{
  "$type": "site.standard.document",
  "coverImage": {
    "$type": "blob",
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  "description": "A terrain-referenced navigation system (600) for an aircraft comprises: a stored digital terrain map (606); a position calculation unit (608) arranged to calculate aircraft position relative to the stored digital terrain map (606) to determine a terrain-referenced aircraft position; a fall line…",
  "path": "/patents/1419175",
  "publishedAt": "2026-04-01T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "B64D1/04",
    "ATLANTIC INERTIAL SYSTEMS LTD [GB]"
  ],
  "textContent": "A terrain-referenced navigation system (600) for an aircraft comprises: a stored digital terrain map (606); a position calculation unit (608) arranged to calculate aircraft position relative to the stored digital terrain map (606) to determine a terrain-referenced aircraft position; a fall line calculation unit (612) 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 (614) 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 (606) in order to find an expected impact point on the terrain.",
  "title": "PROJECTILE RANGING WITH DIGITAL MAP"
}