US Government As Represented by the Secretary of the Army

Walter E Miller, Jr

Robert R Mitchell

Jimmy R Duke

Robert L Sitton

Michael M Jones

James W McKelvy

William C Pittman

Michael R Christian

Donald E Lovelace

Gene H Widenhofer

Richard W Currie

Richard G Westrich

Irvin E Dent

Anthony D Blackmon

George W Starkey

Dorwin L Kilbourn

Nicholas J Mangus, Jr

Walter F Fountain

The retro-encoded guidance system guides a flying object in its flight tod its destination by measuring and correcting the angular displacement of its actual trajectory from the straight line-of-sight to the destination. A beam of infrared light emanating from a beacon on the flying object is received and angularly encoded by retro-encoder located at the launcher prior to being returned to the missile. The incident beam and returned beam travel on optical paths that are parallel to each other but opposite in direction. The angular encoding is achieved by a reticle of the retro-encoder imparting frequency modulation to the incident beam, the degree and phase of the modulation depending on the location on the reticle on which the beam is incident.

Retro-encoded missile guidance system

The present invention is an initial guidance system for a missile that has o other guidance or inadequate terminal homing guidance to lock onto a target at the time of missile launch. A laser beam projected from the missile launch station is aimed toward the target. Light from the beam is reflected in random directions (scattered) from aerosol particles that are ever present in the atmosphere. This scattered light strikes light detectors that are located on the sides of the missile. When the missile flies off the direction of the target, the amplitudes of impacting light on these detectors are different on different sides of the missile. Guidance controls activated by these amplitude differences cause the missile to veer toward the center of the beam and thus fly in a direction that is more toward the target.

Scatter-rider guidance system for terminal homing seekers

Van Atta array is used to receive a millimeter wave beam from a beam transmitter located in a missile in flight and retransmit the beam back to its source along its original optical path after the beam is phase conjugated and modulated at a tracking station by imparting to it missile guidance information. The missile extracts guidance information from the retransmitted beam and guides its trajectory closer to the course leading to the target.

Covert millimeter wave beam projector

An optically transparent cylinder having a hemispherical cavity at one end hereof and containing at least one light source and one light detector inside the hemispherical cavity utilizes the prismatic effect of the cylinder to locate an object in space. The light source and detector are located on a disk whose insertion depth into the cavity and tilt angle inside the cavity can be varied to control the sharpness, width and direction of the conical beam output from the cylinder, the beam searching the space for the location of the desired object.

Device and method for monitoring the presence of an object in space

An open loop seeker aiming guiding system for directing a guided missile m its launching to its impact with a target. The system includes a fire control mechanism for initially controlling the flight of missile toward the target. Located on the missile itself is a seeker homing system for homing the missile onto the target signature. The system includes transition means for transferring control of the missile flight from the ground base fire control to the homing guidance control on the missile itself whenever the signal from the fire control is interrupted, the missile has been in flight a predetermined time, or the homing device on the missile itself locks in on the target to an extent predetermined, by comparing the image it receives from the target to an image stored in a storing device on the missile itself. Whenever either of these conditions occur control of the missile is transferred from fire control to the homing device on the missile. Significantly, the seeker is blindly pointed approximately at the target, using information derived from the line of sight guidance during the early portion of the flight. This approximate pointing in flight is what enables seeker target acquisition autonomously later in flight with no area target search required.

Open loop seeker aiming guiding system

A linear detector array is positioned a fixed distance behind a narrow slot n an opaque mask. The array is oriented perpendicular to the slot as viewed from the 'front', or direction of laser energy arrival. Light from the laser source, limited by the mask and slot, falls on only a few adjacent elements of the detector array, depending on the direction of arrival of the light. Further, since such crossed linear elements (slots and array) provide this measure of angle of arrival in the single direction perpendicular to the slot, two such systems of mask, detector linear array, and processing electronics may be employed (one rotated 90 degrees with respect to the other) to provide `vertical` and `horizontal` measurements of direction to the laser source.

Coordinate position detector

In accordance with this invention, a missile referenced beamrider guidance ink is provided in which a continuous wave or pulsed laser output is formed into a gaussian cross section or similarly shaped beam and projected to one offset sensor, or to two sensors located on opposite sides and as far from the missile's roll axis as possible. The rolling missile motion amplitude modulates the received signal and the amplitude of the modulation is a measure of the missile's distance from beam axis. The phase of the modulation provides the direction to beam center.

