In-Vehicle Terminal

An in-vehicle terminal, comprising:

• a measurement unit that measures electric field strengths of radio waves for wireless communication emitted from information terminals located in a vicinity thereof;
• a main terminal identifying unit that identifies a predetermined main terminal among the information terminals;
• a keeping unit that keeps a first electric field strength for another portable information terminal than the identified main terminal measured by the measurement unit;
• and
• a communication unit that establishes wireless communication with the main terminal and receives a second electric field strength for the other information terminal measured by the main terminal, from the main terminal via the wireless communication.

A computer-readable computer program product having a program to be executed by a computer, the program comprising:

• a measuring step of measuring electric field strengths of radio waves for wireless communication emitted from information terminals located in a vicinity thereof;
• a main terminal identifying step of identifying a predetermined main terminal among the information terminals;
• a keeping step of keeping a first electric field strength for another portable information terminal than the identified main terminal measured in the measuring step;
• and
• a communication step of establishing wireless communication with the main terminal and receiving a second electric field strength for the other information terminal measured by the main terminal, from the main terminal via the wireless communication.