Abstract: A terrain correlation system for use in conjunction with an inertial navigation system of a vehicle is provided which can update position information and which is both independent of altitude and compatible with varying course paths. In the preferred embodiment, reference terrain altitude maps are converted to reference map transformation values. The reference map transformation values are used in conjunction with a terrain correlation process to establish vehicle position. The system also is able to select reference map scenes to the left, right, front or rear of present vehicle position so that curved travel paths can be updated in a manner similar to more conventional straight line vehicle paths.

Abstract: An apparatus for measuring the height and cross-track offset of a surface location from a moving platform is defined. First and second antennas positioned on an underside of the platform are directed downwardly toward the surface. A transmitter associated with one of the antennas transmits a signal toward the surface. A first coherent detector associated with the first antenna detects a received signal corresponding to the transmitted signal as reflected by the surface and generates in-phase and quadrature components of the detected signal relative to the transmitted signal. A second coherent detector associated with the second antenna detects a received signal corresponding to the transmitted signal as reflected by the surface and generates a second set of in-phase and quadrature components of the detected signal relative to the transmitted signal. An analog to digital (A/D) converter converts the in-phase and quadrature components into digital information stored in a memory.

Abstract: Stable measurement of terrain-height variations is provided by this radar system which employs a very low power spread spectrum transmitted signal which, after reception, is processed digitally for extremely stable and predictable performance. The system also includes an automatic power control circuit to maintain the transmitted power at the minimum required level.

Abstract: A clutter discriminating fuze apparatus for preventing prefires and duds which may result through the use of electronic countermeasure techniques by the enemy.