Device for quantitatively measuring the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields

• US 4,849,692 A
• Filed: 10/09/1986
• Issued: 07/18/1989
• Est. Priority Date: 10/09/1986
• Status: Expired due to Term

• Current Assignee: BAE Systems Plc
• Original Assignee: Ascension Technology Corporation (Roper Technologies, Inc.)
• Inventors: Blood, Ernest B.
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Snow, Walter E.
• Application Number:
  US06/917,389
• Time in Patent Office: 1,013 Days
• Field of Search: 324/207, 324/208, 342/450, 342/451, 342/452, 342/453, 340/870.31
• US Class Current: 324/207.26
• CPC Class Codes: F41G 3/225 Helmet sighting systems
• CPC Class Codes: G01B 7/004 for measuring coordinates of points
• CPC Class Codes: G01B 7/14 for measuring distance or clearance between spaced objects or spaced apertures G01B7/30 takes precedence

Abstract

A device for quantitatively measuring the relative position and orientation of two bodies in the presence of metals via measuring the position and orientation of receiving antennae with respect to transmitting antennae utilizing direct current electromagnetic field signals is hereby disclosed. The transmitting and receiving components of the instant device consist of two or more separate transmitting antennae of known position and orientation with respect to each other. Each transmitting antenna is driven one at a time by a pulsed, direct current signal. The receiving antennae measure the values of transmitted direct current magnetic fields one dimension at a time and those of the Earth'"'"'s magnetic field as well, one dimension at a time. A computer is used to control circuit elements of the transmitting and receiving elements of the device and likewise functions to convert received signals into position and orientation outputs after having first effected a subtraction out of the overall value of the Earth'"'"'magnetic field.

Claims

1. A device for quantitatively measuring the relative position and orientation of receiving antennae with respect to transmitting antennae serving to measure the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields, comprising:

(a) Transmitting means for transmitting direct current magnetic fields;

(b) Receiving means for receiving said transmitted direct current magnetic fields;

(c) Means for supplying direct current electrical signals to said transmitting means for creating said transmitted direct current magnetic fields;

(d) Receiver Electronics for measuring, and converting output signals from said receiving means into position and orientation measurements consisting of a programmed computer, an analog to digital converter, a programmable gain signal amplifier, a filter, a differential amplifier, a digital to analog converter and a multiplexer switching unit for receiving signals one at a time from the antennae of said receiving means which said multiplexer switching unit, under the control of said programmed computer, passes a selected one of said received signals to said differential amplifier where the Earth'"'"'s magnetic field signal, which was measured by said receiver and read into said computer when the said transmitter was shut off, is outputted from said computer to said digital to analog converter where said digital to analog converter converts the digital representation of the Earth'"'"'s magnetic field signal strength to an analog representation which goes to said differential amplifier, where the said Earth'"'"'s field signal is subtracted from said selected received signal whereupon the output from said differential amplifier then goes to said filter for removing noise from the said selected received signal which then passes said filtered signal to said programmable gain signal amplifier, which, under the control of said programmed computer, increases said received filtered signal'"'"'s level to a value appropriate to the signal level limits of said analog to digital converter which converts the said amplified received filtered signal to a digital representation that is then passed to said programmed computer.

2. A device for quantitatively measuring the relative position and orientation of receiving antennae with respect to transmitting antennae serving to measure the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields, comprising:

(a) A transmitter for transmitting direct current magnetic fields consisting of a core and a multiplicity of roughly orthogonal antenna axis wire windings;

(b) Receiving means for receiving said transmitted direct current magnetic fields;

(c) Transmitter electronics consisting of a programmed computer, a digital-analog signal converter, a Multiplexer actuated by said programmed computer in receiver electronics and simultaneously by said converter and one direct current power source applied to the wire windings of each transmitter antenna axis to generate a magnetic field actuated in turn by said Multiplexer;

