System transmitting and receiving digital and analog information for use in locating concealed conductors

• US 5,264,795 A
• Filed: 06/18/1990
• Issued: 11/23/1993
• Est. Priority Date: 06/18/1990
• Status: Expired due to Fees

• Current Assignee: Charles Machine Works Incorporated The
• Original Assignee: Charles Machine Works Incorporated The
• Inventors: Rider, Alan J.
• Primary Examiner(s): Strecker, Gerard R.
• Assistant Examiner(s): EDMONDS, WARREN
• Application Number:
  US07/539,851
• Time in Patent Office: 1,254 Days
• Field of Search: 324/66, 324/67, 324/326-329, 455/234, 455/239, 455/40
• US Class Current: 324/326
• CPC Class Codes: E21B 47/0232 at least one of the energy sources or one of the detectors being located on or above the ground surface
• CPC Class Codes: G01V 3/06 using ac

Abstract

An improved locator system is provided which transmits digital and analog information over an electromagnetic field that is radiating from an underground source. The locator system includes a transmitter that modulates its output signal by turning its output signal on and off in response to a sequence of digital words. The transmitter also modulates an analog signal onto the transmitted signal. The modulated analog signal can include an audio frequency or voice signal. The improved locator system also includes a receiver that senses and detects the transmitted digital or analog signal impressed on the radiated electromagnetic field. The receiver also demodulates the transmitted audio frequency signal and provides an audio output signal to an operator.

Claims

1. A locator system for use in locating a fixed object permanently buried underground by detecting an electromagnetic field radiated from said fixed object, and receiving and processing communication information provided over said radiated electromagnetic field, said system comprising:

a generator for generating electrical energy adapted for locating said fixed object when radiated therefrom;

means for encoding a sequence of digital bits comprising digital data on said electrical energy;

means for coupling the electrical energy encoded with said digital data to said fixed object so that said fixed object radiates an encoded electromagnetic field;

means for detecting said radiated electromagnetic field including said encoded digital data at a location remote from said underground object; and

means for receiving and processing said encoded digital data received with said electromagnetic field detected at said remote location so that locating of said fixed object and communication of said encoded digital data can be carried out by said locator system.

2. The locator system according to claim 1 further including a circuit for providing operating status information concerning the locator system, wherein said operating status information defines said communication information.

3. The locator system according to claim 1 wherein said digital data comprises transmitter signal identification data.

4. The locator system according to claim 1 further including in said locator system prestored data identifying the locator system, and wherein said digital data comprises transmitter product identification data.

5. The locator system according to claim 1 wherein said digital data comprises receiver configuration command data.

6. The locator system according to claim 1 wherein a receiver of said locator system is responsive to said encoded digital to change a filter bandwidth from a narrow bandwidth to a wide bandwidth for receiving an analog signal.

7. The locator system according to claim 6 wherein said analog signal comprises an audio frequency signal.

8. A locator system for use in locating an underground object wherein communication information is modulated on an electromagnetic locating field radiated from said underground object, said system comprising:

multi-frequency signal generator means capable of generating a plurality of signals of different frequencies;

frequency selector means for selecting a signal from the plurality of signals generated by the multi-frequency signal generator means;

transmitting means for transmitting said selected signal to the underground object so that said underground object radiates an electromagnetic field and on detection thereof the underground object can be located;

output coupling means of said locator system for coupling said selected frequency signal to an output of said transmitting means;

output control means coupled to said output of said transmitting means for selectively controlling the electrical characteristics of said selected frequency signal so that communication information can be combined with said electromagnetic locating field;

modulating means coupled to said transmitting means for modulating said communication information onto said selected frequency signal;

radiating means coupled to said output of said transmitting means for radiating said modulated frequency signal;

sensing means for sensing the modulated signal radiated from said radiating means, said sensing means producing a second signal representative of the sensed radiated signal;

amplifying means coupled to said sensing means for amplifying said second signal from said sensing means;

gain control means coupled to said amplifying means for controlling the gain of said amplified second signal;

signal converter means coupled to an output of said amplifying means for converting said amplified second signal to an intermediate frequency signal; and

detecting means for removing said communication information from said intermediate frequency signal.

