Glossary

NNautical Mile (nm): A distance measurement equal to 6,076 feet, or 1.15 statute mile. One nautical mile is also equal to one minute of latitude.

NAVSTAR: The name given to GPS satellites formed from the acronym for NAVigation System with Time And Ranging.

Non-Directional Beacon (NDB): A low frequency/medium frequency navigation aid sending non-directional signals that can be used for navigation.

OOBS: Omni-Bearing Selector.

PParallel Track Offset: A course that is parallel to the designated course, but offset to the right or left by a given distance.

PDOP: Position Dilution of Precision. See Dilution of Precision.

PRN: GPS satellite Pseudo-Random Numbers are used to uniquely identify satellites. This is different than the SVN (Space Vehicle Number, or satellite serial number). When excluding satellites from the RAIM Prediction , use the PRN number found on the NOTAMs and NANUs, not the SVN.

RRadial: Any of the 360 magnetic courses from a VOR or similar navigational aid, beginning at the navigational aid and proceeding outward in a straight line.

RAIM: Receiver Autonomous Integrity Monitoring. A method of predicting possible system accuracy errors that may be caused by bad satellite data. The RAIM algorithm requires that more satellites are available and usable than required for a normal GPS position fix.

Range: The distance from the present position to a destination waypoint.

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