Object detecting system

• US 4,035,760 A
• Filed: 09/18/1951
• Issued: 07/12/1977
• Est. Priority Date: 09/18/1951
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Richards, James R., Asbury, George F., Kohn, Earl J.
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Berger, Richard
• Application Number:
  US03/247,186
• Time in Patent Office: 9,429 Days
• Field of Search: 343/8, 343/9, 343/13, 343/100, 343/7.7, 177/386.1 ET, 340/3 D
• US Class Current: 367/90
• CPC Class Codes: G01S 13/585 processing the video signal in order to evaluate or display the velocity value
• CPC Class Codes: G01S 15/582 using transmission of interrupted pulse-modulated waves and based upon the Doppler effect resulting from movement of targets

Abstract

1. A system for detecting the movement of a remote object comprising trantting means for illuminating said remote object with a signal of wave energy, receiving means for recovering an echo reflected by said object, signal display means responsive to said echo to provide a separate visual display of each cycle of said reflected echo, and frequency comparing means responsive to a difference in frequency between the wave energy of said received echo and the wave energy of said transmitted signal to vary the orientation of said visual indication from a reference orientation, whereby a variation in said orientation will provide an instantaneous indication of a doppler effect on said transmitted wave energy.

Claims

1. A system for detecting the movement of a remote object comprising transmitting means for illuminating said remote object with a signal of wave energy, receiving means for recovering an echo reflected by said object, signal display means responsive to said echo to provide a separate visual display of each cycle of said reflected echo, and frequency comparing means responsive to a difference in frequency between the wave energy of said received echo and the wave energy of said transmitted signal to vary the orientation of said visual indication from a reference orientation, whereby a variation in said orientation will provide an instantaneous indication of a doppler effect on said transmitted wave energy.

2. A system for detecting the movement of remote objects comprising transmitter means for illuminating an object with a pulse of wave energy, receiver means for recovering a portion of said wave energy pulse reflected by said remote object, a local oscillator for generating local oscillations at the frequency of said transmitted wave energy, display means for producing a separate visual display of each cycle of said pulse from said object, said visual display having an orientation which is responsive to the phase difference between successive cycles of the wave energy of each reflected pulse and successive cycles of said local oscillations whereby objects producing a doppler effect on said transmitted pulse will be displayed with an orientation different than the display of objects producing no doppler effect.

3. A system for measuring the range rate of a remote object comprising transmitter means for illuminating said object with a pulse of wave energy, receiver means for recovering an echo pulse of said wave energy reflected by said object, a local oscillator for generating local oscillations, display means for producing a separate visual display of each cycle of said echo pulse, said visual display having an orientation which is responsive to the phase difference between successive cycles of the wave energy of said echo pulse and successive cycles of said local oscillations, frequency adjusting means in said local oscillator for tuning said local oscillator to the frequency of said transmitted wave energy to establish a reference orientation on said display means whereby a doppler effect produced on said echo pulse by reflection from said remote object will vary the orientation of the display of said echo pulse, and means measuring the adjustment of said frequency adjusting means necessary to restore said received signal display to said reference orientation to determine the amount of said doppler effect.

4. A system for measuring a change in the range rate of a remote object comprising transmitter means for illuminating said object with pulses of wave energy, receiver means for recovering echo pulses of said wave energy reflected by said object, a local oscillator for generating local oscillations at a frequency approximate to the frequency of said transmitted wave energy, display means for producing a separate visual display of each cycle of said echo pulses, said visual display having an orientation which is responsive to the phase difference between successive cycles of the wave energy of each of said echo pulses and successive cycles of said local oscillations whereby echo pulses from one of said objects having a first range rate will be displayed with a first orientation and echo pulses from said one object after a change from said first range rate will be displayed with a second orientation, means for varying the frequency of said local oscillations to restore the orientation of said display from said second orientation to said first orientation, and means for measuring said variation in said local oscillator frequency.