9. The locator system according to claim 8 wherein said multi-frequency signal generator means comprises a frequency synthesizer.

10. The locator system according to claim 8 wherein said frequency selector means comprises a digitally controlled switch.

11. The locator system according to claim 8 wherein said gain control means comprises a digital gain control.

12. The locator system according to claim 8 wherein said electrical characteristic comprises signal power.

13. The locator system according to claim 8 wherein said communication information comprises a sequence of digital words.

14. The locator system according to claim 8 wherein said communication information comprises an analog signal.

15. The locator system according to claim 14 wherein said analog signal comprises an audio frequency signal.

16. The locator system according to claim 8 further including a circuit for providing sensor related data for said locator system, wherein said sensor related data defines said communication information.

17. A method for use in locating an underground object by detecting a narrow band electromagnetic field radiated from said object for locating purposes, and for use in receiving and processing wide band information provided over the radiated electromagnetic field for communication purposes, said method comprising the steps of:

generating an electromagnetic field for driving the underground object with electrical energy;

encoding wide band information on said electromagnetic field to communicate the encoded information to a remote location;

encoding on the electromagnetic field a code used by a locator-receiver to switch from narrow band operation to wide band operation;

causing the underground object to radiate the electromagnetic field encoded with the code for reception by the locator-receiver;

switching locator-receiver circuits from narrow band operation to wide band operation;

radiating said electromagnetic field and said encoded wide band information, from said underground object;

receiving said radiated electromagnetic field and said encoded wide band information at the remote location so that wide band communication can be carried out; and

detecting and processing said encoded wide band information provided over said electromagnetic field at said remote location.

18. The method according to claim 17 wherein said encoded information comprises a sequence of digital words.

19. The method according to claim 17 wherein said encoded information comprises an analog signal.

20. The method according to claim 19 wherein said analog signal comprises an audio frequency voice signal.

36. The method of claim 17, further including radiating the encoded electromagnetic field from an antenna of a subterranean transmitter located in a boring device.

21. A method for use in locating the path of an object fixed underground wherein information is impressed on an electromagnetic field radiated from said underground object, the method comprising the steps of:

generating one of a plurality of different frequencies capable of being generated by a transmitter;

coupling said generated frequency to an output of the transmitter;

selectively controlling the power by which the generated frequency is transmitted by said transmitter;

modulating said information onto said generated frequency;

coupling said modulated frequency from said output of said transmitter to said fixed underground object;

radiating said modulated frequency from said fixed underground object;

moving a receiver of the radiated and modulated frequency on the surface of the ground to locate the path taken by the fixed underground object;

sensing the radiated and modulated frequency and producing a second signal representing said sensed radiated frequency;

amplifying said second signal;

controlling the gain of said amplified second signal;

converting said amplified second signal to an intermediate frequency signal; and

demodulating the modulated frequency to remove said information from said intermediate frequency signal.

22. The method according to claim 21 wherein said information comprises a sequence of digital words.

23. The method according to claim 21 wherein said information comprises an analog signal.

24. The method according to claim 23 wherein said analog signal comprises an audio frequency signal.

25. A method for use in locating the path of an object fixed underground, wherein information is impressed on an electromagnetic field radiated from said underground object, the method comprising the steps of:

generating a subset of different frequencies from a first plurality of different available frequencies;

coupling each frequency of said subset to a different output of a transmitter having a plurality of outputs;

modulating said information onto said subset of frequencies;

radiating at least one of said modulated frequencies from said underground object;

sensing said at least one of the radiated frequencies and producing a second signal representing said sensed radiated frequency;

amplifying said second signal;

controlling the gain of said amplified second signal;

converting said amplified second signal to an intermediate frequency signal; and

removing said information from said intermediate frequency signal.

