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The operating principle of the channel bearing the phase measurement method⇐ ПредыдущаяСтр 15 из 15
The antenna system has APM pict (a) horizontal beam shape close to a circle which is offset with respect to the center of APM. Rotation of the diagram at an angular velocity
Figure 3.2 The radiation pattern of the antenna phase ARM (a); azimuth signals received at points 1 and 2 (b); spectrum of the received signal (in and On board equipment block diagram) The basic equation of ARM that implements phase method of determining azimuth, has the form By measuring the phase of the envelope of the received signal, it is possible to directly determine the azimuth of the point of reception. It follows that the determination of the azimuth error is numerically equal to the phase measurement error. For phase measurement on LA with APM transmit a reference signal which is frequency-modulated subcarriers with an average frequency oscillations kHz. Modulating voltage signal is at a frequency of 30 Hz at a constant phase corresponding to the phase of the signal received at the workstation from a northerly direction. Thus, the signal at the point of APM with the azimuth is given by
where - The onboard equipment of aircraft detected, ARM signal Rx receiver divided filters F30 and F10, respectively tuned to the frequency and. From the reference signal after the frequency detector BH stands constant phase signal with a frequency that is supplied to the IF phase meter, which served as the azimuth signal of the same frequency. Accuracy azimuth phase channel. Accuracy of the channel depends mainly on the change in the azimuthal phase of the signal at its interference with signals reflected from surrounding objects APM. Assuming that only one such object with a complex coefficient reflection
where
where -
For example, if
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