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Device for and method of geolocation

  • US 7,893,875 B1
  • Filed: 03/11/2009
  • Issued: 02/22/2011
  • Est. Priority Date: 10/31/2008
  • Status: Active Grant
First Claim
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1. A device for geolocation, comprising:

  • a) a first transmitter to be geolocated;

    b) a first receiver for receiving a signal transmitted by the transmitter, where the first receiver is in motion;

    c) a second receiver for receiving the signal transmitted by the transmitter, where the second receiver is in motion;

    d) a first digitizer on said first receiver for digitizing the signal received by the first receiver;

    e) a second digitizer on the second receiver for digitizing the signal received by the second receiver;

    f) a first converter on the first receiver for converting the signal digitized in step (d) to a complex-valued signal x[n];

    g) a second converter on the second receiver for converting the signal digitized in step (e) to a complex-valued signal y[k];

    h) a second transmitter on said first receiver for transmitting x[n], a location (x1, y1, z1) and a velocity (vx1, vy1, vz1) of the first receiver at the time that the first receiver started to receive the signal transmitted by the first transmitter;

    i) a third transmitter on said second receiver for transmitting y[k], a location (x2, y2, z2) and a velocity (vx2, vy2, vz2) of the second receiver at the time that the second receiver started receiving the signal transmitted by the first transmitter;

    j) a processor for receiving transmissions from the second transmitter and the third transmitter; and

    k) a central processing unit on said processor for determining a difference in radial velocities v0 of the first receiver and the second receiver relative to the first transmitter at times when the signal transmitted by the first transmitter started to be received by the first receiver and the second receiver and a delay time expressed in samples by y0 that represents a difference between the times that the signal transmitted by the first transmitter started to be received by the first receiver and the second receiver and for determining the location of the first transmitter (x0, y0, z0) by solving the following three equations for (x0, y0, z0);

    γ

    0
    =((x2-x0)2+(y2-y0)2+(z2-z0)2-(x1-x0)2+(y1-y0)2+(z1-z0)2)/(c



    Δ

    )
    ;





    v0=((x2-x0)

    vx



    2
    +(y2-y0)

    vy



    2
    +(z2-z0)

    vz



    2
    )
    /((x2-x0)2+(y2-y0)2+(z2-z0)2)
    )
    -((x1-x0)

    vx



    1
    +(y1-y0)

    vy



    1
    +(z1-z0)

    vz



    1
    )
    /((x1-x0)2+(y1-y0)2+(z1-z0)2)
    )
    ;


    r=√

    {square root over (x02+y02+z02)},where Δ

    is a sampling interval, c is a speed of light, (x2, y2, z2) is a position of the second receiver at the time that the signal transmitted by the first transmitter started to be received by the second receiver, (vx2, vy2, vz2) is a velocity of the second receiver at the time that the signal transmitted by the first transmitter started to be received by the second receiver, and r is a radius of the Earth.

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