Hit verification technique

• US 5,406,290 A
• Filed: 05/02/1994
• Issued: 04/11/1995
• Est. Priority Date: 05/02/1994
• Status: Expired due to Term

• Current Assignee: Mcdonnell Douglas Corporation (The Boeing Co.)
• Original Assignee: Mcdonnell Douglas Corporation (The Boeing Co.)
• Inventors: Blackmon, James B. Jr., James, Jesse C.
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US08/236,337
• Time in Patent Office: 344 Days
• Field of Search: 342/119, 342/125, 342/133, 342/146, 342/176, 342/68, 342/138
• US Class Current: 342/119
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/66 Radar-tracking systems; Analogous systems
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 2013/0272 Multifunction radar
• CPC Class Codes: G01S 7/024 using polarisation effects in waveguides H01P1/165; for aerials H01Q, e.g. H01Q15/22, H01Q15/24, H01Q19/195
• CPC Class Codes: G01S 7/064 using a display memory for image processing G01S7/298 takes precedence
• CPC Class Codes: G01S 7/412 based on a comparison between measured values and known or stored values
• CPC Class Codes: G01S 7/417 involving the use of neural networks

Abstract

An interceptor'"'"'s point of impact on a targeted missile is quickly revealed in the milliseconds preceeding and following the impact by illuminating the target with radar signals at a high pulse repetition rate and observing the reflected radar echoes on an A-scope display. The position within the returned radar echo of a double echo and related changing phenomenon indicates the point of impact. Failing intercept, the miss distance is computed from the relative slant ranges to the targeted missile, the interceptor, and the double echo. The type warhead killed is revealed by a spectrograph slaved to the radar'"'"'s antenna. Various techniques assist with the interpretation of the displayed patterns, including subtraction of previously stored patterns and display of the difference, display of characteristic patterns of various known missiles and interceptors stored in "look up" tables, and neural networks.

Claims

1. Apparatus for assessing the effectiveness of an interception of a targeted incoming missile by a launched intercepting anti-missile, comprising:

a dual mode radar system for detecting and tracking moving craft, said radar system having a tracking mode and an intercept mode for transmitting RF pulses at a high pulse repetition frequency during said intercept mode and a lesser pulse repetition frequency during said tracking mode;

said radar system further including;

antenna means for radiating said radar pulses into space, whereby said radar pulses may be incident upon one or more craft moving through such space;

broad band receiver means for receiving radar echo pulses reflected from any such moving craft, said broad band receiver means having a band width at least as large as the bandwith of said RF pulses being transmitted during said intercept mode;

controller means, said controller means including;

range determining means, responsive to radar echo pulses received by said receiver, for determining the distance between the site of said radar transmitter and each craft detected; and

collision prediction means, responsive to radar echo pulses received by said receiver, for determining the intercraft distance between any two such craft that are simultaneously detected and whether said intercraft distance is decreasing; and

mode switching means for switching said transmitting means from said tracking mode into said intercept mode, responsive to said collision predicting means detecting an inter craft distance of less than a predetermined minimum distance;

display means, coupled to said receiver means and said controller means, for displaying a sequence of A-scope presentation traces of the amplitude of radar echo signals reflected from two crafts while in close proximity and closing upon one another to a collision there between or avoidance of collision, during the period in which said transmitting means is in said intercept mode, to provide a trace representative of the length of at least one of said craft representing the targeted incoming missile and whereby an amplitude variation occuring in such trace represents the location on craft at which collision occured.

2. The invention as defined in claim 1, wherein said controller means further includes:

memory means for temporarily recording a predetermined plurality of said A-Scope presentation traces in sequence to provide a temporary database of said traces, said memory means serially sequencing said traces into memory on a first in first out basis wherein the number of said traces in memory does not exceed said predetermined plurality in number;

computer means and program algorithm means associated with said digital processor means for processing the last A-scope display trace entered within said temporary database in accordance with said program algorithm means to produce a processed display trace and for supplying said processed display trace to said display means for display, whereby any amplitude variation in the last received trace is enhanced for greater visual effect.

