| 摘要 |
PROBLEM TO BE SOLVED: To detect even a satellite which is impossible to be detected by using a its positional information just before the reception becomes impossible because the reception level of the satellite which is possible to be received is reduced. SOLUTION: An advancing-direction operation part 12 detects the radio wave doppler shift of every satellite from the output signals of a GPS reception part 11 which receives radio waves of every satellite through an antenna 10 and it operates the advancing direction P of a mobile body, then it sends the direction to an indication control part 14. In addition, a satellite information detection part 13 obtains the azimuth and elevation of a satellite which can be received according to the output signals and detects the position and reception status of every satellite. The control part 14 finds the relative angles between the positions P and respective satellites in order to prepare a newly corrected data for indication. The indication part 15 draws the sky position of the respective satellite by using the data and indicates it together with the reception status. Then, in case where there is no satellite that can be received, the value just before the reception level becomes lower among the results that the detection part 13 stores every time is adopted so as to find out the position of a satellite which cannot be received and draw it. Thus, the satellite which cannot be received can be detected. |
