Raytheon Anschuetz GmbH High Seas Products NSX-30U 用户手册
Synapsis Radar
with Nautoscan NX Pedestal
Operator Manual
Edition Sep 2015
2-43
4265.DOC020102
2.3.1.4
Sea
The Sea control is used to suppress Radar returns which are the result of
Radar signals reflected from waves. This effect is commonly known as sea
clutter.
The Sea control is used to suppress Radar returns which are the result of
Radar signals reflected from waves. This effect is commonly known as sea
clutter.
The effects of sea clutter are greater (more reflected energy) at close range and
vary with wave height and wind. It should also be noted that sea clutter is
reduced on the leeward side of the ship as the retreating wave fronts do not
provide as many Radar returns as oncoming waves.
vary with wave height and wind. It should also be noted that sea clutter is
reduced on the leeward side of the ship as the retreating wave fronts do not
provide as many Radar returns as oncoming waves.
Small targets (buoys, etc.) often return nearly the same energy as do the waves
and can, therefore, be lost in the clutter. However, since sea clutter is random
in nature, the gain and clutter processing circuitry together with the SEA control
allow the operator to reduce the sea returns to a light background speckle at
low brightness level while maintaining targets in the sea clutter at full
brightness.
and can, therefore, be lost in the clutter. However, since sea clutter is random
in nature, the gain and clutter processing circuitry together with the SEA control
allow the operator to reduce the sea returns to a light background speckle at
low brightness level while maintaining targets in the sea clutter at full
brightness.
The effect of the Sea control is greatest at short range. Its effect reduces
progressively as the range increases. At a range determined by the height of
the Radar antenna above the water (and other factors), the effect of the SEA
control ceases altogether. This is typically about 8- 10 NM.
progressively as the range increases. At a range determined by the height of
the Radar antenna above the water (and other factors), the effect of the SEA
control ceases altogether. This is typically about 8- 10 NM.
The ideal sea control setting will reduce sea returns to a light speckle. Scan- to-
scan integration will keep the sea returns at a low brightness level, while targets
in the sea clutter will be shown at full brightness.
scan integration will keep the sea returns at a low brightness level, while targets
in the sea clutter will be shown at full brightness.
The sea clutter control should be adjusted in small increments, with pauses to
observe 3 scans for the results.
observe 3 scans for the results.
In heavy sea clutter, some clutter peaks may come through at brighter levels,
especially rollers, so an average setting should be chosen. It is important to
note that if the Sea Clutter control is adjusted to completely remove all clutter,
then some targets may not be detected.
especially rollers, so an average setting should be chosen. It is important to
note that if the Sea Clutter control is adjusted to completely remove all clutter,
then some targets may not be detected.
The Radar uses gyro and speed information as part of the
clutter removal process. It is therefore highly recommended
that you use gyro stabilization and ensure that the manual
speed or speed log input is accurate.
clutter removal process. It is therefore highly recommended
that you use gyro stabilization and ensure that the manual
speed or speed log input is accurate.
In heavy wind driven seas where more sea clutter appears on the windward
side of the ship, a slight amount of FTC can balance the clutter (chapter
2.3.1.7) before adjusting the SEA control. If too much SEA is applied during
periods of light clutter, then a band of noise could appear on the edges of the
sea clutter.
side of the ship, a slight amount of FTC can balance the clutter (chapter
2.3.1.7) before adjusting the SEA control. If too much SEA is applied during
periods of light clutter, then a band of noise could appear on the edges of the
sea clutter.