COLLISION AVOIDANCE SYSTEM

• US 3,697,987 A
• Filed: 11/12/1970
• Issued: 10/10/1972
• Est. Priority Date: 11/12/1970
• Status: Expired due to Term

• Current Assignee: Sp-Marine Incorporated
• Original Assignee: Richard J. Arthur
• Inventors: Arthur, Richard J.
• Primary Examiner(s): Hubler, Malcolm F.
• Application Number:
  US05/088,783
• Time in Patent Office: 698 Days
• Field of Search: 343/11R,5EM,112CA
• US Class Current: 342/41
• CPC Class Codes: G01S 1/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 13/937 of marine craft

Abstract

A collision warning and collision avoidance radar navigation system employs the tau collision warning criterion to derive an improved presentation on a radar plan position or other cathode ray indicator. An intruding target is labelled dangerous if the ratio of intruder closing range to his range rate is seen to be less than a predetermined value by the observation of the relative position of a synthesized bearing marker generated on the display for each target echo.

Claims

1. Collision avoidance apparatus comprising:

radar means for detecting echoes corresponding to a first object location coordinate value at a first instant of time and to a second object location coordinate value at a second instant of time of a movable object in the vicinity of said collision avoidance apparatus, storage means for storing at said first instant of time a representation of said first coordinate value, read out control means for reading said storage means at said second instant of time and for modifying said first coordinate value by a predetermined factor, and means for the simultaneous display at said second instant of time of first and second images of said object respectively in terms of said second coordinate value and of said modified first coordinate value.

2. Apparatus as described in claim 1 wherein:

said radar receiver means comprises means for detecting echoes corresponding to range and bearing coordinate values of said movable object each at respective first and second instants of time, and said storage means comprises means for storing at said first instant of time of a representation of said range and bearing coordinate values at said first instant of time.

3. Apparatus as described in claim 2 wherein said read out control means comprises means for modifying and reading out said value of said stored range value and for reading out said stored bearing value.

4. Apparatus as described in Claim 3 wherein said means for simultaneous display comprises means for displaying said first and second images respectively in terms of said bearing value and of said modified range value at said first instant of time and in terms of said bearing and range values at said second instant of time.

5. Apparatus as described in claim 1 comprising means for modulation alteration of said image representing said modified first coordinate value.

6. Apparatus as described in claim 4 comprising means for modulating said bearing value of said first instant of time for the purpose of causing said first image to have a distinctive demarcation with respect to said second image.

7. Apparatus as described in claim 6 wherein said distinctive demarcation takes the form of an arc of a circle.

8. In a radar system having a cathode ray beam indicator means wherein an object echo signal is represented by forming an image on the screen of said indicator means in terms of the range and bearing coordinates of said object and wherein said radar system includes radar system range synchronizer means providing synchronizing signals for synchronizing the start of the range sweep for sweeping said cathode ray beam relative to said indicator screen in range and antenna bearing pick off means for synchronizing the start of sweeping of said cathode ray beam relative to said indicator screen in bearing, means for intensifying said cathode ray beam comprising:

storage means comprising;

electron beam projection means, target means having electron storage capability, and electrode means for intensifying an electron beam from said electron beam projection means, means under control of said antenna bearing pick off means for applying said echo to said electrode means for intensifying said electron beam of said storage means during a first scan of said antenna, first deflection control means for supplying a substantially constant amplitude range sweep field in a region between said projection means and said target means for positioning said intensified electron beam according to object range during said first scan of said antenna relative to said target means, second deflection control means cooperating with said antenna bearing pick off means for supplying a substantially constant amplitude saw tooth bearing sweep field in said region, means under control of said antenna bearing pick off means for read out of said target means during scans of said antenna subsequent to said first scan, means cooperating with said first deflection means for supplying during said subsequent scans, cycles of an increasing amplitude saw tooth range sweep field in said region, and means for conveying an output of said read out means for intensifying said cathode ray beam of said cathode ray indicator.

9. Apparatus as in claim 8 wherein said first deflection means comprises:

integrator means having first and second input means and output means, said first input means being supplied with a substantially constant electrical signal, said second input means being supplied with integrator reset pulses under control of said radar synchronizer means, and said output means being supplied for forming said range sweep field of said storage means.

10. Apparatus as described in claim 8 wherein said means for supplying said increasing amplitude saw tooth range sweep field comprises:

first integrator means having first and second input means and output means, said first input means being supplied with a substantially constant electrical signal, and said second input means being supplied with integrator reset pulses under control of said antenna bearing pick off means, second integrator means having first input means coupled to said first integrator output means, second and third input means, and output means, said second input means being supplied with a substantially constant electrical signal, said third input means being supplied with integrator reset pulses under control of said radar synchronizer means, and said output means being supplied for forming said increasing amplitude range sweep field of said storage means.

11. Apparatus as described in claim 8 comprising:

first and second storage means comprising;

first and second respective electron beam projection means, first and second respective target means having electron storage capability, and first and second respective electrode means for intensifying first or second respective electron beams from said respective first and second electron beam projection means, means under control of said antenna bearing pick off means for applying said echo to said first electrode means for intensifying said electron beam of said first storage means during a first time interval and for applying said echo to said second electrode means for intensifying said electron beam of said second storage means during a second time interval, first deflection control means for supplying a substantially constant amplitude range sweep field in a first region between said first projection means and said first target means for positioning said first intensified electron beam according to object range during said first time interval relative to said first target means and for supplying a substantially constant amplitude range sweep field in a second region between said second projection means and said second target means for positioning said second intensified electron beam according to object range during said second time interval relative to said second target means, second deflection control means cooperating with said antenna bearing pick off means for supplying a substantially constant amplitude saw tooth bearing sweep field in said first and second regions, means under control of said antenna bearing pick off means for read out of said second target means during said first time interval and for read out of said first target means during said second time interval, means, cooperating with said first deflection means for the supplying, during said second period of time, of cycles of an increasing saw tooth range sweep field to said first region and for supplying, during said first period of time, oF cycles of an increasing saw tooth range sweep field to said second region. means, under control of said antenna bearing pick-off means, for alternately conveying outputs of said first and said second read out means for intensifying said cathode ray beam of said cathode ray indicator.

12. Apparatus as described in claim 11 comprising means under control of said antenna bearing pick off means for modulating said antenna bearing pick off field applied to said first storage means during read out of said first storage means and for similarly modulating said antenna bearing pick off field applied to said second storage means during read out of said second storage means for demarcation purposes.

13. Collision avoidance apparatus comprising:

radar means for detecting an echo corresponding to the range Ro at a first instant of time and at the range at a second instant of time of a movable object in the vicinity of said collision avoidance apparatus, storage means for storing a representation of said range Ro at said first instant of time, read out control means for reading out and modifying said stored representation of range Ro by a factor (1- lambda t) for the generation at said second instant of time of a representation of apparent range Ra substantially defined by the equation;

Ra (1- lambda t)Ro where t is the elapsed time between said first and second instants of time and lambda is a manually selectable constant, and means for display of first and second images of said object, said first image representing said object at said range at said second instant of time, and said second image representing said object at said apparent range Ra.

14. Apparatus as described in claim 13 comprising means for modulation alteration of the form of said second image representing said object at said apparent range Ra so that it is readily distinguished from said first image representing said object at said range at said second instant of time.

15. Apparatus as described in claim 14 wherein said means for altering the form of said second image representing said object at said apparent range Ra comprises means for generation on said means for display of an arc of a circle bisected by the unmodulated portion of said second image.