Distance measuring system

• US 5,298,904 A
• Filed: 08/04/1992
• Issued: 03/29/1994
• Est. Priority Date: 08/04/1992
• Status: Expired due to Fees

• Current Assignee: Kirk J. Olich
• Original Assignee: Kirk J. Olich
• Inventors: Olich, Kirk J.
• Primary Examiner(s): TUBBESING, THEODORE
• Application Number:
  US07/924,641
• Time in Patent Office: 602 Days
• Field of Search: 342/42, 342/125, 342/127, 342/103
• US Class Current: 342/42
• CPC Class Codes: A63B 2102/32 Golf
• CPC Class Codes: A63B 2220/13 Relative positions
• CPC Class Codes: G01S 13/84 for distance determination by phase measurement

Abstract

A distance measuring system which may be used on a golf course in order for a golfer to accurately measure the distance between the present lie of his golf ball and the hole toward which he is currently advancing the golf ball. A master transceiver station is portably carried by the golfer to be disposed proximate the lie of his ball for measurement purposes, and a remote transceiver system is located in or on each hole'"'"'s flag marker pole. The present system uses, as the basic measurement frequency, only the frequency of the remote carrier itself. Two separate and distinct phase measurements are made in rapid succession. The first measurement is made with the master RF carrier displaced above the remote carrier frequency by amount equal to the IF frequency, and the second measurement is made with the master carrier frequency displaced below the remote carrier frequency by the same amount. With these two phase measurements, range or distance can be measured unambiguously and accurately over a required distance of at least 300 yards for golf purposes. The phase information from the remote location is communicated to the master location by phase-locking the carriers together. This avoids the necessity of using modulated subcarriers to transmit this information. This, in turn, reduces the occupied bandwidth, simplifies the modulation-demodulation required, and reduces errors normally introduced by the subcarrier filtering processes of the prior art.

Claims

1. A distance measuring system for use on a golf course including a plurality of different and distinct, consecutively numbered holes, each hole having a unique hole number for positively identifying same, each of said holes having a flag marker associated therewith for visually identifying its corresponding unique hole number, and wherein a golfer attempts to advance a golf ball toward each of said plurality of numbered holes in consecutive order for playing a round of golf, said distance measuring system comprising:

a remote transceiver means and a master transceiver means including a master transceiver circuit means and a housing means for substantially enclosing said master transceiver circuit means, said housing means including a master antenna means for transmitting and receiving radio signals, a manually-operable means for initiating a request for a distance measurement signal, a display panel means for visually indicating the measured distance, and a means for visually indicating the unique number of the hold toward which the golfer is presently advancing his golf ball;

said master transceiver circuit means including;

a crystal oscillator means for generating a predetermined fixed reference frequency signal;

a frequency synthesizer means, including a master UHF oscillator means and a loop filter means, for converting said fixed reference frequency signal into a first desired master carrier frequency signal;

a computer means for programming said frequency synthesizer means to generate said first master carrier frequency signal at said first desired frequency;

means for operatively coupling said first master carrier frequency signal to said master antenna means for transmission to said remote transceiver means;

master mixer means for receiving a first return signal from said remote transceiver means and mixing same with said first master carrier frequency signal for producing a first frequency difference signal;

master IF amplifier means for amplifying said first frequency difference signal;

a master frequency divider circuit means for dividing down said crystal oscillator fixed frequency reference signal to produce a divided-down reference signal;

a master phase detector means having first and second inputs and a phase detector output, the first one of said inputs being operably connected to the output of said master frequency divider circuit means for inputting said divided-down reference signal thereto, and the second one of said inputs being operatively coupled to the output of said master IF amplifier means for inputting said first IF-amplified frequency difference signal thereto, the output of said phase detector means representing a first distance between the golfer'"'"'s ball and said properly numbered hole;

said computer means having an input operably connected to the output of said master phase detector means for inputting said first distance measurement signal thereto, said computer means converting said first distance measurement signal into a first digital data signal;

said remote transceiver means including;

means for operatively mounting same at said flag marker;

a remote antenna means for transmitting and receiving signals to and from said master transceiver means;

a remote UHF oscillator means for generating a fixed remote carrier frequency signal;

a remote mixer means for mixing said received first master carrier frequency signal with said remote carrier frequency signal to output a first remote difference frequency signal;

a remote IF amplifier means for amplifying said first remote difference frequency signal and outputting same;

remote digital frequency divider means for dividing down said remote carrier frequency signal to produce a remote divided-down signal;

