Multi-spectral seeker antenna
First Claim
1. A multi-spectral seeker system for detecting radiation within a plurality of frequency bands throughout the electromagnetic spectrum, a first band being in the ultraviolet-through-infrared portion and at least two additional bands being in the remaining lower frequency portion of said spectrum, comprising:
- a first dichroic energy collection means, being transparent to radiant energy in said additional bands and having a first boresight axis, for collecting energy in said first band;
first conversion means for converting radiant energy collected in said first band to an electrical signal;
a second dichroic energy collection means, being transparent to radiant energy in all but the first of said additional bands and having a second boresight axis, for collecting energy in said first additional band;
second conversion means for converting radiant energy collected in said first additional band to an electrical signal;
at least one third energy collection means, having a third boresight axis, for collecting energy in the second of said additional bands and for converting that energy to an electrical signal; and
phase compensation means for correcting phase error in said second additional band introduced by said first dichroic energy collection means;
wherein said first and second dichroic energy collection means are located coaxially one behind the other and said at least one third energy collection means are located behind and coaxially with said first and second dichroic energy collection means.
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Accused Products
Abstract
A multi-spectral seeker system for detecting radiation in the infrared (IR) band and a plurality of radio frequency (RF) bands suitable for use in a guided missile is disclosed. The IR and RF seekers are coaxially integrated on a single gimbaled platform and share a common aperture without significant performance degradation. In the preferred embodiment, the IR seeker uses a Cassegrainian reflector assembly with surfaces reflective to IR but transparent to RF signals. The first RF seeker uses a resonant dichroic reflector antenna which is transparent to RF signals at frequencies no closer than 0.5 octaves from the dichroic reflector system operating frequency. The second RF seeker may use any suitable RF antenna system although a planar-array of multi-mode spiral antennas or a standard flat plate slotted array are preferred. The second RF seeker may operate in an active, semi-active, or passive mode. The IR seeker means and both RF seeker means together provide coaxial seeking in a single aperture covering three frequency bands without significant loss of performance in the RF antenna and IR sensor. The material on which the parabolic reflector is formed is tapered in thickness as a function of radius to eliminate phase delays introduced by the curvature as seen by the second RF seeker.
77 Citations
15 Claims
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1. A multi-spectral seeker system for detecting radiation within a plurality of frequency bands throughout the electromagnetic spectrum, a first band being in the ultraviolet-through-infrared portion and at least two additional bands being in the remaining lower frequency portion of said spectrum, comprising:
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a first dichroic energy collection means, being transparent to radiant energy in said additional bands and having a first boresight axis, for collecting energy in said first band; first conversion means for converting radiant energy collected in said first band to an electrical signal; a second dichroic energy collection means, being transparent to radiant energy in all but the first of said additional bands and having a second boresight axis, for collecting energy in said first additional band; second conversion means for converting radiant energy collected in said first additional band to an electrical signal; at least one third energy collection means, having a third boresight axis, for collecting energy in the second of said additional bands and for converting that energy to an electrical signal; and phase compensation means for correcting phase error in said second additional band introduced by said first dichroic energy collection means; wherein said first and second dichroic energy collection means are located coaxially one behind the other and said at least one third energy collection means are located behind and coaxially with said first and second dichroic energy collection means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification