{
  "$type": "site.standard.document",
  "description": "A navigation system detects a present position of a movable body and performs a navigation for the movable body on the basis of map information. The navigation system is provided with: a storage device (15) of non-volatile type capable of writing the map data thereinto and reading the map data…",
  "path": "/patents/1112048",
  "publishedAt": "2001-06-27T00:00:00.000Z",
  "site": "at://did:plc:oql6ds5vnff4ugar6rruliwd/site.standard.publication/3mn3ohu7oxx5w",
  "tags": [
    "G01C21/3667",
    "PIONEER CORP [JP]"
  ],
  "textContent": "A navigation system detects a present position of a movable body and performs a navigation for the movable body on the basis of map information. The navigation system is provided with: a storage device (15) of non-volatile type capable of writing the map data thereinto and reading the map data therefrom; a map data transferring device (11) for obtaining the map data corresponding to a predetermined area, and transferring and storing the map data corresponding to the predetermined area to the storage device; an empty area judging device (11) for judging whether or not an empty storage area having a predetermined capacity is reserved in the storage device when the map data transferring device is to transfer the map data corresponding to the predetermined area to the storage device; and an erasing device (11) for determining unnecessary data among data stored in the storage device on the basis of a predetermined condition, and erasing the unnecessary data from the storage device if the empty area judging device judges that the empty storage area is not reserved.",
  "title": "Navigation system"
}