a remote phase comparator means having first and second inputs and first and second outputs, said first input being operably connected to the output of said remote digital frequency divider means for inputting said first remote divided-down signal and said second input being operably connected to the output of said remote IF amplifier means for inputting said IF-amplifier first remote difference frequency signal thereto, said first output generating a first known phase reference signal for the remote position and said second output generating a control signal for out-of-lock detection purposes;

a remote loop filter means for filtering said first output of said remote phase comparator means said remote loop filter means and said remote UHF oscillator means forming a phase-locked loop;

a remote out-of-lock detector circuit means having an input operatively coupled to said second output of said remote phase comparator means for monitoring said control signal and for generating a predetermined sequence of plus and minus sense-switching signals whenever said phase-lock loop is in an out-of-lock state; and

sense switching means coupled to the loop filter means and to the detector circuit means for periodically switching the polarity of the output of said remote loop filter means whenever said out-of-lock detector means detects an out-of-lock condition for said phase-lock loop, and for continuing to pass said filtered first known phase reference signal to said remote UHF oscillator means for transmitting said back to said master transceiver means via said second antenna means whenever said phase-lock loop is in a locked position.

2. The distance measuring system of claim 1 wherein said computer means comprises means for providing first and second digital data signals to said frequency synthesizer means to alternately produce first and second master carrier frequency signals;

said remote transceiver means receiving said second master carrier frequency signal and outputting a second known phase reference signal for transmission back to said master transceiver means via said remote carrier frequency signal for a second distance measurement; and

said master transceiver means receiving said second known phase reference signal and producing a second measurement signal which is supplied to said computer means to resolve said ambiguity and produce a second digital data signal free from ambiguity over the required measurement distance.

3. The distance measuring system of claim 2 wherein said computer initially generates a digital data ID signal means, indicative of the unique hole identification number of the hole toward which the golfer is presently advancing his golf ball, for modulating said first master carrier frequency signal for transmission to said remote transceiver means;

said remote transceiver means further including hole identification circuit means responsive to said digital data ID signal carried by said first master carrier frequency signal for generating an enablement signal in response to a positive match between the digital data ID signal and a data-encoded signal indicative of said hole number; and

said remote UHF oscillator means being responsive to said enablement signal for generating said remote carrier frequency signal and transmitting same back to said master transceiver means for verifying that the correct remote transceiver means is being contacted for the distance measurement.

4. A digital distance measurement system for use on a conventional golf course which includes a plurality of sequentially numbered different and distinct holes, each hole being identified by a flag marker pin having a lower end portion adapted to be removeably inserted into the hole and an upper and portion adapted to be vertically positioned above said hole and further including a hole marker flag bearing a visual indication of that hole'"'"'s unique hole identification number in said sequence of holes, and wherein at least one golfer attempts to advance his golf ball toward and into each successively numbered hole to play a round of golf, said digital distance measuring system comprising:

a single matter transceiver means adapted to be positioned at least one of adjacent, abeam, and over the position of the golf ball on the course and a display means for visually indicating at least the number of the hole being approached and the measured distance from the ball to the desired hole; and

a plurality of remote transceiver means, one of said remote transceiver means for each unique, sequentially-numbered hole, each of said remote transceiver means being adapted to be operatively carried by the corresponding flag marker of said hole;

said master transceiver means including;

(1) manually operable means for generating a distance measurement request signal indicative of the need for a measurement of the distance between the present lie of the golf ball and the hole toward which the golfer is advancing;

(2) means responsive to said distance measuring request signal for generating a first master carrier frequency signal and a data signal indicative of the approached hole'"'"'s unique hole identification number; and

(3) means for transmitting said data signal to said remote transceiver means by modulating said first master carrier frequency signal therewith;

said remote transceiver means including;

(1) means responsive to the reception of said digital data signal for determining if that particular hole corresponds to the hole identified thereby, and for generating a command signal for a predetermined period of time whenever a positive identification exists;

(2) means responsive to said control signal for generating a fixed remote carrier frequency signal and transmitting same back to said master transceiver means to verify that the distance to be measured is to the proper hole;

(3) means responsive to said first master carrier frequency signal and to said remote carrier frequency signal for generating a first frequency difference signal indicative of the difference in frequency therebetween;

(4) means for dividing-down said remote carrier frequency signal to produce a remote divided-down signal;

(5) means responsive to said remote divided-down signal and said first frequency difference signal for generating a first known phase reference signal; and

