Seeker/Sensor Technology Assessment for ECAP

1. Seeker/Sensor Technology Assessmentfor ECAP Presented by Tim Carroll Session 2 - Carroll

2. Seeker/Sensor Technology AssessmsntHuntsville, Alabama January 16, 2004 Tim Carroll AMCOM tjcarroll@knology.net Session 2 - Carroll

3. Seeker/Sensor Technology Assessment Outline • Definitions • Background Information • Seeker Types • Radar Seekers • Electro-Optical Seekers • Laser Seekers Session 2 - Carroll

4. Definition of a Seeker • Definition - The seeker is the eye of a missile. Its job is to acquire and track the target until the missile impacts the target. The seeker provides bore-sight error signals (position of the target relative to the center axis of the missile) to the guidance algorithms. This energy is usually electromagnetic (EM) but can be other forms of energy as well (i.e., acoustic). • Seeker Block Diagram Target To Guidance Computer Electrical Processor Gimbal Platform Receiver/Detector Aperture (Antenna or Optics) Transmitter Session 2 - Carroll

5. Seeker Field-of-View and Field-of-Regard • Field-of-View – The angular area in space at which the seeker can observe at any given time (the FoV for radar seekers if referred to as ‘Beam Width’). • Field-of-Regard – The total angular area that a seeker can view by slewing the seeker aperture up and down and left to right on gimbals. Some missile seekers have no slewing mechanism and are called strap-down seekers (then the FoV and FoR are the equal). Session 2 - Carroll

6. Seeker/Sensor Discipline Interaction Operational Engagement Requirements Engagement Time Lines Coverage Area Aerodynamics Nose Shape Guidance Scheme Seeker Type (Active or Passive) System Simulation FoV Detection Range Size Constraints Diameter Length Seeker/Sensor Design Mechanical Design and Layout Size Weight Target Type Wavelength Power Requirements Cost Constraints Strap-Down vs. Gimballed Multi-Mode Electrical System Power Requirements Voltage Current Logistics Considerations Packaging and Handling Session 2 - Carroll

7. Electromagnetic Waves • An electromagnetic disturbance that is composed of time-varying electric and magnetic fields and can transport energy through space, even if no matter is present in that space, is called an electromagnetic wave (abbreviated EM). • EM waves propagate at the speed of light. • The electric and magnetic waves in an EM wave are oriented at 90 degrees to each other and to the direction of propagation. • EM waves travel in straight lines. • Objects in temperature above absolute zero emit EM waves in the Infrared (IR) spectrum. Direction of Propagation Session 2 - Carroll

8. EM Wavelengths and Frequencies • EM frequencies and wavelengths are related by the following expression: where l = wavelength, c = speed of light (3x108 meters/sec), and f = frequency of oscillation. Session 2 - Carroll

9. EM Atmospheric Attenuation Session 2 - Carroll

10. Classification of Seekers/SensorsSpectral Band • Seekers are catagorized by which spectral band of EM radiation they operate within • Microwave • MMW • E-O (Visual and IR) • Laser (CO2 – 10.6mm, YAG – 1.06mm, GaAs – 0.9mm) Session 2 - Carroll

11. Classification of Seekers/SensorsActive/Passive/Semi-Active • Active seekers transmit energy and the receive the reflected energy. Examples are Microwave Radars, Millimeter Wave Radars, and Laser Radars (LADAR). • Passive seekers look for natural occurring EM radiation (Infrared) or reflected EM radiation (Visual). • Semi-Active Seekers operate in one of two modes: • Other asset illuminates target while missile seeker operates in a passive mode to detect reflect EM radiation. • Missile is guided to target by other asset and then the missile seeker becomes active near the target. This is also called “Terminal Active” Session 2 - Carroll

12. Classification of Seekers/SensorsStabilization Mechanization • Stabilized Seeker Head • Seeker Head is isolated from the missile body motion through gimbals, servo motors, and rate sensors. A clear stabilized image/signal is presented to the seeker detectors. • Increase cost,complexity, size and weight • Strap-Down Seeker • Seeker is rigidly attached to the missile body and observes the same motion as the missile • Cheaper, lower quality image/signal, smaller Field of Regard • Limited engagement geometries Session 2 - Carroll

13. Microwave Radar Seekers/Sensors Advantages • All Weather • Range and Range Rate Information • Long Operating Ranges • Low degradation due to battlefield obsurants • Doppler detection for moving targets • Low drag nose shapes Disadvantages • Large Components • Large Aperature • Active Mode • Large Angular Resolution • High Cost State of the Art • Phased Array Radars • Doppler Beam Sharpening • Synthetic Aperture Radar • Radiometric • Multisensor/Sensor Fusion Microwave Radars are best suited for large missiles or ground based systems Session 2 - Carroll

14. Millimeter Wave Seekers/Sensors Advantages • All Weather with some degradation • Range and Range Rate Information • Small Components • Small Angular Resolution • Doppler detection for moving targets • Low drag nose shapes Disadvantages • Active Mode • High Cost • Relatively Short Operating Ranges State of the Art • Small Components • Doppler Beam Sharpening • Strapdown Configurations • Radiometric • Multisensor/Sensor Fusion MMW Wave Radars are suited well for small missiles and short detection ranges Session 2 - Carroll

15. IR Seekers/Sensors Advantages • Small Components • Small Aperture • Very Small Angular Resolution • Passive Mode • Small Miss Distances • Aim-point Bias Capability Disadvantages • Weather Degradation - Moderate • Battlefield Obscurant Degradation - Moderate • No Range or Range Rate Information • High Cost • High Drag Nose Shapes Required State of the Art • Focal Plane Array • Uncooled IR Sensors • Strapdown Configurations • Multisensor/Sensor Fusion IR Seekers are suited well for small missiles and short detection ranges that require precise hit locations Session 2 - Carroll

16. Visual Seekers/Sensors Advantages • Small Components • Small Aperture • Very Small Angular Resolution • Passive Mode • Small Miss Distances • Aim-point Bias Capability Disadvantages • Weather Degradation - High • Battlefield Obscurant Degradation - High • No Range or Range Rate Information • High Cost • High Drag Nose Shapes Required • Cannot Operate at Night State of the Art • Strapdown Configurations • Multisensor/Sensor Fusion Visual Seekers are not in use much anymore due to the lack of night vision and lack of capability in obscured environments Session 2 - Carroll

17. Laser Seekers/Sensors Advantages • Small Components • Small Aperture • Range and Range Rate Information • Small Miss Distances • Aim-point Bias Capability Disadvantages • Weather Degradation - High • Battlefield Obscurant Degradation - High • Dependency on Designator (Semi-Active) • High Cost • No Fire-and-Forget Capability • Small Search Areas State of the Art • LADAR • Side-Looking Beamriders • Multisensor/Sensor Fusion Laser Seekers are used in semi-active missiles where designating assets are available Session 2 - Carroll

18. Sample Calculations Snapshot from MS Excel utility used in Seeker/Sensor Design. Session 2 - Carroll