5. In a wave energy echo system for detecting remote objects including means for illuminating a remote object with a wave energy signal and recovering a reflection thereof from said object, means for determining the doppler effect produced on a transmitted wave energy signal by reflection from a remote object comprising a local oscillator, means adjusting said local oscillator to the transmitted wave energy frequency, receiver means for recoverng said reflected signal, display means fed by the output of said local oscillator and the reflected signal for indicating the difference between the period of cycles of the wave energy in said reflected signal and respective cycles in the output of said local oscillator, means varying said local oscillator frequency to reduce the indication of said difference to zero, and means measuring said variation.

6. A system for measuring the range rate of a remote object relative to that of a selected reference object comprising transmitter means for illuminating both of said objects with signal pulses of wave energy, receiver means for recovering wave energy echo pulses reflected from said objects, signal display means for producing a separate visual display of each cycle of said echo pulses, a local oscillator for generating local oscillations, said visual display having an orientation which is responsive to the phase difference between successive cycles of said local oscillations and successive cycles of the wave energy of said respective echo pulses, means adjusting the frequency of said local oscillations to establish a reference orientation of the echo pulses from said selected reference object, means for varying the frequency of said local oscillations by an amount necessary to orient the display of remote object echo signals in said reference orientation, and means for measuring said frequency variation, whereby said frequency variation provides a measure of the difference in range rate between said remote object and said selected reference object.

7. In a wave energy echo system for detecting remote objects by transmitting wave energy signals having a particular frequency and receiving said wave energy signals after reflection from said objects, received signal display means for indicating the detection of an object comprising an untuned receiver for receiving said reflected signals, a cathode ray indicator tube including means producing an electron beam and a luminescent screen receiving said beam, spike generating means operative responsive to a selected rate of change of amplitude in each cycle of the wave energy of said received signals to generate a control signal having a duration short relative to the period of said particular frequency signal, means producing a constant velocity sweep of said electron beam across said luminescent screen in a first direction at an adjustable reference frequency, means producing a constant velocity sweep of said electron beam across said screen in a second, orthogonal direction at low frequency, intensity control means for said electron beam operative responsive to said control signal to produce a bright spot on said luminescent screen, and means for adjusting said reference frequency to equal said particular frequency, whereupon said bright spots representing signals having said particular frequency form coherent traces having a horizontal orientation on said luminescent screen and said bright spots representing signals having frequencies different from said particular frequency form coherent traces having a sloping orientation on said luminescent screen.

8. In a system for detecting objects by transmitting wave energy and recovering a portion of said wave energy reflected by said objects, means for indicating a moving object comprising an oscillograph having a two coordinate indicating medium, an indicating element therefor, first deflection means for cyclically sweeping said indicating element at constant velocity across said medium in a first coordinate, second deflection means for cyclically sweeping said indicating element at constant velocity across said medium in a second coordinate, and control means for actuating said indicating element responsive to a control signal;

means generating said control signal from each cycle of the reflected wave energy to form successive indications on said indicating medium;

means operating said first deflection means at a frequency approximate to that of said transmitted wave energy;

means operating said second deflection means at an adjustable low frequency to form a coherent oscillogram from said successive indications on said indicating medium; and

means for varying the sweep frequency of said first deflection means to define a reference orientation of said oscillogram when the frequency of said reflected wave energy equals that of the transmitted wave, whereby an oscillogram formed from reflected wave energy having a frequency different than said transmitted wave frequency will have an orientation different than said reference.

9. In a system for detecting objects by transmitting wave energy and recovering a portion of said wave energy reflected by said objects, means for indicating a moving object comprising an oscillograph having a two coordinate indicating medium, an indicating element therefor, first deflection means for cyclically sweeping said indicating element at constant velocity across said medium in a first coordinate, second deflection means for cyclically sweeping said indicating element at constant velocity across said medium in a second coordinate, and control means for actuating said indicating element responsive to a control signal;

means generating said control signal from each cycle of the reflected wave energy to form successive indications on said indicating medium;

means operating said first deflection means at a frequency approximate to that of said transmitted wave energy;

means operating said second deflection means at low frequency to form a coherent oscillogram from said successive indications on said indicating medium;

means for varying the sweep frequency of said first deflection means to define a reference orientation of said oscillogram when the frequency of said reflected wave energy equals that of the transmitted wave, whereby an oscillogram formed from reflected wave energy having a frequency different than said transmitted wave frequency will have an orientation different than said reference; and

means for indicating the variation of said first deflection frequency necessary to restore the orientation of said oscillogram to the reference orientation, to provide a measure of the frequency difference between said transmitted and reflected waves.