(6) means for transmitting said first known phase reference signal back to said master transceiver means via said remote carrier frequency signal;

said master transceiver means further including;

(4) means responsive to said first known phase reference signal for reproducing said first frequency difference signal;

(5) means for dividing down said master carrier reference frequency signal to produce a master divided-down signal; and

(6) means responsive to said first frequency difference signal and said master divided-down signal for generating a first measurement signal indicative of the distance between the position of the golf ball on the golf course and the position of the hole toward which the golfer is currently advancing his golf ball;

said master transceiver means further including;

(7) means for reprogramming said generating means for generating a second different and distinct master carrier frequency signal; and

(8) said means for generating said master carrier frequency signals now generating said second master carrier frequency signal and transmitting same back to said remote transceiver means for a second distance measurement;

said remote transceiver means being responsive to the reception of said second master carrier frequency signal for;

(7) generating a second frequency different signal indicative of the difference in frequency between said second master carrier frequency signal and said fixed remote carrier frequency signal;

(8) comparing said second frequency difference signal and said first divided-down remote carrier frequency signal for generating a second known phase reference signal; and

(9) transmitting said second known phase reference signal back to said master transceiver means via said remote carrier frequency signal; and

wherein said master transceiver means is responsive to said second known phase reference signal for;

(9) reproducing said second frequency difference signal;

(10) generating a second measurement signal in response to said second frequency difference signal and said second divided-down master frequency reference signal, said second measurement being indicative of the measured distance as a fraction of one-half of the wavelength of said second master carrier frequency signal; and

(11) converting said second measurement signal into digital data and combining the two digital data signals to generate a final distance measurement signal equal to the actual measured distance between the location of the golf ball on the golf course and the position of the desired hole without ambiguity and to a high degree of accuracy.

5. The digital distance measuring system of claim 4 wherein said means responsive to said distance measuring request signal includes computer means for sequentially programming said transmitting means with programmed data for generating said first and second predetermined desired master carrier frequency signals, for generating said data signal indicative of the unique number of the particular hole toward which the golfer is presently advancing his golf ball, and for converting said first and second measurement signals into digital data for visually displaying the measured distance on said digital display panel means.

6. The digital data measuring system of claim 5 wherein said means for transmitting said first and second master carrier frequency signals includes:

master crystal oscillator means for generating a master reference frequency signal;

frequency synthesizer means responsive to said master reference frequency signal and to said programmed data from said computer means for generating said first and second master carrier frequency signals, respectively; and

means operably connecting the output of said frequency synthesizer means to said antenna for transmitting said first and second master carrier frequency signals, sequentially, to said remote transceiver means.

7. The digital distance measuring system of claim 6 wherein said master transmitting means further includes:

a master loop filter means for filtering the output of said frequency synthesizer means;

a master modulating means coupled to the output of said master loop filter means for modulating said first master carrier frequency signal with said data signal indicative of the desired hole identification number, and for outputting a modulated first master carrier frequency signal to said master transceiver antenna means for transmission to said remote transceiver means.

8. The digital distance measuring system of claim 7 wherein said means responsive to said first and second known phase reference signals for reproducing said first and second frequency difference signals includes:

master mixer means for sequentially mixing said first and second known phase reference signals with said first and second master carrier frequency signals, respectively, to reproduce said first and second frequency difference signals respectively;

master IF amplifier means for sequentially amplifying said first and second frequency difference signals for outputting same.

9. The digital distance measuring system of claim 8 wherein said means for dividing down said master reference frequency signal for said frequency synthesizer means includes a master digital divide-by-"n" logic circuit means for producing said first and second divided-down signals, respectively, and outputting same.

10. The digital distance measuring system of claim 9 wherein said means for generating said first and second measurement signals includes a master phase detector means having first and second inputs and an output, said master phase detector means having said first input operably connected to the output of said master digital divide-by-"n" logic circuit means for sequentially receiving said first and second divided-down signals therefrom, and said second input operably connected to the output of said master IF amplifier means for sequentially receiving said amplified first and second frequency difference signals, and said phase detector output being operatively connected to said computer means for sequentially supplying said first and second measurement signals thereto for conversion to a highly accurate, unambiguous, digital distance measurement for display on said display panel means.

11. The digital distance measuring system of claim 10 wherein said remote transceiver means further includes a remote transceiver housing means for substantially enclosing said remote transceiver means, said remote transceiver housing means being adapted to be operatively carried at least one of within and on the outside of said flag marker means, said remote transceiver housing including an antenna means for transmitting and receiving radio signals.

