Furuno 1943, 1933, 1833 manual 26 ARP, TTM Operation, Display accuracy is affected by the following

2. RADAR OPERATION

2.26ARP, TTM Operation

With the optional ARP circuit board, 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 display unit. However, targets cannot be acquired.

Usage precautions for ARP

WARNING

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)

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