Matsushita Electric Industrial Co., Ltd.

Hisashi Kurokawa

Tsuyoshi Okada

Masayuki Hamada

Junji Hamada, Legal Representative

Masayuki Hamada, Deceased

To cancel an error in GPS wave propagation time and calculate a relative position of a car running nearby to the own car position with good accuracy, a relative car positioning system using car communication includes a car communication transceiver, a GPS receiving device, a GPS information transmission/reception device, and a relative positioning device. A relative position is determined by determining a GPS wave propagation time difference from a GPS satellite, a wave of which is received by the car running nearby and the own car in common. The difference between the data of GPS wave propagation time at the car running nearby and the data of GPS wave propagation time at the own car is calculated, and if the number of differences of the GPS wave propagation time is obtained by more than three pieces, a relative position of the car running nearby is calculated by solving simultaneous equations expression the relative position as an unknown quantity.

Relative car positioning system using car communication

A relative distance and relative velocity to a target object is accurately estimated even if an error in slopes of the triangular wave modulation, that is unbalanced upward and downward slopes, or error in absolute values in an FMCW radar exists. A first distance estimator estimates a distance up to the target object based on a sum of a beat wave frequency generated between the upward and downward slopes of the triangular wave and an absolute value of an average frequency modulation factor which is a mean value of frequency modulation factors for the upward and downward slopes of the triangular wave, and a first velocity estimator estimates a relative velocity to the target object based on a time difference of the calculated distance. A tentative frequency modulation factor estimator estimates an absolute value of a tentative frequency modulation factor based on the calculated distance and velocity, and then estimates a more accurate relative velocity to the target object based on the estimated absolute value of the tentative frequency modulation factor and the distance calculated by the first distance estimator.

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Kanagawa, Japan

Hisashi Kurokawa