| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the problem in monopulse tracking that, although an error in azimuth and elevation angles is detected using sum and difference signals generated from a received signal, a difference in group delay between the sum and difference signals causes an error, and that, although an antenna tracking circuit needs to be calibrated in order to avoid this error, but if a narrow band signal such as a continuous wave is used as a calibration signal, uncertainty of its phase gives rise to difficulty in correcting the group delay. <P>SOLUTION: A main reflection mirror 4 of a tracking antenna has an adjustment antenna 12 installed at a known position on its elevation angle axis, from which an adjustment signal 20, or a PSK modulated wave, is radiated. At this time, since the azimuth of the adjustment signal 20 and that of an antenna directional angle match, an azimuth error signal should become 0, so that, in calibrating the antenna tracking circuit, a difference in group delay between a sum signal 15 and a difference signal 16 is corrected in variable delay circuits 22 and 23, whereby the azimuth error signal is adjusted to 0. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
