Abstract: A communication apparatus communicates with a radio communication device. The communication apparatus includes a display unit, a controller, a first receiver, a second receiver, and a transmission unit. The controller is configured to switch between a first mode and a second mode, the second mode in which the display unit is not supplied power. The first receiver unit is configured to receive a request message from the radio communication device in the second mode. The second receiver unit is configured to receive a measuring information that is related to a position of the communication apparatus in response to the request message received by the first receiver unit. And the transmission unit is configured to transmit position that is calculated based on the measuring information.