3. The invention as defined in claim 2, wherein said algorithm means includes:

means for selecting the most recent trace from said database as a minuend;

means for selecting another of said traces from said database as a subtrahend;

subtraction means for subtracting said subtrahend trace from said minuend trace to produce a difference trace;

and means for supplying said difference trace to said display means for displaying said difference trace.

4. The invention as as defined in claim 3, wherein said means for selecting another of said traces from said database as a subtrahend comprises:

means for selecting the next most recent trace from said temporary database.

5. The invention as defined in claim 2, wherein said algorithm means includes:

means for selecting the last trace from said database as a minuend;

means for determining the mathematical mean of the remaining traces in said databases and selecting said mathematical mean as a subtrahend;

subtraction means for subtracting said subtrahend trace from said minuend trace to produce a difference trace;

and means for supplying said difference trace to said A-scope display for displaying said difference trace.

6. The invention as defined in claim 2, wherein said display means comprises a plurality of A-scope displays.

7. The invention as defined in claim 2, wherein said display means comprises an A-scope display.

8. The invention as defined in claim 2, wherein said computer means includes:

means for determining the mathematical mean of a selected number of the most recent previous patterns stored in memory;

subtraction means for subtracting from the last recorded pattern either the previous pattern or the mathematical mean of a selected number of previous patterns to produce a subtracted pattern, and means for outputting said subtracted pattern for display on said display means, whereby said subtracted pattern is displayed either as an additional trace on an A-Scope that also displays said most recent pattern or on another A-Scope display separate from the one displaying said most recent pattern.

9. The invention as defined in claim 2, wherein said computer means further includes:

means for interpreting the processed traces to determine the occurance of a collision between such craft and the location on such craft of such collision.

10. The invention as defined in claim 9, wherein said means for interpreting the processed traces includes:

neural network program means for determining the distance along one of said two craft where a collision occurs.

11. The invention as defined in claim 1, wherein said transmitter means emits radar RF pulses at a pulse repetition rate of between 10,000 to 40,000 pulses per second and with a pulse width on the order of ten microseconds, and having a bandwidth of between 100 MHz and 400 MHz.

12. The invention as defined in claim 1, wherein said receiver means is of a band width no less than three times as great as the bandwidth of said radar pulses.

13. The invention as defined in claim 1, further comprising:

telescope means, said telescope means being linked to said antenna means for viewing the space being tracked by said radar system; and

spectroscope means coupled to said telescope means, said spectroscope means being programmed to determine the presence of specified emission lines in the ultraviolet and visible spectrum.

14. The invention as defined in claim 13, further comprising:

recorder means for recording the spectral lines detected by said spectroscope means; and

means for activating said recorder means responsive to said radar system being in said intercept mode.

15. The invention as defined in claim 13, wherein said spectroscope means further comprises:

a spectroscope;

means to gate the spectroscope to the operating condition, responsive to said transmitter means being in said intercept mode, to receive a spectrum of light energy generated by a conflagration;

means for displaying and recording the received spectra;

library data base means containing a catalogue of spectral lines and the munitions materials characterized by said spectral lines; and

means for comparing said recorded spectrum with spectral lines in said library to determine the existence of any matches; and

means for displaying the list of munitions materials in said library whose spectral characteristics match those spectral characteristics of the received spectrum.

16. The invention as defined in claim 1, further comprising:

reflection enhancing means carried by at least one of said craft to enhance reflection of incident RF pulses from said radar tranmitter means.

17. The invention as defined in claim 16, wherein said reflection enhancing means further comprises:

a semi-circular torus, said semicircle having a cross section approximately equal to five wavelengths at the frequency of said radar signals, said torus being located adjacent to the front end of the missile coaxial with and surrounding the interceptor body.

18. The invention as defined in claim 16, wherein said reflection enhancing means further comprises:

a series of collars, said collars being spaced along the axis of said interceptor and collaring said interceptor,

each said collar having a triangle shaped cross section, each said triangle having an apex angle, the apex angle of one said triangle being substantially different from the corresponding angle of the remaining collars to thereby increase the chance that at least one of said side panels of said collars is oriented substantially perpendicular to the surface of said target missile.

