Range And Bearing Measurements - Raytheon Pathfinder 1200 Instruction Manual

2.2 RANGE AND BEARING MEASUREMENTS (See Figure 2-2)
The picture on the screen shows a plan view of the position of targets around your
vessel. In effect your ship is at the center of the screen and targets are presented in polar
coordinates (or map-like) throughout 360 degrees. The display is referred to as the PPI
(Plan Position Indicator).
2.2.1 Range Measurement
To measure a target's range proceed as follows:
I) Note the range scale in use and the distance between rings.
2) Count the number of rings between the center of the screen and the target, and visually
estimate the distance between the inner edge of the target and inner edge of the nearest
ring.
2.2.2 Bearing Measurement
Using bearing scale engraved on the screen filter, read the bearing where the radial line
passes through the center of the target. The reading you obtain will show the targets re-
lative bearing in degrees.
2-4
SHIP's HEADING MARKER
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27~H----+-----l---+---o---*--+----t---+~
RANGE RINGS
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FIG. 2-2 RANGE AND BEARING MEASUREMENTS
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TARGET
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