Nutating means to spin without affecting the polarisation. This can cause amplitude shifts and hence, is undesirable. This is because we need to maintain the plane of polarization. The data from this circuit drives the servo motors that control the antenna.Ī nutating feed design is given preference over a rear feed design in the conical scan. This data from the echo signal is sent to an angle-error detector circuit. Correspondingly, this causes a change in the amplitude of the reflected signal too. However, if you start moving a bit towards the left or right, your position relative to the axis changes. If you are the centre of this circle constantly then the amplitude of the reflected signal will be constant. Then you would see it tracing the shape of a circle. If you are standing at point A and look at the lobe. Let’s take a look at the different elements of the beam that we use in a conical scan. This motor is kept in a housing or enclosure at the end of the dish. This beam can be achieved by using a rotating feed that is driven by a motor. The rotating beam of a conical scan traces out the shape of a cone. The tracking radar has a system of motors that change the direction of the beam based on the data it acquires from the error signal. We use the data that we get from an error signal to position the antenna beam. Additionally, the positioning of the antenna beam is done by a sort of a feedback mechanism.
This form of tracking is known as angle tracking.īasically, in a tracking radar, we use a signal to locate the position of the object. And we gain this information from the error signal that generates when the beams are slightly off target. But to accurately track the object more information is needed to determine which direction the antenna should move in. In a normal radar, the object is in the beam of the radar and the location and angle can be measured. Why though, you might wonder? The purpose here is to develop a system that can track an object. What is low angle tracking? What is angle tracking?Īll the tracking radars that we discuss here mono pulse, conical scan radar, sequential lobing employ beams that are slightly off target.
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