter, that is inferred from said ranging signal, includes a pseudorange and a rate of change of said pseudorange.

Claim 45

The method of claim 35 , wherein said updating is effected using a dynamic estimator.

Claim 46

The method of claim 40 , wherein said dynamic estimator includes a linear optimal estimator.

Claim 47

The method of claim 41 , wherein said linear optimal estimator is a Kalman filter.

Claim 48

The method of claim 41 , wherein said dynamic estimator includes a model of motion of the mobile unit.

Claim 49

The method of claim 35 , wherein said initial estimate of said location is a location of a predefined reference point.

Claim 50

The method of claim 44 , wherein said predefined reference point is a location of one of said stationary beacons.

Claim 51

The method of claim 35 , wherein said obtaining of said initial estimate of said location is effected by triangulation.

Claim 52

A locator system for locating a mobile unit, comprising: (a) a plurality of mobile beacons, each said mobile beacon transmitting a respective ranging signal; (b) a plurality of stationary beacons, each said stationary beacon transmitting a respective ranging signal; and (c) in the mobile unit: (i) a mechanism for obtaining an initial estimate of a location of the mobile unit, (ii) a receiver for receiving said ranging signals, (iii) a processor for inferring, from each of said ranging signals, at least one parameter related to a range to said beacon that transmitted said each ranging signal, and (iv) an updating mechanism for updating said initial location estimate, using only; (A) an initial state estimate that includes said initial location estimate, and (B) said at least one parameter that is related to said range to a beacon of one of said pluralities of beacons, thereby providing a first updated location estimate of said location of the mobile unit, and for updating said first updated estimate, using only: (A) an updated state estimate that includes said first updated location estimate, and (B) said at least one parameter that is related to said range to a beacon of another of said pluralities of beacons.

Claim 53

A locator system for locating a mobile unit, comprising: (a) a plurality of mobile beacons, each said mobile beacon transmitting a respective ranging signal; (b) a plurality of stationary beacons, each said stationary beacon transmitting a respective ranging signal; and (c) in the mobile unit: (i) a mechanism for obtaining an initial estimate of a location of the mobile unit, (ii) a receiver for receiving said ranging signals, (iii) a processor for inferring, from each of said ranging signals, at least one parameter related to a range to said beacon that transmitted said each ranging signal, and (iv) an updating mechanism for updating said initial location estimate, using only; (A) an initial state estimate that includes said initial location estimate, and (B) said at least one parameter that is related to said range to a beacon of one of said pluralities of beacons, thereby providing a first updated location estimate of said location of the mobile unit, and for updating said first updated estimate, using only: (A) an updated state estimate that includes said first updated location estimate, and (B) said at least one parameter that is related to said range to a beacon of another of said pluralities of beacons.

Claim 54

The locator system of claim 47 , wherein said mobile beacons are satellites.

Claim 55

The locator system of claim 47 , wherein said stationary beacons are base stations of a communications system.

Claim 56

The locator system of claim 47 , wherein each said at least one parameter includes a pseudorange.

Claim 57

The locator system of claim 47 , wherein, for each said ranging signal that is received from one of said mobile beacons, said at least one parameter, that is inferred from said each ranging signal, includes a pseudorange and a rate of change of said pseudorange.

Claim 58

The locator system of claim 47 , wherein said updating mechanism includes a dynamic estimator.

Claim 59

The locator system of claim 52 , wherein said dynamic estimator includes a linear optimal estimator.

Claim 60

The locator system of claim 53 , wherein said linear optimal estimator is a Kalman filter.

Claim 61

The locator system of claim 52 , wherein said dynamic estimator includes a model of motion of the mobile unit.