Furuno FR-1710 manual Electronic Plotting Aid EPA, Plotting a target

1.25 Electronic Plotting Aid (EPA)

10operator-selected targets can be plotted electronically to assess their motion trend. Five past positions can be displayed for each of the plotted targets. If you enter a 6th plot on a certain target, the oldest plot (past posi- tion) will be erased.

A vector appears when you enter a second plot for the target and is updated each time a new plot is entered. The vector shows the target motion trend based on its latest two plots.

Target data is shown in the data display area which shows range, bearing, course, speed, CPA and TCPA of the last-plotted or selected target.

					Target data
						Plotting time
		340 350 000 010 020					RNG
		330		030			BRG
		320			040
						TRUE VECTOR	CRS
310					050
		See note	1			30sec	SPD
300					060		CPA
						1
		below.		2			TPCA
290					070
280	See note				080		00:25
270	below.				3
					090
260					100
250		Echo Watch Zone			110
240					120
	230				130
		220			140

210150

200 190 180 170 160

EPA symbols

:Target plotted

:Target plotted and data indicated.

: Target on a collision course

Note:

Target 2 is on a collision course as the extension of its vector goes through the own ship position. Placing the offset EBL will help for assessment.

TCPA is counted up to 99.59 min and beyond that it is indicated as TCPA > 99.59 MIN.

Figure 1-25 EPA display

Note: The EPA requires speed input (auto- matic or manual) and a compass signal. The vector and data are updated on real time be- tween plot entries, but do not neglect to plot a new position over a long period of time. Otherwise, the accuracy will be reduced. Note that the plots will be lost when the compass fails; start the plotting exercise again.

Plotting a target

1.Place the cursor on a target of interest by operating the trackball.

2.Press the [ACQ] key. A plot symbol (circle) and target number (0-9) appears on the target.

3.Watching the EPA time shown at the right side of the screen, wait for at least 30 seconds. Place the cursor (+) on the plot symbol with number and then press the [ENTER/SELECT] key. The symbol shape changes from circle to square and the target number in the data display flashes.

4.While the target number is flashing, place the cursor on the target and press the [ACQ] key. The plot symbol moves to the new target position and the previous po- sition is marked by a small dot.

5.To acquire other targets, repeat the above steps selecting different plot symbols.

6.If the target echo separates from its plot symbol, repeat steps 3 an 4.

Note: If a target once plotted is not plotted again within 10 minutes, the warning “UP- DATE PLOT” and Plot No. will appear on the upper right margin of the screen and the plot symbol of the target flashes. If you want to continue plotting this target, reacquire it within five minutes. Otherwise, the target will be re- garded as a “lost target” and its plot symbol and target data will be erased. The larger the plotting interval, the less accurate the plot- ted target data. Plotting of each target should normally be made every 3 or 6 minutes as far as possible. You can use the Time Alarm to warn yourself every 3 or 6 minutes.

Within 30 seconds, you can cancel a last plot by the [CANCEL/CLEAR] key and make a re-entry at a different position. After 30 sec- onds, the last entry is processed to produce a vector.

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