Patent ID: 7924219
Filing Date: 2011-04-12
Classification: G01S

Abstract:
1. A positioning method, comprising: determining a receiving environment of 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 predicted value of the 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 first measurement error for the positioning satellite based on a signal strength of the satellite signal; setting a suitability condition of the observed value based on the receiving environment; setting a second measurement error larger than the first measurement error when the observed value is not suitable by the suitability condition; setting the second measurement error equal to the first measurement error when the observed value is suitable by the suitability condition; correcting the state vector using the observed value and the second measurement error being larger than the first measurement error, when the observed value is not suitable by the suitability condition; and correcting the state vector using the observed value and the second measurement error being equal to the first measurement error, when the observed value is suitable by the suitability condition.