Patent ID: 6327028
Filing Date: 2001-12-04
Classification: B60T,G01S

Abstract:
A night distance judging system for use by an observer viewing a scene comprising:at least two spaced apart marker devices formed on a first object, each marker device providing a signal compatible with a night vision device;a night vision device (NVD) viewing apparatus adapted to detect relative positions of the signals from the markers, and create an image of the relative positions of the markers within a field of view;a reticle formed with the NVD having a reticle spacing between lines suitable to be superimposed on the field of view of the viewing apparatus; and,the reticle spacing being selected to form a control area within which simultaneous appearance of at least two images of the spaced apart markers indicates that the first object is at a distance at least as great as a desired distance from the viewing apparatus; and, simultaneous appearance of less than two images of the spaced apart markers within the control area indicates that the first object is at a distance less than the desired distance from the viewing apparatus; said reticle spacing being calculated by the formula L*SIN(A) where L is a distance between an eyepiece of the NVD to a retina of the operator and SIN(A) equals the result of a distance from the NVD to a plane formed by the spaced apart market devices divided into a distance between at least two of the spaced apart markers; andthe observer during use of the night distance judging system forms a vertex of an isosceles triangle composed of the observer and two of the spaced apart marker devices with the NVD having the reticle being located between the observer and the marker devices.