26. A transmitter for use in a system for locating an object fixed underground, and wherein information is impressed on an electromagnetic field radiated from the underground object, said transmitter comprising:

a programmable multi-frequency signal generator adapted for generating a plurality of signals of different frequencies;

programming means for programming the signal generator to generate at least a first signal from the plurality of signals;

transmitting means receiving the signal generated by the signal generator for transmitting said generated signal;

coupling means for coupling said generated signal from the signal generator to said transmitting means;

modulating means coupled to said transmitting means for modulating said information onto said selected generated signal; and

transmitter output means coupled to said output of said transmitting means for coupling the modulated and transmitted signal to said underground fixed object.

34. The method of claim 26, further including generating a frequency with a frequency synthesizer for tuning a filter to detect said carrier frequency, and generating a frequency by said frequency synthesizer for use in down converting the carrier frequency to a lower frequency.

27. A receiver for use in a system for locating an underground object, wherein information is modulated on a carrier signal radiated from said underground object as an electromagnetic field, said receiver comprising:

means for sensing a carrier frequency of the radiated electromagnetic field and distinguishing the carrier frequency from other carrier frequencies receivable by the receiver;

detecting means for detecting the sensed carrier frequency and information modulated on the sensed carrier frequency and for producing a signal representing said detected sensed carrier frequency;

amplifying means coupled to said detecting means for amplifying said detected carrier frequency;

gain control means coupled to said amplifying means for controlling the gain of said amplifying means based on the amplitude of the detected carrier frequency;

signal converter means coupled to an output of said amplifying means and responsive to the means for detecting a carrier frequency for converting said amplified detected carrier frequency to an intermediate frequency signal; and

means for demodulating said modulated information from said intermediate frequency amplified signal.

37. The receiver of claim 27, wherein said detector detects one of a plurality of different carrier frequencies by being digitally tuned by a frequency synthesizer, said frequency synthesizer also generating a frequency for use by said signal converter for down converting said carrier frequency to a lower frequency.

28. A method for use with a transmitter for locating an underground object wherein information is modulated on a carrier frequency that is radiated from said underground object as an electromagnetic field, said method comprising the steps of:

generating a carrier frequency signal with a multi-frequency generator;

modulating the carrier frequency signal at one time with a digital signal to condition a locator receiver to operate compatibly with the transmitter, and modulating the carrier frequency signal at a different time with an analog signal;

coupling said modulated carrier frequency signal to said transmitter;

coupling said modulated carrier frequency signal from said output of said transmitter to said underground object with an output coupler; and

radiating said modulated carrier frequency signal from said underground object as the electromagnetic field.

38. The method of claim 28, further including radiating the modulated carrier frequency from an antenna of a subterranean transmitter located in a boring device.

29. A method for use with a receiver for locating an underground object, wherein information is modulated on a carrier signal and radiated from said underground object as an electromagnetic signal, said method comprising the steps of:

detecting the electromagnetic signal and the information modulated thereon as radiated from said underground object and producing a detected signal representing said detected modulated carrier signal;

amplifying said detected modulated carrier signal;

controlling the amplitude of said amplified detected modulated carrier signal;

converting said amplified detected modulated carrier signal to an intermediate frequency signal; and

removing the modulated information from said intermediate frequency signal and processing the removed modulated information to activate receiver circuits in response thereto.

30. A locator system for use in locating an underground object, comprising:

a transmitter for transmitting an electromagnetic signal to the underground object and receiver means for receiving said electromagnetic signal radiated from the underground object to determine a location of the underground object;

means in the transmitter for generating data signals identifying a type of said transmitter;

said transmitter transmitting said data signals so as to be coupled through the underground object and radiated as electromagnetic data energy therefrom; and

means in said receiver means for receiving said electromagnetic data energy and extracting said data signals, and means responsive to the data signals for reconfiguring circuits of the receiver means so that the receiver means functions compatibly with the transmitter in receiving the radiated electromagnetic signal and locating said underground object.

31. The locator system according to claim 30 wherein said identification data identifies the underground object being located.