10. In a wave energy echo system for detecting remote objects including means for illuminating a remote object with a wave energy signal and recovering a reflection thereof from said object, means for displaying said reflected signal comprising an oscillograph having a two coordinate indicating medium, an indicating element therefor, first deflection means for cyclically sweeping said indicating element at constant velocity across said medium in a first coordinate, second deflection means for cyclically sweeping said indicating element at constant velocity across said medium in a second coordinate, and control means for actuating said indicating element responsive to a control signal;

means generating a control signal from each cycle of the wave energy in said reflected signal to form successive indications on said indicating medium;

means operating said second deflection means at a low frequency to form a coherent oscillogram from said successive indications on said indicating medium;

means for controlling the sweep frequency of said first deflection means to define a reference orientation of said oscillogram when the frequency of said reflected wave energy equals a selected frequency, whereby an oscillogram formed from reflected wave energy having a frequency different than said selected frequency will have an orientation different than said reference; and

means for indicating the variation of said first deflection frequency necessary to restore the orientation of said oscillogram to the reference orientation, to provide a measure of the frequency difference between said reflected and said selected frequency.

11. Means for measuring the velocity in a selected direction of a vehicle relative to a reference object comprising means for propagating a train of wave energy having a particular frequency from said vehicle in said selected direction and recovering a reflection of said propagated wave energy from said object;

means for generating a control signal from each cycle of said recovered wave energy;

an oscillograph including a two coordinate indicating medium, an indicating element therefor and control means for actuating said indicating element responsive to said control signals;

first deflection means for cyclically sweeping said indicating element across said medium in a first direction at said particular frequency;

second deflection means for cyclically sweeping said indicating element across said medium in a second direction normal to said first direction at a frequency low relative to said particular frequency to form from the indications of successive control signals on said medium an oscillogram having a reference orientation when said velocity equals zero;

means for varying the first direction sweep frequency of said indicating element from said particular frequency by an amount necessary to orient the oscillogram produced by wave energy reflected from said reference object in said reference orientation; and

means for measuring said sweep frequency variation to indicate the doppler effect on the wave energy in said train.

12. Means for indicating the speed of a first object relative to a second object in a selected direction comprising means for illuminating said first and second objects with a train of wave energy traveling in said selected direction and recovering a reflection of said wave energy from each of said objects;

means for generating a control signal from each cycle of the wave energy in said reflected wave energy signals;

an oscillograph including a two coordinate indicating medium, an indicating element therefor and control means for actuating said indicating element responsive to said control signals;

first deflection means for cyclically sweeping said indicating element across said medium in a first direction at a first frequency;

second deflection means for cyclically sweeping said indicating element across said medium in a second direction normal to said first direction at a frequency low relative to said first frequency to form from said control signals oscillograms on said medium representing said reflected signals;

means for adjusting said first frequency to position said oscillogram representing said reflected signal from said first object in a selected reference orientation on said medium;

means for varying said first frequency from its adjusted value to position said oscillogram representing said reflected signal from said second object in said selected reference orientation; and

means for indicating the amount of said frequency variation.

13. In a wave energy echo system for detecting remote objects including means for illuminating a remote object with a pulse of wave energy having a particular frequency and recovering a reflection thereof from said object, means for displaying the inter-cycle phase modulation and measuring the doppler effect impressed on the wave energy of said pulse by reflection from said object to indicate the phase modulating characteristics of the reflecting surface of said object and the relative velocity of said object comprising an oscillograph including a two coordinate indicating medium, an indicating element therefor and control means for actuating said indicating element responsive to said control signals;

first deflection means for cyclically sweeping said indicating element across said medium in a first direction at said particular frequency;

second deflection means for cyclically sweeping said indicating element across said medium in a second direction normal to said first direction at a frequency low relative to said particular frequency to form from the indications of successive control signals on said medium an oscillogram having a reference orientation when the frequency of said reflected wave energy equals said particular frequency;

means for varying the first direction sweep frequency of said indicating element from said particular frequency to orient the oscillogram produced by wave energy reflected from said remote object in said reference orientation, whereupon the shape of said oscillogram provides a characteristic indication of said inter-cycle phase modulation; and

means for measuring the magnitude of said frequency variation.

