RANGE AND TIME MEASURE SYSTEM

• US 3,618,089 A
• Filed: 01/29/1969
• Issued: 11/02/1971
• Est. Priority Date: 01/29/1969
• Status: Expired due to Term

• Current Assignee: Robert B. Moran Jr
• Original Assignee: Robert B. Moran Jr
• Inventors: Moran, Robert B. Jr.
• Primary Examiner(s): Tubbesing, T. H.
• Application Number:
  US04/794,937
• Time in Patent Office: 1,007 Days
• Field of Search: 343/5DP,7.3,13,17.7,15,13R 340/1 324/68C,68CV,186,187
• US Class Current: 368/107
• CPC Class Codes: G01S 13/103 particularities of the measurement of the distance G01S13/12, G01S13/14, G01S13/16, G01S13/18 and G01S13/20 take precedence
• CPC Class Codes: G01S 13/16 using counters
• CPC Class Codes: G01S 13/66 Radar-tracking systems; Analogous systems
• CPC Class Codes: G01S 13/76 wherein pulse-type signals are transmitted
• CPC Class Codes: G01S 2013/466 by Trilateration, i.e. two antennas or two sensors determine separately the distance to a target, whereby with the knowledge of the baseline length, i.e. the distance between the antennas or sensors, the position data of the target is determined

Abstract

A precision range-measuring system combining digital and analog range-measuring techniques, operable on both a manual and automatic basis. The digital portion of the system is utilized to obtain the most significant digits of the range measurement and determines the amount of time delay after initiation of the range-measuring pulse before energization of the analog portion of the system. The analog portion is utilized to obtain the least significant digits of the range measurement. Readout of range information obtained by the system is provided by various means including direct display and a servo-plotting apparatus. Further refinements are incorporated to increase the accuracy of the analog portion of the system.

Claims

1. A system for measuring the time interval between recurrent transmitted pulses and delayed recurrent received pulses comprising in combination, a. digital time delay generator means for producing recurrent output trigger pulses, said digital time delay generator means including means for setting the time delay interval of said recurrent output trigger pulses with respect to the recurrent transmitted pulses in discrete incremental steps;

b. analog time delay measuring means, coupled to said digital time delay generator means, said analog time delay measuring means being responsive to said recurrent output trigger pulses and being adapted for receiving the delayed recurrent received pulses for measuring the time delay interval between said recurrent output trigger pulses and the recurrent received pulses; and

c. means coupled between said analog time delay measuring means and said digital time delay generator means for increasing the time delay interval of said recurrent output trigger pulses by one discrete incremental step when the time delay interval between said recurrent output trigger pulses and the recurrent received pulses reaches a predetermined upper limit and for decreasing the time delay interval of said recurrent output trigger pulses by one discrete incremental step when the time delay interval between said recurrent output trigger pulses and the recurrent received pulses reaches a predetermined lower limit.

2. The system as defined by claim 1 wherein the difference in time between said predetermined upper limit and said predetermined lower limit is substantially equal to one discrete imcremental step of time delay interval of said recurrent output trigger pulses from said digital time delay generator means.

3. The system as defined by claim 1 wherein said digital time delay generator means includes an oscillator producing clock pulses, a first decade counter coupled to said oscillator, and a first switch means coupled to said first decade counter for setting the number of pulses to be counted by said first decade counter.

4. The system as defined by claim 3 wherein said digital time delay generator means further includes a second decade counter coupled to said first decade counter, second switch means coupled to said second decade counter for setting the number of pulses to be counted by said second decade counter, and means coupled to said first and second decade counters for producing said recurrent output trigger pulses.

5. The system as defined by claim 3 wherein each discrete incremental step of time delay interval of said recurrent output trigger pulses is equal to the time interval between successive clock pulses from said oscillator.

6. The system as defined by claim 3 wherein the difference in time between said predetermined upper limit and said predetermined lower limit is substantially equal to the time interval between successive clock pulses from said oscillator.

7. The system as defined by claim 1 further comprising first indicating means coupled to said digital time delay generator means for indicating the time delay interval of said recurrent output trigger pulses in discrete incremental steps.

