Furuno 1724C, 1734C manual 25 ARP, TTM Operation, Usage precautions for ARP

2. RADAR OPERATION

2.25 ARP, TTM Operation

When the radar source is an ARP-equipped Model 18x4/19x4 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 16 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.

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

CAUTION

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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