14. In a wave energy echo system for detecting remote objects by transmitting wavetrain signals and recovering echoes thereof from said objects, means for obtaining from a single echo the range, range rate and wave energy reflecting characteristics of a remote object comprising means for generating a control signal from each cycle of the wave energy in said echo;

an oscillograph including an indicating medium and an indicating element therefor;

first deflection means for cyclically sweeping said indicating element across said medium in a fist direction at the frequency of the wave energy in said transmitted signal;

second deflection means for sweeping said indicating element across said medium in a second direction normal to said first direction to establish a time base;

means for synchronizing the start of said second direction time base sweep with the transmission of said transmitted signal;

control means for actuating said oscillograph indicating element responsive to each of said control signals to produce an indication on said medium, whereupon the plurality of indications representing the respective control signals produced from the respective cycles of wave energy in said echo form a coherent oscillogram on said indicating medium;

said oscillogram having a particular displacement on said time base in said second direction proportional to said object range, a particular configuration indicative of said object wave energy reflecting characteristics, and being oriented with a slop proportional to said object range rate.

15. In a wave energy echo system for detecting remote objects by transmitting wavetrain signals and recovering echoes thereof from said objects, means for obtaining from a single echo the range, range rate and wave energy reflecting characteristics of a remote object comprising means for generating a control signal from each cycle of the wave energy in said echo;

an oscillograph including an indicating medium and an indicating element therefor;

first deflection means for cyclically sweeping said indicating element across said medium in a first direction at the frequency of the wave energy in said transmitted signal;

second deflection means for sweeping said indicating element across said medium in a second direction normal to said first direction to establish a time base;

means for synchronizing the start of said second direction time base sweep with the transmission of said transmitted signal;

control means for actuating said oscillograph indicating element responsive to each of said control signals to produce an indication on said medium, whereupon the plurality of indications representing the respective control signals produced from the respective cycles of wave energy in said echo form a coherent oscillogram on said indicating medium;

said oscillogram having a particular displacement on said time base in said second direction proportional to said object range, a particular configuration indicative of said object wave energy reflecting characteristics, and being oriented with a slop proportional to said object range rate;

means for adjusting the sweep frequency of said first deflection means to orient oscillograms representing echoes from objects having a selected range rate in a selected reference orientation, whereupon a particular oscillogram representing an echo from a particular object having a different range rate will have an orientation different than said reference orientation;

means for varying the sweep frequency of said first deflection means to restore the orientation of said particular oscillogram to said reference orientation; and

means for measuring said frequency variation to determine the doppler effect produced by said particular object.

16. A system for measuring a change in range rate of a remote wave signal source comprising means for receiving signals generated by said source;

means for generating a control signal from each cycle of the wave energy in said received signals;

an oscillograph including a two coordinate indicating medium, an indicating element therefor and control means for actuating said indicating element responsive to said control signals;

first deflection means for cyclically sweeping said indicating element across said medium in a first direction at a first frequency;

second deflection means for cyclically sweeping said indicating element across said medium in a second direction normal to said first direction at a frequency low relative to said first frequency to form from said control signals oscillograms on said medium representing said received signals;

means for adjusting said first frequency to position said oscillograms representing said received signals in a selected reference orientation on said medium corresponding to a first range rate of said remote signal source;

whereupon a change in the range rate of said remote signal source will produce an instantaneous variation in the orientation of the display of said received signals; and

calibrated means for measuring the adjustment of said frequency adjusting means necessary to restore the orientation of said received signal display to said reference orientation.