8. The system as defined by claim 1 further comprising second indicating means coupled to said analog time delay measuring means for indicating the time delay interval between said recurrent output trigGer pulses and the recurrent received pulses.

9. The system as defined by claim 1 wherein said analog time delay measuring means includes a ramp generator means having one input coupled to said digital time delay generator means and a second input adapted to receive the delayed recurrent received pulses, said ramp generator means producing an output voltage having a value proportional to the time delay interval between said recurrent output trigger pulses from said digital time delay generator means and the recurrent received pulses.

10. The system as defined by claim 9 further comprising indicating means coupled to said ramp generator means for indicating the value of said output proportional to the time delay interval between said recurrent output trigger from said digital time delay generator and the recurrent received pulses.

11. The system as defined by claim 9 further including a source of reference voltage, and a servomechanism follow-up loop coupled to said ramp generator means and including a pair of potentiometers connected to the reference voltage source, the pair of potentiometers each having a winding and a movable tap in contact with the winding, the taps being mechanically linked to the servomechanism and spaced a fixed distance apart on their respective winding for producing two servo follow-up voltages, the taps being alternately connectable to the input to the servomechanism and the voltage difference between the movable taps being adjusted to be equal to the voltage difference between a lower and an upper limit value on the ramp voltage in the analog time delay measuring means for measuring said output voltage.

12. A measuring system according to claim 11 further including switching means connected between the follow-up loop and the digital time delay generator means for changing the time delay interval of said recurrent output trigger pulses at the upper and the lower limit values of the ramp voltage and for simultaneously switching the follow-up loop of the servomechanism from one of said potentiometer taps to the other.

13. A measuring system according to claim 12 including digital display means operatively linked to the pair of potentiometers for providing a digital readout of the least significant digits of the range measurement.

14. The system as defined by claim 9 further including, a first sample and hold circuit a second sample and hold circuit, and switching means for alternately connecting the first and second sample and hold circuits to said ramp generator means, the first sample and hold circuit being arranged to sample and hold said output voltage and the second sample and hold circuit being arranged to periodically sample and hold the value of output voltage from said ramp generator means when the value of the output voltage is equivalent to one discrete incremental step of time delay of said recurrent output trigger pulse from said digital time delay generator means.

15. The system as defined by claim 1 wherein said means coupled between said analog time delay measuring means and said digital time delay generator means for increasing or decreasing the time delay interval of said recurrent output trigger pulses includes a range limit detector responsive to an upper limit and to a lower limit of time delay measurement of said analog time delay measuring means.

16. The system as defined by claim 15 wherein the difference in time between said upper limit and said lower limit of time delay measurement is substantially equal to one discrete incremental step of time delay interval of said recurrent output trigger pulses from said digital time delay generator.

17. A system for measuring the time interval between recurrent transmitted pulses and delayed recurrent received pulses comprising in combination, a. digital time delay generator means for producing recurrent output trigger pulses, said digital time delay generator means including means for setting the delay interval of said oUtput trigger pulses with respect to the recurrent transmitted pulses in discrete incremental steps, b. first indicating means coupled to said digital time delay generator means for indicating the time delay interval of said output trigger pulses in discrete incremental steps, c. ramp generator means having one input coupled to said digital time delay generator and a second input adapted to receive the delayed recurrent received pulses, said ramp generator means producing an output voltage having a value proportional to the time delay interval between said recurrent output trigger pulses from said digital time delay generator and the recurrent received pulses, d. second indicating means coupled to said ramp generator means and being responsive to said output voltage for indicating the time delay interval between said recurrent output trigger pulses and the recurrent received pulses, and e. means coupled between said second indicating means and said digital time delay generator means for increasing the time delay interval of said output trigger pulses by one discrete incremental step when the time delay interval between said recurrent output trigger pulses and the recurrent received pulses reaches a predetermined upper limit and for decreasing the time delay interval of said output trigger pulses by one discrete incremental step when the time interval between said recurrent output trigger pulses and the recurrent received pulses reaches a predetermined lower limit.