19. Apparatus for assessing the effectiveness of an interception of a targeted incoming missile by a launched intercepting anti-missile, comprising:

a dual mode radar system for detecting and tracking moving craft, said radar system having a tracking mode and an intercept mode for transmitting RF pulses at a high pulse repetition frequency during said intercept mode and a lesser pulse repetition frequency during said tracking mode;

said radar system further including;

antenna means for radiating said radar pulses into space, whereby said radar pulses may be incident upon one or more craft moving through such space;

broad band receiver means for receiving radar echo pulses reflected from any such moving craft, said broad band receiver means having a band width at least as large as the bandwith of said RF pulses being transmitted during said intercept mode;

controller means, said controller means including;

range determining means, responsive to radar echo pulses received by said receiver, for determining the distance between the site of said radar transmitter and each craft detected; and

collision prediction means, responsive to radar echo pulses received by said receiver, for determining the intercraft distance between any two such craft that are simultaneously detected and whether said intercraft distance is decreasing;

mode switching means for switching said transmitting means from said tracking mode into said intercept mode, responsive to said collision predicting means detecting an inter craft distance of less than a predetermined minimum distance; and

memory means for receiving in sequence a predetermined plurality of successive frames of information, each frame of information being descriptive of the amplitude of radar echo signals reflected from two crafts while in close proximity to and closing upon one another through to collision there between or avoidance of collision, during the period in which said transmitting means is in said intercept mode, to thereby provide a temporary database, said memory means serially sequencing said frames into memory on a first in first out basis wherein the number of said traces in memory does not exceed said predetermined plurality in number;

neural network means to determined from said frames of information in said temporary database the location on one of said craft at which a collision occured between said craft; and

display means for displaying the information determined by said neural network means.

20. Apparatus for assessing the effectiveness of an interception of a targeted incoming missile by a launched intercepting anti-missile, comprising in a mode switching radar system:

an A-scope display for presenting a display of the amplitude variation as against range of a radar echo, said radar echo comprising a composite of a radar echo reflected from an anti-missile missile and another radar echo reflected from an incoming missile targeted for destruction by said anti-missile missile, with said anti-missile missile and said incoming missile closing upon one another, wherein said respective radar echoes overlap in time at said mode switching radar system.

21. The invention as defined in claim 20, wherein said mode switching radar system emits radar pulses at a pulse repetition rate of between 10,000 to 40,000 pulses per second and that have a pulse width on the order of ten microseconds and are of a bandwidth of between 100 MHz and 400 MHz.

22. The invention as defined in claim 20, further comprising:

telescope means and spectrograph means coupled to said telescope means for determining the spectral lines of light received at said radar system emitted from said anti-missile missile and said targeted missile as a consequence of a collision therebetween.

23. The method of assessing the effectiveness of an interceptor'"'"'s interception of a targeted incoming missile, which includes the steps of:

illuminating the interceptor and the target missile with broadband radar pulses at a high pulse repetition frequency, wherein a double radar echo is returned in response;

receiving and processing the reflected radar echoes;

displaying the reflected radar echoes on an A-scope, whereby the amplitude of the returned signal as a function of time is displayed, for providing an indication of the length of the target and the position therealong of the interceptor approaching the target; and

determining from said displayed reflected signal the position along the length of said target missile at which a double reflection, if any, occured.

24. The method as defined in claim 23, wherein the step of determining, includes:

comparing each A-Scope pattern of the most recent radar echo with like A-scope patterns of radar echoes previously received; and

identifying the position of any rapid changes in the amplitude of the displayed pattern.

25. The method defined in claim 23, further including the step of:

monitoring the interceptor and target missile for spectral emissions of known munitions materials.

26. The method defined in claim 25 wherein the step of monitoring, includes:

viewing said interceptor and target missile for spectral emissions as would occur in a conflagration resulting from the collision between said interceptor and target missile;

comparing the received spectral emissions with a plurality of spectral emission characteristics of known munitions materials;

displaying a list of munitions materials whose spectral emissions match those of the received spectral lines.

27. The method as defined in claim 25, wherein the step of monitoring includes:

selecting those high intensity spectral emission lines appearing in the flash of conflagration;

comparing said selected spectral emission lines against a library of information on spectral emission lines that are characteristic of known materials; and

selecting the identity of the materials whose spectral emissions match those appearing in said flash of conflagration; and

outputting information of the identity of the materials selected.