Method for locating a concealed object
First Claim
1. A method of detecting anomalies in a microwave penetrable material, comprising:
- transmitting a microwave signal that is stepped over a plurality of frequencies, said microwave signal being transmitted at each of a plurality of positions in said microwave penetrable material;
receiving a plurality of reflections for said plurality of frequencies at each of said plurality of positions, each of said plurality of reflections having a magnitude and a phase and a time delay;
producing a complex target data vector from said plurality of reflections at each of said plurality of positions;
producing a complex reference data vector for each of said plurality of positions;
comparing said complex target data vector with said complex reference data vector for producing a response signal at each of said plurality of positions; and
detecting said anomalies in said microwave penetrable material from changes in said response signal for each of said plurality of positions.
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Accused Products
Abstract
Apparatus and methods are disclosed for detecting anomalies in microwave penetrable material that may be used for locating plastic mines or pipes underneath the ground. A transmitter is positioned at a plurality of different positions above the ground. A microwave signal is transmitted that is stepped over a plurality of frequencies. At each position, a plurality of reflections are received corresponding to each of the plurality of frequencies that were transmitted. A complex target vector may be produced at each position that contains complex values corresponding to magnitude, phase, and time delay for each of the plurality of reflections received at that location. A complex reference data vector may be produced, either based on predetermined values or based on data from the received plurality of reflections. A comparison is made between the complex target vector and the complex reference data vector to produce a channel vector. In one embodiment, an operator may be applied to the channel vector such as a complex filter matrix or to add a complex conjugate. A response signal is produced and anomalies are detected by variations in the response signal with respect to the plurality of positions.
60 Citations
52 Claims
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1. A method of detecting anomalies in a microwave penetrable material, comprising:
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transmitting a microwave signal that is stepped over a plurality of frequencies, said microwave signal being transmitted at each of a plurality of positions in said microwave penetrable material;
receiving a plurality of reflections for said plurality of frequencies at each of said plurality of positions, each of said plurality of reflections having a magnitude and a phase and a time delay;
producing a complex target data vector from said plurality of reflections at each of said plurality of positions;
producing a complex reference data vector for each of said plurality of positions;
comparing said complex target data vector with said complex reference data vector for producing a response signal at each of said plurality of positions; and
detecting said anomalies in said microwave penetrable material from changes in said response signal for each of said plurality of positions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 21)
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9. A method of detecting anomalies in a microwave penetrable material, comprising the steps of:
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transmitting a microwave signal that is stepped over a plurality of frequencies, said microwave signal being transmitted at each of a plurality of positions in said microwave penetrable material;
receiving a plurality of reflections for said plurality of frequencies at each of said plurality of positions, each of said plurality of reflections having a magnitude and a phase and a time delay;
producing a complex target data vector for each of said plurality of positions;
producing a complex reference data vector;
comparing said complex reference data vector with respect to each said complex target data vector to produce a complex channel vector for said plurality of frequencies at each of said plurality of positions;
producing a complex filter matrix, said complex filter matrix being a least squares operator;
operating on said complex channel vector with said complex filter matrix to obtain a response signal for each of said plurality of positions; and
detecting said anomalies in said microwave penetrable material from changes in said response signal for each of said plurality of positions. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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22. A method of detecting anomalies in microwave penetrable material, comprising:
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transmitting a microwave signal that is stepped over a plurality of frequencies, said microwave signal being transmitted at each of a plurality of positions in said microwave penetrable material;
receiving a plurality of reflections for said plurality of frequencies at each of said plurality of positions, each of said plurality of reflections having a complex impedance with a real part and an imaginary part;
producing a complex impedance vector from said real part and said imaginary part of said plurality of reflections at each of said plurality of positions;
producing a complex expectation vector for said plurality of reflections at each of said plurality of positions;
comparing said complex expectation vector with respect to said complex impedance vector at each of said plurality of frequencies to obtain a signal for each of said plurality of positions; and
detecting said anomalies in said microwave penetrable material from changes in values of said signal at each of said plurality of positions. - View Dependent Claims (23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 38, 39, 40)
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28. A method of detecting anomalies in a microwave penetrable material, comprising the steps of:
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transmitting a microwave signal that is stepped over a plurality of frequencies, said microwave signal being transmitted at each of a plurality of positions in said microwave penetrable material;
receiving a plurality of reflections for said plurality of frequencies at each of said plurality of positions, each of said plurality of reflections having a magnitude and a phase and a time delay;
utilizing said plurality of reflections to produce a complex target data vector for each of said plurality of positions;
producing a complex reference data vector;
comparing said complex reference data vector with respect to each said complex target data vector to produce a complex channel vector with respect to said plurality of frequencies for each of said plurality of positions;
adding a complex conjugate of said complex channel vector to said complex channel vector for each of said plurality of frequencies to form a conjugate symmetric complex channel vector;
taking an inverse Fourier transform of said conjugate symmetric complex channel vector to produce an impulse function to indicate said anomalies in said microwave penetrable material.
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37. A method of detecting anomalies in a microwave penetrable material, comprising the steps of:
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transmitting a microwave signal that is stepped over a plurality of frequencies, said microwave signal being transmitted at each of a plurality of positions in said microwave penetrable material;
receiving a plurality of reflections for said plurality of frequencies at each of said plurality of positions, each of said plurality of reflections having a magnitude and a phase and a time delay;
utilizing said plurality of reflections to produce a complex target data vector for each of said plurality of positions;
providing a theoretical reference signal;
comparing said theoretical reference signal to said complex target data vector for each of said plurality of frequencies at each of said plurality of positions to produce an error signal; and
detecting said anomalies in said microwave penetrable material from changes in values of said error signal at each of said plurality of positions.
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41. A method of detecting anomalies in microwave penetrable material, comprising:
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transmitting a microwave signal that is stepped over a plurality of frequencies, said microwave signal being transmitted at each of a plurality of positions in said microwave penetrable material;
receiving a plurality of reflections for said plurality of frequencies at each of said plurality of positions, determining a complex reference signal;
determining a complex antenna impedance for each of said plurality of reflections at each of said plurality of positions;
comparing said complex reference signal with said complex antenna impedance for each of said plurality of reflections at each of said plurality of positions to produce a complex difference signal for each of said plurality of reflections at each of said plurality of positions;
amplifying said complex difference signal for respective of said plurality of reflections at each of said plurality of positions to produce an amplified complex difference signal;
taking a Fourier transform of said complex difference signal to thereby produce a response signal; and
detecting said anomalies in said microwave penetrable material from changes in said response signal with respect to each of said plurality of positions. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51)
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52. A method of detecting anomalies in microwave penetrable material, comprising:
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transmitting a microwave signal that is stepped over a plurality of frequencies, said microwave signal being transmitted at each of a plurality of positions into said microwave penetrable material;
utilizing one or more accelerometers to measure location information for each of said plurality of positions;
receiving a plurality of reflections for said plurality of frequencies at each of said plurality of positions;
producing a complex target data vector at each of said plurality of positions;
producing a complex reference data vector for each of said plurality of positions;
comparing said complex target data vector with said complex reference data vector for producing a response signal at each of said plurality of positions; and
detecting said anomalies in said microwave penetrable material from changes in said response signal for each of said plurality of positions.
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Specification