| 摘要 |
<p>The conventional FM-CW mode radio apparatus combines transmitted and reflected waves to acquire a beat signal and determine a Doppler velocity from a frequency transition corresponding to a relative velocity of the object included in the beat signal. However, in a case of performing weather observations of clouds, rain and/or the like, the frequency deviation corresponding to a relative velocity is very small relative to the frequency deviation proportional to a distance, so that it is extremely difficult to measure the distance and relative velocity of an object only on the basis of the frequency component of a beat signal. In order to solve this problem, an FM-CW radio apparatus is provided which comprises: an FM wave transmitting unit for transmitting FM waves that are repetitively frequency-swept; a reflected wave receiving unit for receiving reflected waves; a beat signal synthesizing unit for synthesizing a beat signal from the transmitted and reflected waves; an initial phase acquiring unit for acquiring the initial phase of the beat signal in each of a plurality of sweepings; and a Doppler velocity candidate acquiring unit for acquiring a Doppler velocity candidate from the difference between two or more acquired initial phases.</p> |
