Position estimation system, information terminal used for same, and position estimation method

A method performed by an information terminal in a system including a device and a server, the device including a transmitter configured to transmit a wireless signal associated with identification information, the information terminal including a first transceiver, a second transceiver, and a display, the method comprising:

• receiving, by the first transceiver via the server, position information of the device;
• displaying a first mark on a map displayed on the display based on the position information of the device received by the first transceiver, the first mark indicating a position corresponding to the device;
• when movement of either the information terminal or the device enables the second transceiver of the information terminal to receive the wireless signal from the device without communication via the server, measuring signal intensity of the wireless signal received by the second transceiver;
• estimating a relative positional relationship between the information terminal and the device based on the measured signal intensity of the wireless signal;
• and
• displaying a second mark, different from the first mark, corresponding to the device on the display, wherein a form of the second mark is varied according to the signal intensity of the wireless signal received by the second transceiver.