Patent ID: 7586440

Claim:
A point positioning apparatus which estimates distances between a receiver and satellites and a position of the receiver by utilizing satellite signals transmitted from the satellites, comprising: a satellite data observing device which observes orbit data of the satellites and clock errors of the satellites from a navigation message included in the satellites signals or estimated values by off-line processing; an ionosphere data getting device which gets delay data of an ionosphere; a troposphere data getting device which gets delay data of troposphere; and a position estimating device which: linear-approximates the position of the receiver by using the estimation results of previous positions of the receiver and the orbit data of the satellites, sets up explanatory variables, as unknown values, that include the linear-approximated position of the receiver, an integer ambiguity, a clock error of the receiver, clock errors of the satellites, delays of the ionosphere, delays of the troposphere, sets up objective variables, as observational values, that include carrier phases, code pseudoranges, clock error data of the satellites, delay data of the ionosphere, delay data of the troposphere, sets a regression equation of the explanatory variables and the objective variables, and estimates at least the position of the receiver by applying a parameter estimation algorithm to the regression equation.