| 摘要 |
PROBLEM TO BE SOLVED: To eliminate wasteful power consumption by preventing wasteful receiving operation for GPS signals, without fail. SOLUTION: Prior to reception of a GPS signal, the angle and the direction of inclination of a reference axis set for the antenna which are pieces of information representing the attitude/state of the antenna, are detected. Based on the detection results and a direction of a relatively high gain which enables obtaining a gain which is not lower than a predetermined gain in the antenna, a high-sensitivity reception direction which enables obtainment of a high reception sensitivity which is not lower than a predetermined value is identified. Whether there are satellites in a specific area, in the sky in the identified high-sensitivity reception direction, is confirmed based on almanac information, and the reception of the GPS signal is started on condition that existence of a predetermined number of satellites has been confirmed. Namely, GPS-signal receiving operation is performed, only when it is determined that this is an ideal reception environment, while the directivity of the antenna and satellite positions are taken into consideration is secured. COPYRIGHT: (C)2011,JPO&INPIT |
