| 摘要 |
PURPOSE: To employ a local oscillator having relatively low stability by calculating the difference of apparent Doppler frequency shift between a carrier signal transmitted from one satellite and measured at a first time and a carrier signal transmitted from another satellite and measured at same time as the first time. CONSTITUTION: The receiver 10 is provided with a 'receiving channel' comprising an L band antenna 20, a first amplifier 22, an image reject mixer 24 and a local oscillator 26 of relatively low stability. The receiver 10 is also provided with a 'tracking channel' TC 98 comprising a phase control pseudo random noise code signal synthetic unit 52, and a frequency control Doppler shift pseudo signal synthetic unit 54. The receiver 10 comprises at least one TC and the additional TCs 110, 112, 314 and 116 are also connected with a microcomputer MC 70. The MC 70 calculates a number representative of the difference of apparent Doppler frequency shift between a carrier signal transmitted from one and measured at a first time and a carrier signal transmitted from another satellite and measured at same time as the first time. |
