Laser source location system

An avionics device for locating a source of a laser beam emanating from a source position and aimed at an aircraft, comprising:

• (a) a laser sensor that detects a direction from which the laser beam is sourced relative to a known point on the aircraft and that generates a laser angle signal representative thereof;
• (b) a position sensor that generates a position signal indicative of the aircraft's position in three dimensions relative to a coordinate system of a predetermined frame of reference;
• and
• (c) an attitude sensor that generates an attitude signal indicative of the aircraft's pitch, bank and yaw relative to the predetermined coordinate system;
• and
• (d) a processor that is responsive to the laser sensor, the position sensor and the attitude sensor, that determines a source direction of the laser beam relative to the known point based on current values of the laser angle signal, the position signal and the attitude signal;
• wherein the laser sensor comprises a pixelated sensor that is sensitive to the laser beam;
• a mask, disposed between the source of a laser beam and the pixelated sensor, the mask including an opaque portion that is opaque to the laser beam and a window portion that is at least translucent to the laser beam so that when the laser impinges upon the mask an image of the window portion is projected onto the pixelated sensor;
• and the processor that determines an angle of incidence of the laser beam with respect to the mask by determining a number of pixels that the image of the window is offset from where the image of the window would be if the laser beam had been normal to the mask.

A system for detecting a direction of a source of a laser beam, comprising:

• (a) a pixelated sensor that is sensitive to the laser beam;
• (b) a mask, disposed between the source of a laser beam and the pixelated sensor, the mask including an opaque portion that is opaque to the laser beam and a window portion that is at least translucent to the laser beam so that when the laser impinges upon the mask an image of the window portion is projected onto the pixelated sensor, the window portion having a shape that includes at least a first edge and a second edge that is transverse to the first edge;
• and
• (c) a processor that determines an angle of incidence of the laser beam with respect to the mask by determining a number of pixels that the image of the window is offset from where the image of the window would be if the laser beam had been normal to the mask,
• wherein the angle of incidence along a first axis (α1) is calculated based on a distance (A1) from the first edge to the pixelated sensor and a distance (B1) between an image of the first edge projected by the laser beam onto the pixelated sensor and where the image of the first edge would have been had the laser beam been normal to the mask, according to the following formula:
• α
• 1
• =
• tan
• -
• 1
• ⁡
• (
• A
• 1
• B
• 1
• )
• and wherein the angle of incidence along a second axis (α2) is calculated based on a distance (A2) from the second edge to the pixelated sensor and a distance (B2) between an image of the second edge projected by the laser beam onto the pixelated sensor and where the image of the second edge would have been had the laser beam been normal to the mask, according to the following formula:
• α
• 2
• =
• tan
• -
• 1
• ⁡
• (
• A
• 2
• B
• 2
• )
• where the second axis is perpendicular to the first axis.