12. The digital distance measuring system of claim 11 wherein said means for generating said remote carrier frequency signal includes a UHF oscillator means for generating a predetermined, fixed, remote carrier frequency signal.

13. The digital distance measuring system of claim 12 wherein said means responsive to said first and second master carrier frequency signals and to said generated fixed remote carrier frequency signal includes:

remote mixer means for sequentially mixing said first and second master carrier frequency signals with said generated remote carrier frequency signal to produce first and second frequency difference signals, respectively; and

remote IF amplifier means responsive to the output of said mixer means for sequentially outputting IF-amplified first and second frequency difference signal.

14. The digital distance measuring system of claim 13 wherein said means for dividing-down said remote carrier frequency signal includes at least one remote digital divide-by-"m" logic circuit.

15. The digital distance measuring system of claim 14 wherein said means for generating said first and second known phase reference signals includes a remote phase comparator means having two inputs and two outputs, one of said inputs being operatively coupled to the output of said at least one remote divide-by-"n" logic circuit means for supplying said divided-down signal thereto, and the other of said inputs being operatively coupled to the output of said remote IF amplifier means for receiving said amplified first and second frequency difference signals therefrom and for outputting said first and second known phase reference signals from one of said outputs.

16. The digital distance measuring system of claim 15 wherein said means for generating said first and second known phase reference signals further includes:

a remote loop filter means having an input operatively coupled to said one output of said remote phase comparator means and an output for supplying said filtered first and second known phase reference signals, said loop filter means forming a phase lock loop including said remote UHF oscillator means, said remote divide-by-"m" logic circuit means, said remote phase comparator means, and a sense-switching means;

an out-of-lock detector means having an input operatively connected to the second output of said remote phase comparator means, and an output for generating a sequence of sense-switching signals whenever said phase lock loop is out-of-lock;

a sense-switching means having two inputs and an output, one of said inputs being operatively connected to the output of said remote loop filter means and the output of said phase sense-switching means being operably connected to said remote UHF oscillator means;

said sense-switching means being adapted to periodically change the polarity of the remote loop filter output for as long as the phase lock loop remains out-of-lock, said means being responsive to a locked state and maintaining polarity of the signal provided to the UHF oscillator means.

17. A method of unambiguously and accurately measuring the distance between the lie of a golfer'"'"'s ball on a golf course and the location of the particular hole toward which the golfer is advancing his golf ball comprising the steps of:

providing a master transceiver system adapted to be positioned proximate the position of the golfer'"'"'s ball;

associating a remote transceiver system with a flag marker at said particular hole for uniquely identifying same;

manually-initiating a request for a measurement of the distance between the golfer'"'"'s ball and said particular hole;

generating a master frequency reference signal;

programming a frequency synthesizer to output a first master carrier frequency signal, using said master frequency reference signal;

modulating said first master carrier frequency signal with a digital data signal and transmitting same to said remote transceiver system;

comparing said digital data signal received by said remote transceiver system with a remotely stored digital data signal indicative of the particular hole'"'"'s unique identification number;

producing an enablement signal in response to a positive identification match;

initiating the generation of a fixed remote carrier frequency signal in response to said enablement signal;

transmitting said remote carrier frequency signal back to said master transceiver system for verifying that said particular hole has been positively identified as the one toward which said golfer is presently advancing his golf ball;

continuing to transmit said first master carrier frequency signal from said master transceiver system to said remote transceiver system;

dividing down the frequency of said remote carrier frequency signal to produce a divided-down remote frequency signal;

mixing said first master carrier frequency signal and said remote carrier frequency signal to generate a first difference frequency signal;

forming a phase lock loop;

inputting said divided down remote carrier frequency signal and said first difference frequency signal to a phase comparator in said phase lock loop and locking said phase lock loop to output a first known phase reference signal indicative of the first distance measurement;

transmitting said remote carrier frequency signal with said first known phase reference back to said master transceiver system;

dividing down said master frequency reference signal to produce a divided-down master signal;

mixing said remote carrier frequency signal having said first known phase reference and said first master carrier frequency signal to generate said first frequency difference signal;

feeding said master divided-down signal and said first frequency difference signal to the input of a master phase detector for outputting said phase detector output signal indicative of a first distance measurement;

converting said first phase detector output signal into an ambiguous distance measurement value because the signal repeats itself every one-half wavelength;

reprogramming said frequency synthesizer to output a second different and distinct master carrier frequency signal for transmission to said remote transceiver system;