(d) Receiver Electronics for measuring, and converting output signals from said receiving means into position and orientation measurements consisting of said programmed computer, an analog to digital converter, a programmable gain signal amplifier, a filter, a differential amplifier, a digital to analog converter and a multiplexer switching unit for receiving signals one at a time from the antennae of said receiving means which said multiplexer switching unit under the control of said programmed computer, passes a selected one of said received signals to said differential amplifier where the Earth'"'"'s magnetic field signal, which was measured by said receiver and read into said computer when the said transmitter was shut off, is outputted from said computer to said digital to analog converter where said digital to analog converter converts the digital representation of the Earth'"'"'s magnetic field signal strength to an analog representation which goes to said differential amplifier, where the said Earth'"'"'s field signal is subtracted from said selected received signal whereupon the output from said differential amplifier then goes to said filter for removing noise from the said selected received signal which then passes said filtered signal to said programmable gain signal amplifier, which, under the control of said programmed computer, increases said filtered signal'"'"'s level to a value appropriate to the signal level limits of said analog to digital converter which converts the said amplified received filtered signal to digital representation that is then passed to said programmed computer.

3. A device for quantitatively measuring the relative position and orientation of receiving antennae with respect to transmitting antennae serving to measure the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields, comprising:

(a) A transmitter for transmitting direct current magnetic fields consisting of a core and a multiplicity of roughly orthogonal antenna axis wire windings;

(b) Receiving means for receiving said transmitted direct current magnetic fields;

(c) Means for supplying direct current electrical signals to said transmitting means for creating said transmitted direct current magnetic fields;

(d) Receiver Electronics for measuring, and converting output signals from said receiving means into position and orientation measurements consisting of a programmed computer, an analog to digital converter, a programmable gain signal amplifier, a filter, a differential amplifier, a digital to analog converter and a multiplexer switching unit for receiving signals one at a time from the antennae of said receiving means which said multiplexer switching unit, under the control of said programmed computer, passes a selected one of said received signals to said differential amplifier where the Earth'"'"'s magnetic field signal, which was measured by said receiver and read into said computer when the said transmitter was shut off, is outputted from said computer to said digital to analog converter where said digital to analog converter converts the digital representation of the Earth'"'"'s magnetic field signal strength to an analog representation which goes to said differential amplifier, where the said Earth'"'"'s magnetic field signal is subtracted from said selected received signal whereupon the output from said differential amplifier then goes to said filter for removing noise from the said selected received signal which then passes said filtered signal to said programmable gain signal amplifier, which, under the control of said programmed computer, increases said received filtered signal'"'"'s level to a value appropriate to the signal level limits of said analog to digital converter which converts the said amplified received filtered signal to a digital representation that is then passed to said programmed computer.

4. A device for quantitatively measuring the relative position and orientation of receiving antennae with respect to transmitting antennae serving to measure the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields, comprising:

(a) Transmitting means for transmitting direct current magnetic fields;

(b) Receiving means for receiving said transmitted direct current magnetic fields consisting of a multiplicity of roughly orthogonal antennae axes that are sensitive to transmitted direct current magnetic fields;

(c) Means for supplying direct current electrical signals to said transmitting means for creating said transmitted direct current magnetic fields;

(d) Receiver Electronics for measuring, and converting output signals from said receiving means into position and orientation measurements consisting of a programmed computer, an analog to digital converter, a programmable gain signal amplifier, a filter, a differential amplifier, a digital to analog converter and a multiplexer switching unit for receiving signals one at a time from the antennae of said receiving means which said multiplexer switching unit, under the control of said programmed computer, passes a selected one of said receiving signals to said differential amplifier where the Earth'"'"'s magnetic field signal, which was measured by said receiver and read into said computer when the said transmitter was shut off, is outputted from said computer to said digital to analog converter where said digital to analog converter converts the digital representation of the Earth'"'"'s magnetic field signal strength to an analog representation which goes to said differential amplifier, where the said Earth'"'"'s magnetic field signal is subtracted from said selected received signal whereupon the output from said differential amplifier then goes to said filter for removing noise from the said selected received signal which then passes said filtered signal to said programmable gain signal amplifier, which, under the control of said programmed computer, increases said received filtered signal'"'"'s level to a value appropriate to the signal level limits of said analog to digital converter which converts the said amplified received filtered signal to a digital representation that is then passed to said programmed computer.

