Extended range, light weight laser target designator

• US 6,926,227 B1
• Filed: 04/27/1977
• Issued: 08/09/2005
• Est. Priority Date: 04/27/1977
• Status: Expired due to Term

• Current Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Original Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Inventors: Misek, Victor A., Young, Donald S.
• Primary Examiner(s): Gregory, Bernarr E.
• Assistant Examiner(s): Webb, Thomas H.
• Application Number:
  US05/792,958
• Time in Patent Office: 10,331 Days
• Field of Search: 244/3.16, 244/3.13, 244 31- 33, 343/7.7, 343/17.1, 342/27, 342/28, 342 52- 59, 342 61- 67, 342 73- 81, 342147-158, 342/175, 342/195, 89/11.1
• US Class Current: 244/3.13
• CPC Class Codes: F41G 7/226 Semi-active homing systems, i.e. comprising a receiver and involving auxiliary illuminating means, e.g. using auxiliary guiding missiles
• CPC Class Codes: F41G 7/2293 using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 3/783 using amplitude comparison of signals derived from static detectors or detector systems
• CPC Class Codes: G01S 7/486 Receivers

Abstract

Pulse integration is utilized on board an optically guided missile or other ordinance device used as a part of a target designation system for extending the lock-on range of the missile by approximately 18%, when a double pulse laser is utilized to illuminate and designate the target. Pulse integration is accomplished with a recirculating delay unit which superimposes the first pulse on the second pulse, such that while the pulses add coherently, noise does not add in phase. The pulse integration technique therefore enhances the signal-to-noise ratio when the missile is at the outer limits of its operating range. When the missile is sufficiently close to the target, doublet decoding is actuated to offer countermeasure resistance. At this point, pulse integration may proceed in lieu of doublet decoding or may be dispensed with in view of the increased signal-to-noise ratio due to the close range of the missile to the target.

Claims

1. Apparatus for extending the range of a multi-pulse target designation system in which an ordinance device is provided with optical tracking apparatus and a guidance system coupled thereto, said tracking apparatus being adapted to detect the presence and position of pulses returned from an illuminated target, comprising:

means for coherently integrating the pulses detected by said tracking apparatus prior to the utilization of the integrated pulses for the guidance of said ordinance device, and,

means for coupling the integrated pulses to said guidance system.

2. The apparatus of claim 1 wherein said means for coherently integrating the detected pulses includes means for delaying a first pulse by an amount corresponding to the interpulse spacing between the first pulse and a second pulse and means for recombining the delayed pulse with the second pulse.

3. The apparatus of claim 2 wherein said means for delaying includes a delay line and wherein said recombining means includes a summing network having at least one input coupled to the output of said delay line.

4. The apparatus of claim 2 wherein said means for delaying includes a serial analog delay unit.

5. The apparatus of claim 1 and further means for generating a gating signal responsive to the intensity of the pulsed radiation incident on said tracking apparatus exceeding a predetermined threshold, and to the incidence of pulses having a predetermined inter-pulse spacing at said tracking apparatus, and,

means for gating the detected pulses to said guidance system responsive to the generation of said gating signal.

6. The apparatus of claim 5 wherein said gating means transmits to said guidance system pulses from said integrating means.

7. The apparatus of claim 5 wherein said gating means gates to said guidance system unintegrated detected pulses.

8. A method of extending the range of a multi-pulse target designation system in which an ordinance device is provided with optical tracking apparatus which detects the presence and position of pulses returned from an illuminated target comprising:

coherently integrating the pulses detected by the tracker prior to the utilization of the detected pulses for the guidance of said ordinance device.

9. The method of claim 8 wherein the step of coherently integrating the detected pulses includes the steps of delaying a first pulse by an amount corresponding to the inter-pulse spacing between the first pulse and a second pulse and recombining the delayed pulse with the second pulse.

10. The method of claim 8 and further including the steps of generating a gating signal responsive to the intensity of the pulsed radiation incident on the tracking apparatus exceeding a predetermined threshold, and responsive to the incidence of pulses having a predetermined inter-pulse spacing at said tracking apparatus, and,

gating the detected pulses to the guidance system of said ordinance device responsive to the generation of the gating signal.

11. A method of extending the range of a multi-pulse target designation system in which an ordinance device is provided with optical tracking apparatus which detects the presence and position of pulses returned from an illuminated target comprising:

coherently integrating the pulses detected by the tracker when said ordinance device is outside a predetermined adaptive range perimeter centered on said target and,

utilizing the integrated pulses in the guidance of said ordinance device.

12. The method of claim 11 wherein the step of coherently integrating the detected pulses includes the steps of delaying a first pulse by an amount corresponding to the inter-pulse spacing between the first pulse and a second pulse and recombining the delayed pulse with the second pulse.

13. The method of claim 11 and further including the steps of generating a gating signal responsive to the intensity of the pulsed radiation incident on the tracking apparatus exceeding a predetermined threshold which determined a predetermined adaptive range perimeter, and to the incidence of pulses having a predetermined inter-pulse spacing at said tracking apparatus, and,

gating the detected pulses to the guidance system of said ordinance device responsive to the generation of the gating signal.

14. A method of extending the range of a multi-pulse target designation system in which an ordinance device is provided with optical tracking apparatus which detects the presence and position of pulses returned from an illuminated target comprising:

coherently integrating the pulses detected by the tracking apparatus when the pulsed radiation at ordinance device is below a predetermined value.

15. The method of claim 14 wherein the step of coherently integrating the detected pulses includes the steps of delaying a first pulse by an amount corresponding to the expected inter-pulse spacing between the first pulse and a second pulse and recombining the delayed pulse with the second pulse.

16. An extended range target designation system comprising:

laser target designating means which projects at least two pulses of electromagnetic radiation of known inter-pulse spacing towards a target, and,

a guided ordinance device, said device having a guidance system and optical tracking apparatus coupled thereto for detecting the location of pulsed radiation scattered by said target towards said ordinance device, said optical tracking apparatus including means for coherently adding said pulses and for transmitting the resulting signal to said guidance system whereby the operating range of said tracking apparatus is extended.

17. The system of claim 16 wherein said optical tracking apparatus includes means for permitting only pulses having said known inter-pulse spacing to affect the guidance system of said ordinance device when said ordinance device is within a predetermined adaptive range perimeter centered on said target, said range perimeter being dependent on the intensity of the pulsed radiation scattered by said target.