circular scan

circular scan

circular scan
A radar scan pattern in which a given point on the directed beam describes a circle in space with antennae at the center. This scan pattern is used in search radars and is distinguished by the regular intervals between successive illuminations of the target.
References in periodicals archive ?
To assess RNFL thickness, a circular scan concentric to the ONH is performed.
The latter hypothesis was derived from the notion that if a fixed-diameter circular scan is used, the distance between the scan and the ONH margin will be reduced in the presence of a large ONH, which would lead to overestimation of RNFL thickness in patients with large ONH as the measurement would be made closer to the optic disc edge.
It is likely that the positive correlation between ONH size and RNFL thickness depends on the distance between the OCT circular scan and the ONH margin.
46mm circular scan is placed automatically around the optic disc and the information about peripapillary RNFL thickness is obtained.
The ground-based search radar antenna will typically rotate 360 degrees in azimuth, a circular scan.
In addition, depending on the size of the optic disc, the distance from the circular scan to the disc margin varies, and the RNFL becomes thinner as it gets away from the disc margin, which may result with some errors when measuring the thickness.
As shown in Figure 1, the sector scan differs from the circular scan in that the antenna moves back and forth across a segment of angle.
The Palmer scan is a circular scan that is moved linearly, as shown in Figure 3.
In this case, as shown in Figure 4, the threat antenna is assumed to have a circular scan with the elevation arbitrarily moved by a vertical phased array, furnishing a constant time interval between main lobes, but their amplitude can vary without any logical sequence.
The photographic quality of circular scans provides images that an operator could use to identify objects with high confidence.