| 摘要 |
PROBLEM TO BE SOLVED: To precisely estimate measurement errors in autonomous navigation even when an absolute position and an absolute velocity are not acquired by radio navigation or when positioning accuracy by the radio navigation is low. SOLUTION: It is determined whether or not the absolute positioning information acquired by the radio navigation is at high reliability on the basis of the number of satellites, from which the radio waves are received, arrangements, and so forth (step S2). In the case of high reliability, the absolute positioning information by the radio navigation is used to estimate the measurement errors of the positioning result by the autonomous navigation (step S4). When the absolute positioning information by the radio navigation is not at high reliability, a high-reliability satellite having reception power or an elevation angle larger than a threshold is selected from among the captured satellites (step S5). A pseudo distance to the high-reliability satellite and a Doppler frequency are calculated and utilized to estimate the measurement errors of the positioning result by the autonomous navigation (step S6). The positioning result by the autonomous navigation is corrected using the estimated measurement errors, and the measured position of a positioning apparatus 10 body is acquired. COPYRIGHT: (C)2007,JPO&INPIT |
