Navigation apparatus and method
US7945382B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 13, 2008 |
| Grant date | May 17, 2011 |
| Priority date | — |
| Expiry date | Aug 29, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C21/3881
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A navigation apparatus and method increase the upper limit for the number of times map data may be written into a portable storage medium. A CPU reads an initial radius and an additional radius increment from a ROM and repeatedly adds the additional radius increment to the initial radius to obtain, with each addition, a new calculated radius centered on coordinates of a central geographic point of a map data extracting-region. The map data for each secondary grid unit within the map data extracting-region is sequentially read out from a CD-ROM. Then, when the map data within the incrementally enlarged map data extracting-region exceeds the maximum storage capacity of the SD memory card, the CPU deducts the last added increment of radius from the calculated radius to obtain a map region to be stored. The CPU sequentially reads out from the CD-ROM the map data for each grid unit within the map region to be stored and sequentially writes the grid units of map data into the SD memory card.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.