| 摘要 |
<p>PROBLEM TO BE SOLVED: To avoid erroneous speed output by detecting the reception of a side lobe in a direction vertical to an aircraft when the aircraft is flying above the ground in a mirror surface state. SOLUTION: A beam length arithmetic unit 16 input the scanning angle of a beam scanning angle controller 14, the aircraft altitude information of various airplane information sensors 13, and attitude information to calculate a beam length. A beam length change arithmetic unit 17 calculates a beam length change speed according to the beam length, and a correction speed arithmetic unit 18 obtains a speed calculation error (i) according to the beam length change speed and a correction coefficient (k) of the speed calculation error due to the angle between the speed vector and the main beam in beam scanning. Speed correction equipment 19 calculates a speed V based on V=k.Vf-i (Vf: the speed output of Doppler speed arithmetic unit 6) while a beam-scanning signal is being inputted. In this case, while an aircraft is flying above the ground in a mirror surface state, the reception of a main beam is limited to the reflection of a perpendicular side lob only and the speed output Vf becomes nearly zero. In this case, it is judged that the perpendicular side lob is being received and an invalid status in outputted.</p> |
