To provide a position estimation device of an electronic key system capable of reducing operation loads of position estimation using an array antenna and also simplifying communication area setting of a transmitter for making an electronic key perform a response operation.
In the electronic key system, when the electronic key transmits an ID code signal Sid and a vehicle receives the ID code signal Sid with the array antenna, while the radio arrival direction of the ID code signal Sid is confirmed by a position estimation algorithm, an ID code included in the ID code signal Sid is checked and the propriety of ID checking establishment is confirmed. The position estimation device includes; initial position calculation means for calculating an initial position required for the operation of the position estimation algorithm by confirming the electronic key has returned the ID code signal Sid in response to a request signal Srq transmitted from which transmitter; and key position estimation means for estimating the position of the electronic key using the position estimation algorithm on the basis of the initial position calculated by the initial position calculation means.
IWASHITA AKITOSHI
KIKUMA NOBUYOSHI
NAGOYA INST TECHNOLOGY
Makoto Onda