32. The locator system according to claim 30 wherein said identification data identifies the type of transmitter from which the identification data originated.

33. The locator system according to claim 32 wherein said receiving means includes means responsive to said identification data, for reconfiguring the receiver to operate with the identified type of transmitter.

35. The locator system according to claim 30, further including in combination a subterranean boring device having incorporated therein said transmitter.

39. A locator system for use in locating an underground object wherein communication information is impressed on an electromagnetic field radiated from said underground object, said system comprising:

a transmitter, including;

multi-frequency signal generator means for generating a first plurality of signals of different carrier frequencies;

signal selector means for selecting a second plurality of signals from said first plurality of signals generated by the multi-frequency signal generator means;

transmitting means for transmitting said selected second plurality of signals;

output coupling means for coupling each signal of said selected second plurality of signals from the signal selector means to a different output of a plurality of outputs of said transmitting means;

output control means coupled to said plurality of outputs of said transmitting means for selectively controlling electrical characteristics of said selected output signals;

modulating means coupled to said transmitting means for modulating said communication information onto said selected second plurality of signals;

coupling means coupled to at least one of said plurality of outputs of said transmitting means for coupling at least one of said modulated signals to said underground object so that said underground object radiates an electromagnetic field for location purposes and radiates said communication information for communication purposes;

a receiver, including,

sensing means for sensing at least one of the radiated signals radiated from said underground object and producing a second signal representing said sensed radiated signal;

amplifying means coupled to said sensing means for amplifying said second signal from said sensing means;

gain control means coupled to said amplifying means for controlling the gain of said amplified second signal;

signal converter means coupled to an output of said amplifying means for converting said amplified second signal to an intermediate frequency signal; and

detecting means for removing said communication information from said intermediate frequency signal.

40. A method of providing communications from a transmitter transmitting a carrier to an underground conductor, to a locator receiver receiving an electromagnetic carrier radiated from the underground conductor, said method comprising the steps of:

modulating by the transmitter communication information on the carrier and coupling the modulated carrier to the underground conductor for radiation of a corresponding modulated electromagnetic carrier;

said modulation being carried out by modulating the carrier with a multi-bit word where different bit configurations of the word represent different communication information transmitted to the receiver via the underground conductor; and

demodulating the multi-bit word by the receiver and decoding the bits of the multi-bit word to determine an action to be taken by the locator receiver.

41. The method of claim 40, further including modulating a multi-bit command code on the carrier;

and

decoding the multi-bit command code by the locator receiver and reconfiguring the locator receiver from one mode of operation to a different mode of operation.

42. The method of claim 41, wherein said reconfiguring step comprises changing the locator receiver from a mode for locating an underground conductor to a mode for communicating audio signals from the transmitter to the locator receiver.

43. The method of claim 41, wherein said reconfiguring step comprises displaying on a visual display an identification of a carrier frequency transmitted by the transmitter so that receiver circuits can be reconfigured for receiving the carrier frequency identified.

44. The method of claim 40, further including decoding a multi-bit word having N+M bits, wherein an N-bit portion of the word identifies a function to be carried out by an M-bit portion of the word.

45. The method of claim 44, further including decoding the N-bits into plural different categories of information processed by the locator receiver.

46. The method of claim 45, further including decoding the M-bits to define a product code identifying a particular type of transmitter transmitting signals received by the locator receiver.

47. The method of claim 45, further including decoding the M-bits to define an identification code for identifying different transmitters of signals receivable by the locator receiver.

48. The method of claim 45, further including decoding the M-bits to define an angular orientation of an underground boring tool.

49. The method of claim 45, further including decoding the M-bits to define an electric field strength of a signal transmitted.

50. The method of claim 45, further including decoding the M-bits to define a boring tool temperature.

51. The method of claim 45, further including decoding the M-bits to define a mode of locator receiver operation, and reconfiguring the locator receiver to operate in a manner compatible with a particular type of transmitter transmitting the signal to the underground conductor.