Electromagnetic pipe mapper for accurate location and depth determination

• US 5,640,092 A
• Filed: 07/26/1994
• Issued: 06/17/1997
• Est. Priority Date: 09/27/1990
• Status: Expired due to Fees

• Current Assignee: Bryon Smith, David W. White (David White), Motazed, Behnam
• Original Assignee: Bryon Smith, David W. White (David White), Motazed, Behnam
• Inventors: White, David, Motazed, Behnam, Smith, Bryon
• Primary Examiner(s): Strecker, Gerard R.
• Application Number:
  US08/280,706
• Time in Patent Office: 1,057 Days
• Field of Search: 324/67, 324/207.11, 324/207.17, 324/207.26, 324/232, 324/233, 324/247, 324/326, 324/329, 324/334, 324/335, 324/520, 324/529, 128/653.1, 128/654, 128/899
• US Class Current: 324/326
• CPC Class Codes: G01V 3/104 using several coupled or uncoupled coils G01V3/101 takes precedence

Abstract

The device comprises a target signal transmitter to induce an electromagnetic signal in the hidden object, a position reference transmitter to transmit a signal for positioning purposes, a sensor unit to detect changes in the magnetic flux of the hidden object due to the induced electromagnetic signal and the positioning signal from the position reference transmitter, and a central unit to process and display a map of the hidden object. The initial processing of the data results in a gray-scale representation of the object, but additional data processing may be performed.

Claims

1. A system for detecting hidden cylindrical objects wherein said cylindrical object is capable of carrying an induced electric current, said system comprising:

(a) a target signal transmitter connected to said cylindrical object, said target signal transmitter inducing a first electric current and a second electric current in said cylindrical object, said second electric current having a frequency greater than the frequency of said first electric current such that said second electric current acts as a timing pulse for said first electric current by occuring once each period of said first electric current, said first electric current creating a first magnetic field which emanates outward from said cylindrical object and has said cylindrical object as a center for said first magnetic field and said second electric current creating a second magnetic field which emanates outward from said cylindrical object and has said cylindrical object as a center for said second magnetic field;

(b) a position reference transmitter located near said cylindrical object, said position reference transmitter transmitting a position reference signal; and

(c) a portable mapping device comprising;

(c)(1) a sensor unit for detecting said first and second magnetic field and said position reference signal and for generating data with respect to said detected first and second magnetic field and said position reference signal, said sensor unit comprising;

(c)(1)(i) a spherical antenna mounted in said sensor unit, said spherical antenna being a solid ferrite ball with copper wire windings wound around all three orthogonal axes of said ball, said copper wire windings being tuned to the frequency of said first electric current such that said first magnetic field creates a first signal in said spherical antenna;

(c)(1)(ii) a phase signal antenna mounted in said sensor unit adjacent to said spherical antenna, said phase signal antenna being a pair of cylindrical electromagnetic antennas arranged orthogonal to one another, each of said cylindrical electromagnetic antennas being a ferrite rod with copper wire windings wound around said ferrite rod, said copper wire windings being tuned to the frequency of said second electric current such that said second magnetic field creates a second signal in said phase signal antenna;

(c)(1)(iii) a position reference receiver means for receiving said position reference signal, said position reference receiver means mounted in said sensor unit, said position reference receiver means creating a third signal after receiving said position reference signal;

(c)(1)(iv) signal processing means for processing said first, second and third signals, said signal processing means mounted in said sensor unit, said signal processing means using said second signal to create an emulated first signal, said emulated first signal imitating the frequency and wave pattern of said first electric current, said signal processing means comparing the phase of said emulated first signal to the phase of said first signal to determine which side of said object said sensor unit is on and generating data from said first, second and third signals; and

(c)(2) a central unit connected to said sensor unit, said central unit comprising a computer for processing data obtained from said sensor unit and conveying to a user the location of the cylindrical object.

2. The system of claim 1 wherein said copper wire windings on said spherical antenna are tuned to the frequency of said first electric current by having said copper wire windings wound around each of said orthogonal axes about 1000 to 2000 times, and said copper wire having a gauge of about 40 to 48.

3. The system of claim 1 wherein said copper wire windings on said phase signal antenna are tuned to the frequency of said second electrical current by having said copper wire windings wound around each of said ferrite rods about 1000 to 2000 times and said copper wire having a gauge of about 36 to 40.

4. The system of claim 1 wherein the frequency of the first electric current is about 10 KHz and the frequency of the second electric current is about 100 KHz.

5. The system of claim 1 wherein said position reference transmitter is selected from the group consisting of magnetic position reference transmitter, acoustic position reference transmitter, microwave position reference transmitter and laser position reference transmitter.

6. A system for detecting hidden cylindrical objects wherein said cylindrical object is capable of carrying an induced electric current, said system comprising:

(a) a target signal transmitter connected to said cylindrical object, said target signal transmitter inducing an electric current in said cylindrical object, said electric current creating a magnetic field which emanates outward from said cylindrical object and has said cylindrical object as a center for said magnetic field, said target signal transmitter having a radio wave transmitter which transmits a radio wave having a frequency higher than said electric current such that said radio wave acts as a timing pulse for said electric current by occuring once each period of said electric current;

(b) a position reference transmitter located near said cylindrical object, said position reference transmitter transmitting a position reference signal; and

(c) a portable mapping device comprising;

(c)(1) a sensor unit for detecting said radio wave, said magnetic field and said position reference signal and for generating data with respect to said detected magnetic field, said radio wave and said position reference signal, said sensor unit comprising;

(c)(1)(i) a spherical antenna mounted in said sensor unit, said spherical antenna being a solid ferrite ball with copper wire windings wound around all three orthogonal axes of said ball, said copper wire windings being tuned to the frequency of said electric current such that said magnetic field creates a first signal in said spherical antenna;

(c)(1)(ii) a radio wave receiver mounted in said sensor unit for receiving said radio wave, said radio wave receiver creating a second signal after receiving said radio wave;

(c)(1)(iii) a position reference receiver means for receiving said position reference signal, said position reference receiver means mounted in said sensor unit, said position reference receiver creating a third signal after receiving said position reference signal;

(c)(1)(iv) signal processing means for processing said first, second and third signals, said signal processing means mounted in said sensor unit, said signal processing means using said second signal to create an emulated electric current signal, said emulated electric current signal imitating the frequency and wave pattern of said electric current, said signal processing means comparing the phase of said emulated electric current signal to the phase of said first signal to determine which side of said object said sensor unit is on and generating data from said first, second and third signals; and

(c)(2) a central unit connected to said sensor unit, said central unit comprising a computer for processing data obtained from said sensor unit and conveying to a user the location of the cylindrical object.