{
  "$type": "site.standard.document",
  "description": "A terrain-referenced navigation system for an aircraft comprises: a stored digital terrain map; a position calculation unit arranged to calculate aircraft position relative to the stored digital terrain map to determine a terrain-referenced aircraft position; a fall line calculation unit arranged…",
  "path": "/patents/1297415",
  "publishedAt": "2021-08-12T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "F41G7/2226",
    "Atlantic Inertial Systems Limited"
  ],
  "textContent": "A terrain-referenced navigation system for an aircraft comprises: a stored digital terrain map; a position calculation unit arranged to calculate aircraft position relative to the stored digital terrain map to determine a terrain-referenced aircraft position; a fall line calculation unit arranged to calculate a fall line for a projectile starting from the terrain-referenced aircraft position as a launch point; and an impact point calculation unit arranged to directly compare the fall line with the digital terrain map, by incrementally comparing a height of the projectile along the fall line with a height of the terrain according to the stored digital terrain map in order to find an expected impact point on the terrain.",
  "title": "PROJECTILE RANGING WITH DIGITAL MAP"
}