5. A device for quantitatively measuring the relative position and orientation of receiving antennae with respect to transmitting antennae serving to measure the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields, comprising:

(a) Transmitting means for transmitting direct current magnetic fields;

(b) Receiving means for receiving said transmitted direct current magnetic fields;

(c) Transmitter electronics consisting of a programmed computer, a digital-analog signal converter, a Multiplexer actuated by said programmed computer in receiver electronics and simultaneously by said converter and one direct current power source applied to the wire windings of each transmitter antenna axis to generate a magnetic field actuated in turn by said Multiplexer;

(d) Receiver Electronics for measuring and converting output signals from said receiving means into position and orientation measurements consisting of said programming computer, an analog to digital converter, a programmable gain signal amplifier, a filter, a differential amplifier, a digital to analog converter and a multiplexer switching unit for receiving signals one at a time from the antennae of said receiving means which said multiplexer switching unit, under the control of said programmed computer, passes a selected one of said received signals to said differential amplifier where the Earth'"'"'s magnetic field signal, which was measured by said receiver and read into said computer when the said transmitter was shut off, is outputted from said computer to said digital to analog converter where said digital to analog converter converts the digital representation of the Earth'"'"'s magnetic field signal strength to an analog representation which goes to said differential amplifier, where the said Earth'"'"'s magnetic field signal is subtracted from said selected received signal whereupon the output from said differential amplifier then goes to said filter for removing noise from the said selected received signal which then passes said filtered signal to said programmable gain signal amplifier, which, under the control of said programmed computer, increases said received filtered signal'"'"'s level to a value appropriate to the signal level limits of said analog to digital converter which converts the said amplified received filtered signal to a digital representation that is then passed to said programmed computer.

6. A device for quantitatively measuring the relative position and orientation of receiving antennae with respect to transmitting antennae serving to measure the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields, comprising:

(a) Transmitting means for transmitting direct current magnetic fields;

(b) Receiving means for receiving said transmitted direct current magnetic fields consisting of a multiplicity of roughly orthogonal antennae axes that are sensitive to transmitted direct current magnetic fields;

(c) Transmitter electronics consisting of a programmed computer, a digital-analog signal converter, a Multiplexer actuated by said programmed computer in receiver electronics and simultaneously by said converter and one direct current power source applied to the wire windings of each transmitter antenna axis to generate a magnetic field actuated in turn by said Multiplexer;

(d) Receiver Electronics for measuring and converting output signals from said receiving means into position and orientation measurements consisting of said programmed computer, an analog to digital converter, a programmable gain signal amplifier, a filter, a differential amplifier, a digital to analog converter and a multiplexer switching unit for receiving signals one at a time from the antenna of said receiving means which said multiplexer switching unit, under the control of said programmed computer, passes a selected one of said receiving signals to said differential amplifier where the Earth'"'"'s magnetic field signal, which was measured by said receiver and read into said computer when the said transmitter was shut off, is outputted from said computer to said digital to analog converter where said digital to analog converter converts the digital representation of the Earth'"'"'s magnetic field signal strength to an analog representation which goes to said differential amplifier, where the said Earth'"'"'s magnetic field signal is subtracted from said selected received signal whereupon the output from said differential amplifier then goes to said filter for removing noise from the said selected received signal which then passes said filtered signal to said programmable gain signal amplifier, which, under the control of said programmed computer, increases said received filtered signal'"'"'s level to a value appropriate to the signal level limits of said analog to digital converter which converts the said amplified received filtered signal to a digital representation that is then passed to said programmed computer

7. A device for quantitatively measuring the relative position and orientation of receiving antennae with respect to transmitting antennae serving to measure the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields, comprising:

(a) A transmitter for transmitting direct current magnetic fields consisting of a core and a multiplicity of roughly orthogonal antenna axis wire windings;

(b) Receiving means for receiving said transmitted direct current magnetic fields consisting of a multiplicity of roughly orthogonal antennae axes that are sensitive to transmitted direct current magnetic fields;

(c) Means for supplying direct current electrical signals to said transmitting means for creating said transmitted direct current magnetic fields;

