Honeywell G.m.b.h.

Marie A Stoffer

Douglas E Thorpe

John F Dawson

James A Cousens

Thomas A Kodet

Joseph W Bednarski

A device executing intervisibility calculation includes a mechanism executing a radial spoke scan pattern where individual radials are traversed beginning at a threat installation and extending outward along a radial to a distance corresponding to threat range capability. Intervisibility calculation is simplified to allow implementation in a simple, dedicated hardware engine to provide rapid execution time while ensuring accurate intervisibility results. The intervisibility engine includes lookup tables to provide precalculated data and advantageously avoids divide operations whereby the intervisibility calculation may be executed by use of a series of adds, subtracts, and multiplies relative to intervisibility data developed while traversing a given radial. The engine calculates a slope for each data post visited in traversing a radial, and identifies a data post as being visible when its associated slope is greater than a previously encountered greatest magnitude slope. The engine stores in a digital terrain elevation database an intervisibility ground reference value representing a magnitude of vertical clearance between a given data post elevation and a threat detection envelope thereabove. The execution time provided by the intervisibility engine of the present invention is sufficiently fast to allow dynamic, in-flight calculation to aid in intervisibility calculation relative to a just discovered or just moved threat installation. The digital terrain elevation data may be referenced to display or select routes relative to known or detected threat installations.

Device executing intervisibility calculation

An apparatus for reading a first addressable memory and writing into a second addressable memory wherein the first addressable memory is logically arranged in a rectangular matrix and is scanned at an arbitrary angle with respect to the matrix for producing a plurality of scan patterns whose parameters can be altered and controlled by an external source, while the second addressable memory, also arranged in a rectangular matrix, is written into along parallel rows and columns. The apparatus is particularly adapted for use with a digital map display system having an airborne computer for generation the scan parameters.

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Rio Rancho, NM, United States of America

Marie A Stoffer