OPERATION OF THE RADAR

Types of Radar Display – Set UP and Maintain Radar Display;

There are two basic displays used to portray target position and motion on the PPI’s of navigational radars. The relative motion display portrays the motion of a target relative to the motion of the observing ship. The true motion display portrays the actual or true motions of the target and the observing ship. Depending upon the type of PPI display used, navigational radars are classified as either relative motion or true motion radars. However, true motion radars can be operated with a relative motion display. In fact, radars classified as true motion radars must be operated in their relative motion mode at the longer-range scale settings. Some radars classified as relative motion radars are fitted with special adapters enabling operation with a true motion display. These radars do not have certain features normally associated with true motion radars, such as high persistence CRT screens.

Relative motion radar:

Through continuous display of target pips at their measured ranges and bearings from a fixed position of own ship on the PPI, relative motion radar displays the motion of a target relative to the motion of the observing (own) ship. With own ship and the target in motion, the successive pips of the target do not indicate the actual or true movement of the target. A graphical solution is required in order to determine the rate and direction of the actual movement of the target. If own ship is in motion, the pips of fixed objects, such as landmasses, move on the PPI at a rate equal to and in a direction opposite to the motion of own ship. If own ship is stopped or motionless, target pips move on the PPI in accordance with their true motion.

True motion radar:

True motion radar displays own ship and moving objects in their true motion. Unlike relative motion radar, own ship’s position is not fixed on the PPI. Own ship and other moving objects move on the PPI in accordance with their true courses and speeds. Also unlike relative motion radar, fixed objects such as landmasses are stationary, or nearly so, on the PPI. Thus, one observes own ship and other ships moving with respect to landmasses. True motion is displayed on modern indicators through the use of a microprocessor computing target true motion rather than depending on an extremely long persistence phosphor to leave “trails”.

The use of the radar controls are counted below:

Joystick: The joystick is used to move the cursor around the display. The joystick is also used to move the pointeron the menus.

Data controls: There are two rotary data controls, either of which increase a value by rotaing clockwise, and decrease a value by rotating counter-clockwise.

VRM/Data: The VRM/Data control is used to change the VRM positions or for general data input when prompted.

EBL/Data: The EBL/Data control is used to change the EBL bearings or for general data input when prompted.

Gain: The gain control is used to vary the levelof the radar signals displayed on the screen.

Anti-clutter sea: With A/C MANUAL selected, the Anti-clutter sea control is used to reduce the clutter appearing on the display due to the radar signals from the sea surface.

Anti-clutter rain: With A/C MANUAL selected, the Anti-clutter rain control is used to reduce the clutter appearing on the display due to the radar signals from the rain surface.

Tune: The tune control is used to manually tune the receiver.

Panel brilliance: The panel brill control is used to set the brilliance of the control panel illumination.

Display brilliance: This control is used to set the brilliance of the display.

Pulse-St by: When in stand by, a short press of the key will switch the radar to transmit, whenin transmit, short press of the key will cycle through the available pulse lengths available on the selected range scale.

Stab-Unstab: When unstabilised, the display is head-up. Pressing the key when unstabilised will change the display to north up, another pressing will change to course-up, and another pressing will change again to north-up. A long press when stabilised will change the display oto head-up.

TM-RM: When in relative motion, a short press of the key changes the display to Fixed Origin True Trails (FOTT). Pressing the key while in FOTT changes the display to true motion. Further short press of the key will change the display between TM and FOTT. A long press selects relative motion. If relative motion is selected, either stabilized or unstabilized maybe selected. If true motion or FOTT is selected only NU and CU may be selected.

Trails-Perm: Short press of the key will set the trails to off, short, and long. A long press of the key will change the trails to permanent.

Auto-Enhance: Short press of the key selects either manual anti-clutter at automatic anti-clutter. Long presses of the key selects enhance on-off exept when range scale is below 0,75 miles.

Center-Shift: A short press centers the radar screen. To shift from the center this key should be pressed continuously, at the same time joystick sholuld be moved to the desired point, and the key should be relaesed.

Hm off: During the press of this key hedeing marker disapears.

EBL/Off: A short press of this key displays EBL1, second short press adds EBL. By presing shift&carring from the menu, EBL can be offset with the joystick.

G zone-Clear: Two guard zones are available. A short press of key selects which of these guard zones is adjustable. A long press of the key clears the zone.

Vector-Time: A short press of the key changes between true and relative vectors.

Cancel: To cancel aplot , use the joystick to position the cursor over the target end of the vector and press the key.

Mark-Clear: A short press of the key places a mark at the cursor position, as set by joystick marks can be cleared by long press of the key with the cursor.

Plot-Select: A short press of the key produces a plot at the position of the cursor, as set by joystick. After 30 seconds a second plot can be made, and target course, speed, CPA and TCPA is displayed. Plots are automatically dropped after 12 minutes.

Range: Two range controls changes the range of the radar.

Index-Clear: One short press produces a parallel index line. This index can be chached using the data controls. A long press of the key will clear the index.

Speed: Pressing this key we can chose manual speed or the speed information took from GGPS.

Rings: Shows the rings.

Alarm ack: This key allow us to acknowledge any given alarm.

Menu: Pressing this key menu will be displayed on the screen.

Enter: Provide us to chose some choices in the menu, and to tour through the menues.