Aisin Seiki Kabushiki Kaisha

Yoshihisa Suwa

Takeshi Ito

Tomio Yasuda

Seiji Ishikawa

Tomohiro Yamamoto

A positioning system is disclosed in which a rate of change .DELTA..DELTA.f in a Doppler shift .DELTA.f of the radio wave transmitted from a GPS satellite is detected in order to determine whether or not an extraordinary radio wave as caused by a multi-path or the like is being received, and a GPS satellite from which an extraordinary radio wave is received is excluded from a group of GPS satellites which are utilized in a positioning calculation. A difference .DELTA.f between a signal frequency f0 transmitted from a GPS satellite and a signal frequency fR receiver is calculated, and a rate of change .DELTA..DELTA.f in the difference .DELTA.f is also calculated. The position of a receiver is calculated on the basis of information transmitted from a plurality of GPS satellites for which the rate of change .DELTA..DELTA.f is equal to or less than a first threshold value, or .DELTA..DELTA.f.ltoreq.30 Hz/s, and the azimuth of a traveling direction of the receiver is calculated on the basis of information transmitted from a plurality of GPS satellites for which the rate of change .DELTA..DELTA.f is equal to or less than a second smaller threshold value or .DELTA..DELTA.f.ltoreq.15 Hz/s.

Positioning system utilizing GPS satellites

A mobile object positioning system includes a GPS signal receiver for receiving positioning radio signals from a plurality of satellites, calculating a present location of a mobile object in accordance with the positioning radio signal and outputting present location data at each of a plurality of calculating times. An electronic controller is provided for updating the present location data at each calculating time, storing the present location data, estimating an error of the present location data in accordance with the positioning radio signals and outputting error data at each estimating time. A vehicle velocity sensor is disposed on the mobile object for detecting the velocity of the moving mobile object and outputting a mobile velocity signal. The electronic controller determines a stationary condition of the mobile object in accordance with the mobile velocity signal and prohibits updating the present location data when a stationary condition of the mobile object is determined and a value of the error data at a present estimating time is larger than that at a last previous estimating time.

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Nishio, Japan

Yoshihisa Suwa