Communication device, communication method, communication system, electronic watch, and program

A communication method including:

• measuring time;
• determining whether a communicator is able to receive location information and time information from a server;
• in response to determining that the communicator is able to receive the location information and the time information from the server:
• controlling the communicator to receive the location information and the time information from the server;
• creating first offset information of the measured time and the time information received by the communicator;
• acquiring, from map information that is information associating locations and time differences stored in a memory, a time difference corresponding to a location presented by the location information received by the communicator;
• creating first updated time information based on the measured time, the first offset information, and the time difference corresponding to the location presented by the location information received by the communicator;
• and
• controlling the communicator to transmit the first updated time information to another communication device;
• and
• in response to determining that the communicator is not able to receive the location information and the time information from the server:
• controlling a satellite radio waves receiver to receive radio waves from a satellite;
• creating second offset information of the measured time and time information created based on the radio waves received by the satellite radio waves receiver;
• acquiring from the map information a time difference corresponding to a location obtained based on the radio waves received by the satellite radio waves receiver;
• creating second updated time information based on the measured time, second offset information, and time difference corresponding to the location obtained based on the radio waves received by the satellite radio waves receiver;
• and
• controlling the communicator to transmit the second updated time information to the another communication device.

A non-transitory computer-readable recording medium storing a program for causing a computer to at least perform:

• measuring time;
• determining whether a communicator is able to receive location information and time information from a server;
• in response to determining that the communicator is able to receive the location information and the time information from the server:
• controlling the communicator to receive the location information and the time information from the server;
• creating first offset information of the measured time and the time information received by the communicator;
• acquiring, from map information that is information associating locations and time differences stored in a memory, a time difference corresponding to a location presented by the location information received by the communicator;
• creating first updated time information based on the measured time, the first offset information, and the time difference corresponding to the location presented by the location information received by the communicator;
• and
• controlling the communicator to transmit the first updated time information to another communication device;
• and
• in response to determining that the communicator is not able to receive the location information and the time information from the server:
• controlling a satellite radio waves receiver to receive radio waves from a satellite;
• creating second offset information of the measured time and time information created based on the radio waves received by the satellite radio waves receiver;
• acquiring from the map information a time difference corresponding to a location obtained based on the radio waves received by the satellite radio waves receiver;
• creating second updated time information based on the measured time, second offset information, and time difference corresponding to the location obtained based on the radio waves received by the satellite radio waves receiver;
• and
• controlling the communicator to transmit the second updated time information to the another communication device.

A first communication device comprising:

• a first processor configured to measure time and perform control operations;
• and
• a receiver configured to receive, from a second communication device, first updated time information and a second updated time information, wherein the second communication device comprises a communicator and a second processor configured to:
• measure time;
• determine whether the communicator is able to receive location information and time information from a server;
• in response to determining that the communicator is able to receive the location information and the time information from the server:
• control the communicator to receive the location information and the time information from the server;
• create first offset information of the measured time and the time information received by the communicator;
• acquire, from map information that is information associating locations and time differences stored in a memory, a time difference corresponding to a location presented by the location information received by the communicator;
• create first updated time information based on the measured time, the first offset information, and the time difference corresponding to the location presented by the location information received by the communicator;
• and
• control the communicator to transmit the first updated time information to the first communication device;
• and
• in response to determining that the communicator is not able to receive the location information and the time information from the server:
• control a satellite radio waves receiver to receive radio waves from a satellite;
• create second offset information of the measured time and time information created based on the radio waves received by the satellite radio waves receiver;
• acquire from the map information a time difference corresponding to a location obtained based on the radio waves received by the satellite radio waves receiver;
• create second updated time information based on the measured time, second offset information, and time difference corresponding to the location obtained based on the radio waves received by the satellite radio waves receiver;
• and
• control the communicator to transmit the second updated time information to the first communication device,
• wherein the first processor is configured to change the time measured by the first processor based on the first updated time information received or the second updated time information received by the receiver.