When a homing head or seeker is mounted on-board a missile, the inertial reference provided by the seeker may be contaminated to some extent by the motion of the missile body. To alleviate this, seekers are sometimes gimballed and use rate or position gyros or they may be momentum-stabilized--the seeker itself providing the inertial reference. However, gyros are both complex and expensive, and momentum-stabilized seekers tend to have large inertias making it difficult to achieve high scan rates. The guidance system described herein allows the establishment of inertial references via information derived from a seeker which need not be isolated from the missile body, the seeker having a range measuring function which, possibly in combination with one or more accelerometers, is used to control pitch, yaw, roll and stabilization of the missile.
The disclosed circuit decouples the aiming of an electronic scanning antenna from the motions of its platform which is assumed to be a moving body. It has two independent tracking channels which determine the direction cosines of the beam along pitch and yaw axes of a referential trihedron that is related to the platform and that has its roll axis colinear with the direction of orientation of the antenna. Each of these channels is decoupled from the motions of the platform by the introduction of a variable that is deduced, by a stabilization circuit, from the gyrometrical measurements of an inertial unit linked to the platform. This device makes it easy for the beam of the antenna to carry out a watch scanning operation or target-tracking operation that is independent of the motions of the platform. Should the electronic scanning antenna form part of a homing unit of the missile, it can easily be complemented by a proportional navigation guidance device.
A method for determining the rates of turn of the missile/target line of sight with a seeker head rigidly mounted on the missile, characterized in that the azimuth and elevation deviation angles (.psi..sub.sm and .THETA..sub.sm) of the target measured with the rigidly mounted seeker head (2) in the missile-fixed coordinate system (s.sub.1, S.sub.2, s.sub.3) are transformed to the azimuth and elevation deviation angles (.psi..sub.v and .THETA..sub.v) of the target based on the coordinate system (v.sub.1, v.sub.2, v.sub.3) of a virtual, gimbal mounted and gyrostabilized seeker head (2v) that tracks the missile/target line of sight (SL) by rotation with the rates of turn (p.sub.v, q.sub.v, r.sub.v) about its three axes (v.sub.1, v.sub.2, v.sub.3).
Blended missile autopilots for a missile employing direct lift and tail controlled autopilots coupled by way of a blending filter. The blended missile autopilots have movable tails aft of the center of gravity of the missile and side force thrusters or movable canards mounted forward of the center of gravity, and that are controlled using the direct lift and tail-controlled autopilots. Lift is generated from the tails and side force is generated by the thrusters or canards, such that the body of the missile maintains zero angle of attack and generates no lift. The present invention thus combines the fast response of a direct lift autopilot with the high acceleration capability of a body lift autopilot, and blends the two using the blending filter to achieve improved performance.
A plurality of magnetic sensors mounted to a missile frame measure magnetic fields from magnets mounted to the movable portion of a seeker mounted in the missile frame. As the angle of attack changes, the field strength measured by each magnetic sensor changes. The magnetic sensors thus produce signals that may be calibrated and processed to determine the angle of attack.
Methods and systems for providing an estimate of effectiveness of a selected weapon against a selected target prior to release of the weapon are described. One described method comprises receiving a position uncertainty for a weapon platform, receiving a position uncertainty for a selected target, and determining an ability of the selected weapon to navigate to the selected target. An estimated effectiveness of the selected weapon is determined utilizing one or more of the weapon platform position uncertainty, the target position uncertainty, the navigation capability of the selected weapon, and a kill radius for the selected weapon.
