Position determination device, position determination method, and vehicular electronic key system

A position determination device including at least one processor, wherein

• the at least one processor is used in connection with at least one first communication device configured to transmit a signal in a first frequency band, and at least one second communication device configured to communicate with a vehicle mobile device carried by a user of the vehicle using radio waves in a second frequency band different from the first frequency band,
• the at least one processor is configured to cause the position determination device to:
• acquire first data indicating a reception state at the vehicle mobile device of a signal transmitted by the first communication device;
• acquire second data indicating a distance from the second communication device to the vehicle mobile device, the second data being determined by causing the second communication device to communicate with the vehicle mobile device;
• determine a location of the vehicle mobile device based on the first data and the second data;
• acquire, as the second data, data indicating a round trip time, which is a time from transmitting a response request signal to the vehicle mobile device to receiving a response signal from the vehicle mobile device;
• acquire, as the second data, data indicating a transmission and reception phase difference for each of frequencies obtained by transmitting and receiving continuous wave signals at the frequencies in the second frequency band;
• acquire a phase difference measured distance value indicating a distance from the second communication device to the vehicle mobile device based on the transmission and reception phase difference for each frequency;
• and
• determine that the vehicle mobile device is not present in a predetermined target area when the round trip time is equal to or greater than a predetermined value, or when the phase difference measured distance value is equal to or greater than a predetermined value and the round trip time is less than the predetermined value;
• and
• perform a position determination process of the vehicle mobile device using the first data when the round trip time is less than the predetermined value and the phase difference measured distance value is less than the predetermined value.

A position determination method performed by at least one processor used in connection with a plurality of first communication device configured to transmit a signal in a first frequency band and at least one second communication device configured to communicate with a vehicle mobile device and a mobile terminal carried by a user of the vehicle using radio waves in a second frequency band different from the first frequency band, wherein

• determination data is a data set associating, for each of the plurality of first communication devices, the first data and the second data that can be observed when the vehicle mobile device is present within a predetermined target area,
• the at least one second communication device is configured to communicate with a mobile terminal which is a general-purpose information processing terminal in addition to the vehicle mobile device,
• the position determination method comprising:
• acquiring first data from the vehicle mobile device indicating a reception state at the vehicle mobile device of a signal transmitted by the first communication device;
• acquiring second data indicating a distance from the second communication device to the vehicle mobile device, the second data being determined by causing the second communication device to communicate with the vehicle mobile device;
• determining a location of the vehicle mobile device based on the first data and the second data;
• determine whether the vehicle mobile device is located within the target area by comparing actually observed first data and the second data with the determination data;
• acquire a signal indicating a device type from a communication partner in cooperation with the second communication device;
• determine whether a device type of the communication partner corresponds to the vehicle mobile device based on the signal acquired from the communication partner;
• and
• change an algorithm for determining a position of a communication partner depending on whether the device type of the communication partner is the vehicle mobile device.

A position determination method performed by at least one processor used in connection with at least one first communication device configured to transmit a signal in a first frequency band and at least one second communication device configured to communicate with a vehicle mobile device carried by a user of the vehicle using radio waves in a second frequency band different from the first frequency band, the position determination method comprising:

• acquiring first data from the vehicle mobile device indicating a reception state at the vehicle mobile device of a signal transmitted by the first communication device;
• acquiring second data indicating a distance from the second communication device to the vehicle mobile device, the second data being determined by causing the second communication device to communicate with the vehicle mobile device;
• determining a location of the vehicle mobile device based on the first data and the second data;
• acquiring, as the second data, data indicating a round trip time, which is a time from transmitting a response request signal to the vehicle mobile device to receiving a response signal from the vehicle mobile device;
• acquiring, as the second data, data indicating a transmission and reception phase difference for each of frequencies obtained by transmitting and receiving continuous wave signals at the frequencies in the second frequency band;
• acquiring a phase difference measured distance value indicating a distance from the second communication device to the vehicle mobile device based on the transmission and reception phase difference for each frequency;
• and
• determining that the vehicle mobile device is not present in a predetermined target area when the round trip time is equal to or greater than a predetermined value, or when the phase difference measured distance value is equal to or greater than a predetermined value and the round trip time is less than the predetermined value;
• and
• performing a position determination process of the vehicle mobile device using the first data when the round trip time is less than the predetermined value and the phase difference measured distance value is less than the predetermined value.

A vehicular electronic key system comprising:

• a position determination device including at least one processor used in connection with at least one first communication device configured to transmit a signal in a first frequency band and at least one second communication device configured to perform wireless communication using radio waves in a second frequency band different from the first frequency band;
• a vehicle mobile device, which is a dedicated device for a user to operate a vehicle, configured to receive a signal transmitted from the first communication device and perform the wireless communication using the second frequency band;
• and
• a mobile terminal, which is a general-purpose information processing terminal, configured to perform the wireless communication using the second frequency band, wherein
• the vehicle mobile device is configured to:
• activate based on receiving a signal in the first frequency band, and then initiate a wireless communication connection with the position determination device using the radio waves in the second frequency band;
• transmit data indicating a reception strength of a signal in the first frequency band by the wireless communication using the second frequency band;
• transmit a code indicating that a device type is the vehicle mobile device based on establishment of a communication connection with the position determination device;
• and
• transmit and receive a signal for distance measurement with the second communication device when a communication connection with the position determination device has been established,
• the mobile terminal is configured to:
• perform processing related to a communication connection with the position determination device using the radio waves in the second frequency band;
• transmit and receive a signal for distance measurement with the second communication device when a communication connection with the position determination device has been established;
• and
• transmit a code indicating that a device type is not the vehicle mobile device based on establishment of a communication connection with the position determination device,
• the position determination device is configured to:
• acquire second data indicating a distance from the second communication device to a communication partner, the second data being determined by causing the second communication device to carry out a predetermined distance measurement communication;
• acquire a signal indicating the device type from the communication partner using the second communication device;
• determine whether the device type of the communication partner corresponds to the vehicle mobile device based on the signal acquired from the communication partner;
• acquire first data from the vehicle mobile device as the communication partner, the first data indicating a reception status of the vehicle mobile device with respect to a signal transmitted from the first communication device when the device type of the communication partner is the vehicle mobile device;
• and
• determine a location of the vehicle mobile device based on the first data and the second data when the device type of the communication partner is the vehicle mobile device.