(d) Receiver Electronics for measuring, and converting output signals from said receiving means into position and orientation measurements consisting of a programmed computer, an analog to digital converter, a programmable gain signal amplifier, a filter, a differential amplifier, a digital to analog converter and a multiplexer switching unit for receiving signals one at a time from the antennae of said receiving means which said multiplexer switching unit, under the control of said programmed computer, passes a selected one of said received signals to said differential amplifier where the Earth'"'"'s magnetic field signal, which was measured by said receiver and read into said computer when the said transmitter was shut off, is outputted from said computer to said digital to analog converter where said digital to analog converter converts the digital representation of the Earth'"'"'s magnetic field signal strength to an analog representation which goes to said differential amplifier, where the said Earth'"'"'s field signal is subtracted from said selected received signal whereupon the output from said differential amplifier then goes to said filter for removing noise from the said selected received signal which then passes said filtered signal to said programmable gain signal amplifier, which, under the control of said programmed computer, increases said received filtered signal'"'"'s level to a value appropriate to the signal level limits of said analog to digital converter which converts the said amplified received filtered signal to a digital representation that is then passed to said programmed computer.

8. A device for quantitatively measuring the relative position and orientation of receiving antennae with respect to transmitting antennae serving to measure the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields, comprising:

(a) A transmitter for transmitting direct current magnetic fields consisting of a core and multiplicity of roughly orthogonal antenna axis wire windings;

(b) Receiving means for receiving said transmitted direct current magnetic fields consisting of a multiplicity of roughly orthogonal antennae axes that are sensitive to transmitted direct current magnetic fields;

(c) Transmitter electronics consisting of a programmed computer, a digital-analog signal converter, a Multiplexer actuated by said programmed computer in receiver electronics and simultaneously by said converter and one direct current power source applied to the wire windings of each transmitter antenna axis to generate a magnetic field actuated in turn by said Multiplexer;

(d) Receiver Electronics for measuring and converting output signals from said receiving means into position and orientation measurements consisting of said programmed computer, an analog to digital converter, a programmable gain signal amplifier, a filter, a differential amplifier, a digital to analog converter and a multiplexer switching unit for receiving signals one at a time from the antennae of said receiving means which said multiplexer switching unit, under the control of said programmed computer, passes a selected one of said received signals to said differential amplifier where the Earth'"'"'s magnetic field signal, which was measured by said receiver and read into said computer when the said transmitter was shut off, is outputted from said computer to said digital to analog converter where said digital analog converter converts the digital representation of the Earth'"'"'s magnetic field signal strength to an analog representation which goes to said differential amplifier, where the said Earth'"'"'s field signal is subtracted from said selected received signal whereupon the output from said differential amplifier then goes to said filter for removing noise from the said selected received signal which then passes said filtered signal to said programmable gain signal amplifier, which, under the control of said programmed computer, increases said received filtered signal'"'"'s level to a value appropriate to the signal level limits of said analog to digital converter which converts the said amplified received filtered signal to a digital representation that is then passed to said programmed computer.

9. A device for quantitatively measuring the relative position and orientation of receiving antennae with respect to transmitting antennae serving to measure the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields, comprising:

(a) Transmitting means for transmitting direct current magnetic fields;

(b) Receiving means for receiving said transmitted direct current magnetic fields;

(c) Means for supplying direct current electrical signals to said transmitting means for creating said transmitted direct current magnetic fields;

(d) Receiver electronics for controlling circuit elements of said transmitting and receiving means, measuring received signals and converting output signals from said receiving means into position and orientation measurements consisting of a programmed computer, an analog to digital converter, a programmable gain signal amplifier, a filter, a differential amplifier, a digital to analog converter and a multiplexer switching unit for receiving signals one at a time from the antennae of said receiving means which said multiplexer switching unit, under the control of said programmed computer, passes a selected one of said received signals to said differential amplifier where the Earth'"'"'s magnetic field signal, which was measured by said receiver and read into said computer when the said transmitter was shut off, is outputted from said computer to said digital to analog converter where said digital to analog converter converts the digital representation of the Earth'"'"'s magnetic field signal strength to an analog representation which goes to said differential amplifier, where the said Earth'"'"'s field signal is subtracted from said selected received signal whereupon the output from said differential amplifier then goes to said filter for removing noise from the said selected received signal which then passes said filtered signal to said programmable gain signal amplifier, which, under the control of said programmed computer, increases said received filtered signal'"'"'s level to a value appropriate to the signal level limits of said analog to digital converter which converts the said amplified received filtered signal to a digital representation that is then passed to said programmed computer.

