Northrop Grumman Sperry Marine VisionMaster FT, User Manual

Page: 179 / 533

Radar/Chart Radar User Guide Navigation Tools
65900010 6-37
Line of Position
The geographic location of own ship can be determined by using Lines of
Position (LOP), which are created by taking bearings and/or radar
measurements from own ship to suitable objects. Visual bearings taken on
fixed aids to navigation or landmarks such as smokestacks or towers are
typically used for bearing LOPs, while the distance to a distinct shoreline or
point of land measured by radar may be used for a range LOP. When two
or more LOPs are created a fix of own ship’s position may be obtained.
An active point symbol will be displayed at each of the operator-defined
LOP positions. Each symbol includes a reference number i.e. LOP 1, LOP
2 etc. When the range of bearing data is entered, the time of entry is
indicated beside the symbol. The symbol remains fixed at the selected
location or charted object, but the time stamp moves with the line or circle,
based on the speed and course of the vessel.
Up to six LOPs may be drawn on the chart display.
Creating LOPs
To generate one or more LOPs, do the following:
1. Click on Nav Tools in the main menu, and then select Line Of
Position in the Nav Tools menu list. If no LOPs have been
previously created, the window opens prompting to right click on
the display to select a LOP position. Or, if
LOPs have been left over from a previous
LOP fix, click the
Clear button.
2. Right click on the display at the desired
LOP reference point and click Add Line of
Position (LOP) in the semi-transparent context menu that appears.
The Line Of Position menu will show the Lat/Long of
the clicked location and a list of charted objects
detected near the clicked location. Normally one of
the objects in the list represents the desired object
that the range or bearing will be measured to,
although clicked location, or a specified lat/lon may
also be used.
3. Either select the object/location from the list;
or, specify a Lat/Long position. Manually
Specified Below is automatically
highlighted when Lat/Long data is entered.