Distance estimation device and distance estimation system

A distance estimation device estimating a distance from a mobile terminal to a vehicle, the distance estimation device comprising:

• the mobile terminal;
• and
• an in-vehicle device provided in the vehicle, wherein
• the mobile terminal includes:
• a terminal transmitter configured to transmit a radio wave to the vehicle;
• and
• a terminal controller configured to control the terminal transmitter,
• the in-vehicle device includes:
• a direction determination unit provided in the vehicle, including a receiver configured to receive the radio wave from the mobile terminal, the receiver being arranged on a side of the vehicle associated with a direction from which the radio wave transmitted by the mobile terminal comes, the direction determination unit being configured to determine the direction from which the radio wave transmitted by the mobile terminal comes based on a strength of a reception signal received by the receiver from the mobile terminal;
• a distance measurement unit configured to receive the radio wave from the mobile terminal and measure a distance from an installation position of the distance measurement unit to the mobile terminal based on an arrival time of the received radio wave from the mobile terminal;
• and
• a correction unit configured to correct the distance measured by the distance measurement unit,
• the direction determination unit is configured to determine the direction whether the radio wave comes from a right, a left, a rear or a front of the vehicle, and
• the correction unit is configured to correct the measured distance to be a distance from an edge of the vehicle to the mobile terminal using a distance in the direction determined by the direction determination unit from the edge of the vehicle to the installation position.