PHASE-LOCKED PULSED DISTANCE-MEASURING EQUIPMENT UTILIZING A COARSE SCALE AND FINE SCALE MEASUREMENT

• US 3,614,226 A
• Filed: 03/17/1969
• Issued: 10/19/1971
• Est. Priority Date: 03/17/1969
• Status: Expired due to Term

• Current Assignee: Ronald A. Vergoz
• Original Assignee: Ronald A. Vergoz
• Inventors: Vergoz, Ronald A.
• Primary Examiner(s): Farley, Richard A.
• Assistant Examiner(s): Potenza, J. M.
• Application Number:
  US04/807,667
• Time in Patent Office: 946 Days
• Field of Search: 356/5,4 343/13
• US Class Current: 356/5.08
• CPC Class Codes: G01S 17/14 wherein a voltage or current pulse is initiated and terminated in accordance with the pulse transmission and echo reception respectively, e.g. using counters

Abstract

An electromagnetic distance-measuring device wherein the time of transit of signals to and from a target is measured to determine a coarse scale distance to the target. An additional fine scale measurement of the distance to the target is provided by measuring the phase shift of the returned signal. The reflected energy, when received, triggers a counter to provide the coarse time measurement. The fine scale increment is provided by measuring the phase shift of the returned signal relative to a high-frequency control signal.

Claims

1. A distance-measuring device comprising means for directionally transmitting an interrogating signal, including a series of pulses of electromagnetic energy, toward a target area, means for receiving portions of said interrogating signals reflected by targets within the target area, means coupled to said receiving means for selectively measuring the time of transit of said interrogating signals to and from the target, means coupled to said time-measuring means for displaying the measured time of transit as a coarse scale distance to the target, means coupled to said receiving means and including a sawtooth wave signal generator means responsive to a control signal to generate a sawtooth voltage output at the frequency of said control signal and a sample-and-hold phase comparator one input to which is coupled to the output of said sawtooth wave generator, and responsive to a second input comprised of said received reflected portion of said interrogating signals for determining the phase shift in the reflected portions of said interrogating signals between the time of transmission and the time of reception of said signals, and means coupled to said phase-shift-determining means for displaying said phase shift as a fine scale portion of the distance to the target.

2. The device of claim 1 further including analogue to digital converter means coupled to the output of said sample-and-hold phase comparator to convert the voltage output thereof into a digital output equivalent, and means within the audio frequency range.

3. A pulse delay distance-measuring device, comprising:

means for directionally transmitting interrogating signals comprised of pulses of electromagnetic energy, means for receiving portions of said interrogating signals reflected by a target within a selected range, means coupled to said receiving means for selectively measuring the time of transit of said inteRrogating signals to and from the target, means coupled to said time-measuring means for displaying said time of transit as a coarse scale distance to the target, reference frequency generator means coupled to said transmitting means for supplying a clock-rate control signal to said transmitter means, divide-by-n counter means coupled between said reference frequency generator means and said transmitter means, the value of n being such as to render the pulse rate of said transmitter means within the audio frequency range, phase detector means coupled to said receiving means and said reference frequency generator means and responsive to said control signal and said reflected signals for detecting a phase difference therebetween and for providing an output representative thereof, and means responsive to the output of said phase detector means for displaying a fine scale distance readout to the target.

4. The device of claim 3 further including a storage register responsive to said clock-rate control frequency and said received reflected signals to record the time of transmit of said interrogating signals to and from a target, and wherein said coarse scale distance display means is responsive to an output of said storage register.

5. The device of claim 1 further including zero-set means having one input comprising said control signal, and an output comprising the control signal input to said phase detector means.