Patent ID: 8072372

Claim:
A position calculation method comprising: (a) receiving positioning satellite signals; (b) generating a first satellite set and a second satellite set; (c) computing a first candidate position using the first satellite set and a second candidate position using the second satellite set; (d) obtaining a first A Priori Residual (APR) value and a second APR value, the first APR value being a sum of squares of a difference between a first pseudo-range determined based on a signal of a first satellite among the first satellite set and an approximate distance between the first satellite and the first candidate position, the second APR value being a sum of squares of a difference between a second pseudo-range determined based on a signal of a second satellite among the second satellite set and an approximate distance between the second satellite and the second candidate position; (e) averaging the first and second APR values to obtain an APR average value; (f) selecting one of the candidate positions as a present position based on a position threshold associated with the present position; and (g) changing a number of iterations of the steps (c) and (d) based on the APR average value.