72
4 Measuring Principles and Techniques …
Fig. 4.15 Partial patterns
one earlier examined method of angular coordinates measuring), and a coordinate
in vertical plane is defined in special way—by method of partial directional patterns
(Fig. 4.15).
Radar antenna generates in space a complex ray consisting of a big amount of
narrow beams fanning out in vertical plane. At rotation of fanned beam around vertical
axis, the range and azimuth are measured, exploiting beam narrowness in horizontal
plane. Signals received by separate beams come to corresponding to these beams
receivers. Target elevation angle is roughly determined by beam number (receiver),
by which a reflected signal was received. Updating (refinement) of elevation angle
within a beam is conducted via one of comparison methods examined earlier.
The method disadvantage of partial patterns consists in a complexity of equipment,
stipulated by the following: presence of special units, implementing a comparison
method and accurate measuring of elevation angle; multi-channeling of receiving
equipment; positioning of a huge amount of radiating elements in aperture of common
antenna mirror (reflector).
4.3 Object Velocity Measurement Methods
Doppler velocity measurement method. There are two assigned objectives for
measuring of velocity:
1. Measuring of locating object velocity (in area of radar location).
2. Measuring of actual object velocity (in area of radar navigation).
4 Measuring Principles and Techniques …
Fig. 4.15 Partial patterns
one earlier examined method of angular coordinates measuring), and a coordinate
in vertical plane is defined in special way—by method of partial directional patterns
(Fig. 4.15).
Radar antenna generates in space a complex ray consisting of a big amount of
narrow beams fanning out in vertical plane. At rotation of fanned beam around vertical
axis, the range and azimuth are measured, exploiting beam narrowness in horizontal
plane. Signals received by separate beams come to corresponding to these beams
receivers. Target elevation angle is roughly determined by beam number (receiver),
by which a reflected signal was received. Updating (refinement) of elevation angle
within a beam is conducted via one of comparison methods examined earlier.
The method disadvantage of partial patterns consists in a complexity of equipment,
stipulated by the following: presence of special units, implementing a comparison
method and accurate measuring of elevation angle; multi-channeling of receiving
equipment; positioning of a huge amount of radiating elements in aperture of common
antenna mirror (reflector).
4.3 Object Velocity Measurement Methods
Doppler velocity measurement method. There are two assigned objectives for
measuring of velocity:
1. Measuring of locating object velocity (in area of radar location).
2. Measuring of actual object velocity (in area of radar navigation).