10. A device for quantitatively measuring the relative position and orientation of receiving antennae with respect to transmitting antennae serving to measure the relative position and orientation of two bodies in the presence of metals utilizing direct current magnetic fields, comprising:

(a) A transmitter for transmitting direct current magnetic fields consisting of a core and a multiplicity of roughly orthogonal antenna axis wire windings;

(b) Receiving means for receiving said transmitted direct current magnetic fields;

(c) Transmitter electronics consisting of a programmed computer, a digital-analog signal converter, a multiplexer actuated by said programmed computer in receiver electronics and simultaneously by said converter and one direct current power source applied to the wire windings of each transmitter antenna axis to generate a magnetic field actuated in turn by said multiplexer;

(d) Receiver electronics for controlling circuit elements of said transmitter and said receiving means, measuring received signals and converting output signals from said receiving means into position and orientation measurements consisting of a programmed computer, an analog to digital converter, a programmable gain signal amplifier, a filter, a differential amplifier, a digital to analog converter and a multiplexer switching unit for receiving signals one at a time from the antennae of said receiving means which said multiplexer switching unit under the control of said programmed computer, passes a selected one of said received signals to said differential amplifier where the Earth'"'"'s magnetic field signal, which was measured by said receiver and read into said computer when the said transmitter was shut off, is outputted from said computer to said digital to analog converter where said digital to analog converter converts the digital representation of the Earth'"'"'s magnetic field signal strength to an analog representation which goes to said differential amplifier, where the said Earth'"'"'s field signal is subtracted from said selected received signal whereupon the output from said differential amplifier then goes to said filter for removing noise from the said selected received signal which then passes said filtered signal to said programmable gain signal amplifier, which, under the control of said programmed computer, increases said received filtered signal'"'"'s level to a value appropriate to the signal level limits of said analog to digital converter which converts the said amplified received filtered signal to digital representation that is then passed to said programmed computer.

11. A device for quantitatively measuring the relative position and orientation of receiving antennae with respect to transmitting antennae serving to measure the relative position and orientation to two bodies in the presence of metals utilizing direct current magnetic fields, comprising:

(a) A transmitter for transmitting direct current magnetic fields consisting of a core of multiplicity of roughly orthogonal antenna axis wire windings;

(b) A receiver for receiving said transmitted direct current magnetic fields consisting of a multiplicity of roughly orthogonal antennae axes that are sensitive to transmitted direct current magnetic fields;

(c) Transmitter electronics consisting of a programmed computer, a digital to analog signal converter, a multiplexer actuated by said computer in receiver electronics and simultaneously by said converter and one direct current power source applied to the wire windings of each transmitter antenna axis to generate a magnetic field actuated in turn by said Multiplexer;

(d) Receiver electronics for controlling circuit elements of said transmitter and said receiving means, measuring received signals and converting output signals from said receiving means into position and orientation measurements consisting of a programmed computer, an analog to digital converter, a programmable gain signal amplifier, a filter, a differential amplifier, a digital to analog converter and a multiplexer switching unit for receiving signals one at a time from the antennae of said receiving means which said multiplexer switching unit, under the control of said programmed computer, passes a selected one of said received signals to said differential amplifier, where the Earth'"'"'s magnetic field signal, which was measured by said receiver and read into said computer when the said transmitter was shut off, outputted from said computer to said digital to analog converter where said digital to analog converter converts the digital representation of the Earth'"'"'s magnetic field signal strength to an analog representation which goes to said differential amplifier, where the Earth'"'"'s field signal is subtracted from said selected received signal whereupon the output from said differential amplifier then goes to said filter for removing noise from the said selected received signal which then passes said filtered signal to said programmable gain signal amplifier, which, under the control of said programmed computer, increases said received filtered signal'"'"'s level to a value appropriate to the signal level limits of said analog to digital converter which converts the said amplified received filtered signal to a digital representation that is then passed to said programmed computer.