again remotely mixing said second master carrier frequency signal and said remote carrier frequency signal to produce a second frequency difference signal;

again feeding said second frequency difference signal and said divided-down remote signal to the inputs of said remote phase comparator means and outputting a second phase detector output signal indicative of the desired distance measurement;

again transmitting said remote carrier frequency signal with said second known phase references data back to said master transceiver system;

again mixing said second master carrier frequency signal and said remote carrier frequency signal having said second known phase reference to reproduce said second frequency difference signal;

inputting said second frequency difference signal and said divided-down master signal to produce a second phase detector output signal;

converting said first and second phase detector output signals into digital distance values, combining same to obtain an unambiguous, highly accurate, distance measurement value; and

displaying said distance measurement value for informing the golfer of the measured distance between the present position of his golf ball and the hole currently being approached.

18. A method for accurately measuring the distance between a point "A" and a remote point "B" comprising the steps of:

positioning a master transceiver at point "A";

locating a remote transceiver at point "B";

generating a first master carrier frequency signal with said master transceiver and transmitting same to said remote transceiver;

generating a fixed remote carrier frequency signal at said remote transceiver;

determining a first frequency difference between said first master carrier frequency signal and said remote carrier frequency signal, where said first master carrier frequency signal is of a lower frequency than said remote carrier frequency signal;

phase-locking said signals to produce a first known phase reference;

transmitting said remote carrier frequency signal with said first known phase reference to said master transceiver;

comparing said first phase-locked remote carrier frequency signal with said first master carrier frequency signal;

regenerating said first known phase difference signal indicative of the measured distance to a particular point on a given waveform cycle;

generating a second master carrier frequency signal and transmitting same to said remote transceiver;

repeating said steps of determining, phase-locking and transmitting said remote carrier frequency signal having a second known phase reference to said master transceiver;

again comparing said phase-locked remote carrier frequency signal having said second known phase reference with said second master carrier frequency signal to generate a second phase difference signal indicative of the measured distance to a particular waveform cycle;

utilizing said generated first and second phase difference signals to compute a digital distance measurement; and

displaying said digital distance measurement for use by the user of the system.

19. A digital distance measuring system for accurately measuring the distance between a point "A" and a remote point "B" comprising:

a master transceiver means locateable at point "A";

a remote transceiver means locateable at point "B";

said master transceiver means including master circuit means for generating a first master carrier frequency signal and transmitting same to said remote transceiver means;

said remote transceiver means including remote circuit means (1) responsive to said first master carrier frequency signal for generating a fixed remote carrier reference signal, (2) for determining the frequency difference between said first master carrier frequency signal and said fixed remote carrier frequency signal, (3) phase-locking said signals and (4) transmitting said phase-locked remote carrier frequency signal with a first known phase reference back to said master transceiver means;

said master circuit means further including means responsive to said first phase-locked remote carrier frequency signal for recreating said first known phase reference indicative of a distant measurement to a point on a given waveform cycle, and then generating a second master carrier frequency signal, and transmitting same back to said remote transceiver means;

said remote transceiver means again (1) determining the phase difference between said first master carrier frequency signal and said remote carrier frequency signal, (2) phase-locking said signals and (3) transmitting said phase-locked remote carrier frequency signal with a second known phase reference back to said master transceiver means;

said master circuit means then again generating a second known phase difference signal indicative of the distance measurement to a given waveform; and

said master circuit means still further including means responsive to said first and second known phase reference signals for computing said measured distance unambiguously and accurately displaying same for distance measurement purposes.

20. A system for accurately measuring the distance between a point "A" and a remote point "B" comprising:

a master transceiver system operably positionable at point "A";

a remote transceiver system operatively positionable at remote point "B";

said master transceiver system including a frequency synthesizer means, a IF amplifier means, and a master circuit means for (1) generating a fixed master reference frequency signal;

(2) first programming said frequency synthesizer means with a desired first master carrier frequency signal and then, a predetermined time later, with a second desired master carrier frequency signal;

said frequency synthesizer means being responsive to said master reference carrier frequency signal and said programming for producing said first master carrier frequency signal and, at a predetermined time later, said second master carrier frequency signal; and

(3) transmitting said first master carrier frequency signal and, at said predetermined time later, said second master carrier frequency signal to said remote transceiver system;

said remote transceiver system including remote circuit means for;

(1) receiving said first and second master carrier frequency signals;

(2) generating a fixed remote reference carrier frequency signal;

