| 摘要 |
A navigation system is provided. An in-vehicle device is mounted on a vehicle. A data providing apparatus provides data regarding navigation to the in-vehicle device. The data providing apparatus detects current position data of the vehicle, accumulates map image data, cuts the map image data in a display size of the in-vehicle device, and separately transmits the detected current position data and the cut map image data to the in-vehicle device. The in-vehicle device receives the current position data and the cut map image data from the data providing apparatus, and superimposes the received current position data and the cut map image data to display a guide image. The current position data is transmitted in a first transmission cycle and the cut map image data is transmitted in a second transmission cycle which is shorter than the first transmission cycle. The current position data is updated while maintaining the cut map image data when the current position data is received, and the cut map image data is updated when the current position data is located at an update position in the periphery of the cut map image data.
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