Abstract: An estimator for determining the distance of a moving vehicle to a stationary position includes the determination of actual and estimated velocities of the vehicle along a selected path. An up-dated distance estimate is established by multiplying estimated distance by the ratio of the actual velocity to the estimated velocity. The up-dated estimate is then utilized as the estimated and another up-dated distance is obtained. Iterations continue until the ratio approaches unity indicating that the estimated distance is approximately equal to the actual distance.

Abstract: A viscous damper for absorbing vibrations of low amplitude over a wide frequency range. Two working volumes of resiliently deformable material, in the form of a bellows, are provided in a folded structure joined by a base carrying a restrictive annular fluid passage. Compressive forces applied to the primary volume are transmitted by a damping fluid through the restrictive annulus to the secondary volume, the resulting energy dissipation providing a damping effect. A hermetically sealed configuration provides multi-axis damping and isolation without wearing of frictional surfaces. Large damping values are attained with linear performance over a large dynamic range.

Abstract: An aircraft navigation system is disclosed for use in missions involving unfamiliar terrain and/or terrain having hostile forces. The navigation system includes an inertial navigation system, a map of the terrain with elevational information stored in a digitized format as function of location, a typical energy managed or narrow (radar or laser) beam altimeter, a display system, and a central processing unit for processing data according to preselected programs. The data processing system includes an operational mode (software program) for relating the continuing sequence of altimeter readings with the changing aircraft position on the digitized map. In this manner, the true position of the aircraft can be determined with respect to the digitized map and can be displayed on a plan view of the map. When the correct position of the aircraft with respect to the digitized map is known, a display of the map and the aircraft can provide presentations useful to the navigation of the aircraft, e.g.