(3) mixing said first and second master carrier frequency signals with said remote reference carrier frequency signal for producing first and second frequency difference signals;

(4) IF amplifying said first and second frequency difference signals to produce first and second IF amplified difference frequency signals, respectively;

(5) dividing down said fixed remote reference carrier frequency signal;

(6) comparing the phase of said first and second IF amplified difference frequency signals and said divided down remote reference carrier frequency signal to generate first and second known phase references;

(7) phase-locking said first and second master carrier frequency signals with said remote reference carrier frequency signal, respectively; and

(8) first transmitting said remote carrier frequency signal with said first known phase reference back to said master transceiver means and then, said predetermined time later, transmitting said remote reference carrier frequency signal with said second known phase reference back to said master transceiver system;

said master circuit means of said master transceiver system further including master circuit means for (1) receiving said remote carrier frequency signals;

(2) mixing said remote carrier frequency signal with said first and second master carrier frequency signals, respectively, for generating first and second frequency difference signals, respectively;

(3) dividing down said fixed master reference frequency signal;

(4) IF amplifying said first and second frequency difference signals, respectively;

(5) comparing the phases of said divided down master reference frequency signal with said first and second frequency difference signals to output first and second phase reference distance measurement signals, respectively; and

(6) adding said first and second phase reference signals to calculate a single, unambiguous, highly accurate measurement of the distance between point "A" and point "B".

21. The system of claim 20 wherein said frequency synthesizer means comprises means programmed to produce first and second master carrier frequency signals which are displaced a predetermined distance from said remote carrier frequency signal by an amount equal to the IF frequency for enabling a single, highly accurate, unambiguous distance measurement to be made between points "A" and "B".

22. A method of accurately measuring the distance between a point "A" and a remote point "B" comprising the steps of:

positioning a master transceiver system proximate point "A";

locating a remote transceiver system proximate point "B";

generating a master reference carrier frequency at said master transceiver system;

synthesizing a first master carrier frequency signal where said first master carrier frequency signal equals said master reference carrier frequency signal plus a first IF frequency signal;

transmitting said first master carrier frequency signal to said remote transceiver system;

producing a remote reference carrier signal where said first master carrier frequency signal is displaced above said remote reference carrier frequency signal;

mixing said first master carrier frequency signal and said remote reference carrier frequency signal to obtain a first frequency difference signal;

IF amplifying said first frequency difference signal;

dividing down said remote reference carrier frequency signal;

comparing the phases of said divided down remote carrier frequency signal and said IF amplified first frequency difference signal;

phase-locking said carrier frequency signals together such that the phase of the IF frequency equals the difference in phase between the first master carrier frequency signal and the remote reference carrier frequency signal and becomes a first known phase reference;

transmitting the remote carrier frequency signal with said first known phase reference back to said master transceiver system;

mixing said remote carrier frequency signal and said first master carrier frequency signal to produce a first difference signal equal to the IF frequency of the master transceiver station;

IF amplifying said first difference frequency signal;

dividing down said master reference carrier frequency signal;

comparing the phases of said divided-down master reference carrier frequency signal and the IF amplified first frequency difference signal to output a first distance measurement signal which is ambiguous because it repeats every one-half wavelength of said first master carrier frequency signal;

synthesizing a second master carrier frequency signal where said second master carrier frequency signal equals said master carrier reference signal minus said first IF frequency;

transmitting said second master carrier frequency signal to said remote transceiver system;

mixing said second master carrier frequency signal and said remote reference carrier frequency signal to obtain a second frequency difference signal;

IF amplifying said second frequency difference signal;

dividing down said remote reference carrier frequency signal;

comparing the phases of said divided down remote reference carrier frequency signal and said IF amplified second frequency difference signal;

phase-locking said carrier frequency signals together such that the phase of the IF frequency equals the difference in phase between the second master carrier frequency signal and the remote reference carrier frequency signal;

transmitting said remote carrier frequency signal with said second known phase reference back to said master transceiver system;

again mixing the remote carrier frequency signal with the second master carrier frequency signal to produce a second frequency difference signal equal to the IF frequency;

IF amplifying the second frequency difference signal;

dividing down the master reference carrier frequency signal;

comparing the phases of said divided-down master reference frequency signal and said IF amplified second frequency difference signal to output a second distance measurement signal which is unambiguous over a predetermined range; and

combining said first and second distance measurement signals to compute the actual, unambiguous, and accurately measured distance between point "A" and point "B".