Co-boresighted dual-mode SAL/IR seeker including a SAL spreader
First Claim
1. A dual-mode SAL/IR seeker, comprising:
- an IR detector configured to detect two-dimensional images of focused incident IR energy to generate at least one IR guidance signal;
a positionally-sensitive SAL detector having a system transfer function that converts the spatial displacement of a spot of focused laser energy to a target bearing to generate at least one SAL guidance signal;
a primary mirror having a common aperture for collecting and focusing laser energy and IR energy along a common optical path;
a secondary mirror/lens in the common optical path that creates a central obscuration of the common aperture, said secondary mirror/lens having an aft side facing the primary mirror and a forward side, wherein the aft side is a secondary mirror configured to permit propagation of laser energy there through to the forward side along a first optical path to the SAL detector and to reflect IR energy along a second optical path to the IR detector, said primary and secondary mirrors configured to focus the IR energy to form the two-dimensional images at the detector,wherein the forward side of the secondary mirror/lens is a lens element, said lens element configured and said SAL detector positioned to form a spot of focused laser energy on the SAL detector; and
a spreader positioned in the first optical path between the secondary mirror and the SAL detector away from the aperture stop at the primary mirror and not in the second optical path between the secondary mirror and the IR detector, said spreader configured to spatially homogenize the laser energy to increase the size of the spot of focused laser energy on the SAL detector to set the system transfer function.
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Abstract
In a co-boresighted SAL/IR seeker, the optical system and particularly the secondary lens and position of the SAL detector are configured to produce a well-corrected spot of laser energy at the SAL detector. A spreader is positioned between the secondary mirror/lens and the SAL detector, possibly on the secondary mirror, away from the aperture stop and not in the optical path to the IR detector. The spreader is configured to spatially homogenize the laser energy to increase the size of the spot of focused laser energy at the SAL detector to set the system transfer function to meet slope requirements. Spatial homogenization serves to reduce both boresight shift and slope non-linearities. This approach greatly simplifies the time and labor intensive calibration of the SAL detector'"'"'s system transfer function.
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Citations
17 Claims
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1. A dual-mode SAL/IR seeker, comprising:
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an IR detector configured to detect two-dimensional images of focused incident IR energy to generate at least one IR guidance signal; a positionally-sensitive SAL detector having a system transfer function that converts the spatial displacement of a spot of focused laser energy to a target bearing to generate at least one SAL guidance signal; a primary mirror having a common aperture for collecting and focusing laser energy and IR energy along a common optical path; a secondary mirror/lens in the common optical path that creates a central obscuration of the common aperture, said secondary mirror/lens having an aft side facing the primary mirror and a forward side, wherein the aft side is a secondary mirror configured to permit propagation of laser energy there through to the forward side along a first optical path to the SAL detector and to reflect IR energy along a second optical path to the IR detector, said primary and secondary mirrors configured to focus the IR energy to form the two-dimensional images at the detector, wherein the forward side of the secondary mirror/lens is a lens element, said lens element configured and said SAL detector positioned to form a spot of focused laser energy on the SAL detector; and a spreader positioned in the first optical path between the secondary mirror and the SAL detector away from the aperture stop at the primary mirror and not in the second optical path between the secondary mirror and the IR detector, said spreader configured to spatially homogenize the laser energy to increase the size of the spot of focused laser energy on the SAL detector to set the system transfer function. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A guided projectile, comprising:
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a cylindrically-shaped projectile body; one or more control surfaces on the body; a dome that is mounted on one end of the body, said dome transmissive of laser energy and IR energy; a two-axis gimbal; a dual-mode SAL/IR seeker mounted on the two-axis gimbal inside the body, comprising, an IR detector configured to detect two-dimensional images of focused incident IR energy to generate at least one IR guidance signal; a positionally-sensitive SAL detector having a system transfer function that converts the spatial displacement of a spot of focused laser energy to a target bearing to generate at least one SAL guidance signal; a primary mirror having a common aperture for collecting and focusing laser energy and IR energy propagated through the dome along a common optical path; a secondary mirror/lens between the dome and primary mirror in the common optical path that creates a central obscuration of the common aperture, said secondary mirror/lens having an aft side facing the primary mirror and a forward side, wherein the aft side is a secondary mirror configured to permit propagation of laser energy there through to the forward side along a first optical path to the SAL detector and to reflect IR energy along a second optical path to the IR detector, said primary and secondary mirrors configured to focus the IR energy to form the two-dimensional images at the detector, wherein the forward side of the secondary mirror/lens is a secondary lens element, said secondary lens element configured and said SAL detector positioned to form a spot of focused laser energy on the SAL detector; and a spreader positioned in the first optical path between the secondary mirror and the SAL detector away from the aperture stop at the primary mirror and not in the second optical path between the secondary mirror and the IR detector, said spreader configured to spatially homogenize the laser energy to increase the size of the spot of focused laser energy on the SAL detector to set the system transfer function; and a flight control system that receives the at least one IR guidance signal and the at least one SAL guidance signal and applies a single calibration offset for all X, Y positions to said SAL guidance signal to generate control signals to manipulate the one or more control surfaces to control the flight of the airborne platform. - View Dependent Claims (16, 17)
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Specification