Seiko Epson Corporation

Koichiro Yano

Shunichi Mizuochi

Yoshiyuki Muraguchi

Hidekazu Maezawa

A positioning method includes: executing a first positioning mode or a second positioning mode, a first positioning process that is performed using a least-square method based on a positioning signal and a second positioning process that is performed using a Kalman filter based on the positioning signal utilizing a positioning result obtained by the first positioning process as a base value being performed in the first positioning mode, and the second positioning process being further performed in the second positioning mode utilizing a positioning result obtained by the second positioning process as a base value; determining accuracy of a positioning result obtained by the second positioning process performed in the executed positioning mode; and changing the positioning mode to be executed to the first positioning mode or the second positioning mode corresponding to the accuracy.

Positioning method, positioning device, and program

A positioning method includes: capturing a satellite signal from a positioning satellite; predicting a state vector including a position of a positioning device and a velocity of the positioning device based on the satellite signal; predicting a first distance-equivalent value indicating a distance between the positioning satellite and the positioning device; measuring a second distance-equivalent value indicating a distance between the positioning satellite and the positioning device; calculating an observed value indicating a difference between the first distance-equivalent value and the second distance-equivalent value; setting a measurement error for the positioning satellite based on a signal strength of the satellite signal; changing the measurement error based on a capture data indicating a data of capturing of the satellite signal; and correcting the state vector using the observed value, and the changed measurement error.

Positioning method, program, positioning device, and electronic apparatus

A terminal device receives satellite signals from a plurality of satellite positioning system (SPS) satellites and locates a position. The terminal device periodically calculates a first drift dfof a local oscillator using a reference frequency Hr, calculates a search range of the satellite signal using the first drift df, calculates a second drift dfof the local oscillator using a reception frequency of the satellite signal, calculates a reference frequency error &#x3b2; which is an error of the reference frequency by calculating a difference between the first drift dfand the second drift df, and calculates an error correction value &#x3b2;av of the reference frequency by subjecting a plurality of the reference frequency errors &#x3b2; to a statistical process.

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Nagano, Japan

Koichiro Yano