Missile referenced beamrider

A method and apparatus for projecting a laser beam for communication or guidance purposes wherein transmitted energy goes directly to a receiver area without requiring services of slewing or tracking devices. The energy is precisely directed from a laser transmitter on a missile toward a receiver at a tracking area. By directing the laser energy from a source on the missile during flight and by performing phase conjugating amplification of this laser energy at a tracking area station, atmospheric distortions are removed from the return energy and beam broadening is limited only to the negligible effects of diffraction broadening of the return energy, with the laser return beam being directed almost exclusively back to the missile.

Covert beam projector

The method achieves a top soft armor attack with the favorable attack ang In addition it eliminates the wiping motion. This is accomplished by a small upward exhausting thruster over the warhead. This thruster, activated on command from the launch station, institutes a rapid pitch down rotation of the missile imparting an angular momentum. This angular momentum produces a jet wiping effect in the opposite direction of that produced by the missile forward flight.

Rotating warhead

An optical rangefinder having a transmitter and receiver located closely acent for short range operation allows optimum detection of a target when either or both the target and the rangefinder are moving. An optical window region is established where the transmitter look axis intersects the receiver look axis and is adjustable for providing an output signal when the rangefinder and target are less than approximately ten feet apart. The transmitter may emit either noncoherent or coherent infrared energy. The receiver includes zero crossing detection when a received maximum signal intensity is reached and adequate signal detection means which activates when the signal level exceeds a desired minimum. An output signal is generated when the outputs of these two detection circuits are coincident.

Short range optical rangefinder

The discriminator consists of two major parts; a nonlinear filter for low vel rejection, and inhibiting logic for high level rejection, of ac magnetic fields. The nonlinear filter approximately halves the frequency characteristics of a particular class of signals, while at the same time doubling the frequency of normal interfering signals. The inhibiting logic uses the known in-phase relationship to sense and reject even very large time dependent interference. However, spatially variant signals observed from near field relative motion of two orthogonal magnetic sensors with respect to a ferro-magnetic object have a near quadrature relationship that permits signal recognition even when of less amplitude than the interference.

Power line field interference rejection for magnetic sensors

An open loop reduction in gunner aiming error is provided by a rate gyro dback to the missile command electronics. The low frequency movements are filtered out of the feedback circuit; permitting tracking of low frequency crossing targets, while eliminating higher frequency gunner jitter inputs.

Quasi-stabilization for line of sight guided missiles

The optical beam scanner employs novel utilization of the well known Stark effect. By means of an external applied voltage, a change in the index of refraction of an optical medium is produced. This produces a bending effect on light transmitted through the medium. Varying the applied voltage can be used to vary the refractive index, or a refractive index gradient may be produced by providing a gradient in the applied field, to produce no moving parts scanning of the optical beam.

Optical beam scanner

An improved automatic missile tracking and guidance system wherein a laund missile is guided along a line-of-sight maintained by the operator with the target. The position of an infrared source disposed on the missile is detected and guidance signals generated in accordance therewith to control the flight of the missile along the line-of-sight. The infrared source or beacon disposed on the missile comprises an array of semiconductor light emitting diodes. The solid state characteristics of the light emitting diodes provide heretofore unobtainable reliability over existing beacons. The beacon may be used to produce a modulated, high frequency, rectangular waveform, incoherent emission offering performance improvements including virtual immunity to optical countermeasures.

Light emitting diode beacons for command guidance missile track links

An optical tracking link in an automatic command to line-of-sight missile idance system improves the system efficiency and employs a reuseable light source. In tracking a missile during trajectory toward a target, short pulses of collimated light are transmitted from the launch site toward the missle. These light pulses are received by a missile optical receiver for guidance of the missile and are simultaneously reflected by a retrodirective prism on the missile. The reflected energy follows a path parallel to the incident wave and is thus directed back to the launch site. A missile tracker at the launch site responds to the reflective energy, measuring any deviation of the missile from a line-of-sight axis maintained between the launch site and a target. Guidance commands are transmitted toward the missile for maintaining the missile on the line-of-sight trajectory and containing correctional signals in response to any missile deviation. During intervals between return reflections, the missile tracker can be gated off. This greatly reduces background and jamming source reflections and signals, received by the tracker providing effective counter measures hardening of the system.

Growing community of inventors

Huntsville, AL, United States of America

Walter E Miller, Jr