| 摘要 |
<p>A passive aircraft monitoring system (20) receives signals transmitted by an instrument landing system (14, 16) and reflected from aircraft (18). The Doppler shift in the reflected signals is used to calculate the position or velocity of the aircraft. Using the ILS 90 and 150 Hz signals reflected from the aircraft and comparing their magnitude, the altitude and lateral position of the aircraft can also be determined.</p> |
