Furuno 1834C-BB User Manual

Page of 233
2. RADAR OPERATION 
 
2-26
2.26  ARP, TTM Operation 
When the radar source is an ARP-equipped Model 18x4-BB/19x4-BB series network radar, 
you can manually and automatically acquire and track ten targets. Once a target is acquired 
automatically or manually it is automatically tracked within 0.1 to 32 nm. If the FURUNO 
heading sensor PG-1000 is used, the data sentence “RMC” is necessary. 
 
Alternatively, you can display the tracks of other ships by receiving the data sentence TTM 
(Tracked Target Message) via the NETWORK or NMEA port on the processor unit. 
However, targets cannot be acquired. 
 
Note:
 When using your unit as remote display, you cannot change the range of the main 
radar at the remote display. For the target acquisition, set the range individually.     
 
Usage precautions for ARP
 
No one navigational aid should be relied 
upon for the safety of vessel and crew.
The navigator has the responsibility to
check all aids available to confirm
position. Electronic aids are not
a substitute for basic navigational
principles and common sense.
• 
This auto plotter automatically tracks an
   automatically or manually acquired radar
   target and calculates its course and
   speed, indicating them by a vector. Since
   the data generated by the auto plotter
   are based on what radar targets are
   selected, the radar must always be
   optimally tuned for use with the auto
   plotter, to ensure required targets will not
   be lost or unwanted targets such as sea
   returns and noise will not be acquired
   and tracked.
• 
A target does not always mean a land-
  mass, reef, ships or other surface vessels
  but can imply returns from sea surface
  and clutter. As the level of clutter changes
  with environment, the operator should
  properly adjust the A/C SEA, A/C RAIN
  and GAIN controls to be sure target
  echoes are not eliminated from the
  radar screen. 
CAUTION
The plotting accuracy and response of
this auto plotter meets IMO standards.
Tracking accuracy is affected by the
following:
 Tracking accuracy is affected by course
   change. One to two minutes is required to
   restore vectors to full accuracy after an
   abrupt course change. (The actual
   amount depends on gyrocompass
   specifications.)
 The amount of tracking delay is inversely
   proportional to the relative speed of the
   target. Delay is on the order of 15-30
   seconds for high relative speed; 30-60
   seconds for low relative speed.
Display accuracy is affected by the
following:
 Echo intensity
 Radar transmission pulsewidth
 Radar bearing error
 Gyrocompass error
 Course change (own ship or target)
CAUTION