The plan position indicator (PPI) scope display is normally used with circular scan radar The scan durations of early warning radars are relatively long to provide the required “hits per scan” for long-range target detection. Circular scan radars with low PRFs generally use long pulse widths in order to increase their average power and long-range detection capability. This gives the radar system a long, unambiguous range capability. A low PRF allows sufficient time for the radar pulse to travel long distances, and return, before another pulse is transmitted. Since early detection is the primary goal of early warning radars, accurate altitude and azimuth resolution are secondary considerations.Ĭircular scan radars designed for early warning transmit a radar signal with a low PRF. This antenna scan allows the radar to scan large volumes of airspace for early target detection. Since elevation information will normally be provided by height finder radars, the size of the vertical beamwidth is not a limitation. To accomplish these missions, the antenna generates a fan beam that has a large vertical beamwidth and a small horizontal beamwidth. This makes these radars ideal for the roles of early warning and initial target acquisition. The factors that determine the number of hits per scan the radar receives include pulse repetition frequency (PRF), antenna beamwidth, and scan duration.Ĭircular scan radars provide accurate target range and azimuth information. Most pulse radars require 15 to 20 hits per scan to obtain sufficient information to display a target.
#Conical scan raster scan full
Scan duration is the number of “hits per scan,” or the number of pulses, reflected by a target as the radar beam crosses it during one full scan. The time required for the antenna to sweep one complete 360° cycle is called the scan rate. Scan pattern referring to how radars steer their beam across their field of view to search for targetsĪ circular scanning radar uses an antenna system that continuously scans 360° in azimuth.
0 kommentar(er)
