Types of anternna tracking methods are:

1- Angle tracking

• Sequential lobing
• Conical scan
• Amplitude compression monopulse
• Phase compression monopulse

2- Range tracking

• Sequential lobbing

• Sequential lobing is often referred to as lobe switching or sequential switching.

• Accuracy depends on the pencil beam width. Measuring the difference between the echo signals voltage levels. It is very simple to implement.
• The difference between the echo signals voltage in (A) and (B) equal zero, that’s mean zero error signal.
  1. When the target being on the LOS

1. When the target being off the LOS

1. Conical scanning: It’s an extension of sequential lobbing.

• Some older tracking radar uses the conical scanning principle.
• A conical scan pattern, as shown can be generated by using a rotating feed driven by a motor in the housing at the rear of the dish.
• The axis of the radar lobe is made to sweep out a cone in space; the apex of this cone is, of course, at the radar transmitter antenna or reflector.
• At any given distance from the antenna, the path of the lobe axis is a circle. Within the useful range of the beam, the inner edge of the lobe always overlaps the axis of scan.
• If the target is on the scan axis, the strength of the reflected signals remains constant (or changes gradually as the range changes). But if the target is slightly off the axis, the amplitude of the reflected signals will change at the scan rate.
• For example, if the target is to the left of the scan axis, as shown in the following animation the reflected signals will be of maximum strength as the lobe sweeps through the left part of its cone; the signals will quickly decrease to a minimum as the lobe sweeps through the right part.
• Information on the instantaneous position of the beam, relative to the scan axis, and on the strength of the reflected signals is fed to a computer.
• Such a computer in the radar system is referred to as the angletracking or angle-servo circuit (also angle-error detector).
• If the target moves off the scan axis, the computer instantly determines the direction and amount of antenna movement required to continue tracking.
• The computer output is used to control servomechanisms that move the antenna. In this way, the target is tracked accurately and automatically.