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Other Electronic Navigation Equipment
SINS
Radio Direction
Finders
SINS (Ship’s Inertial Navigation System) is the process of directing the
movements of a rocket, ship, aircraft, or other vehicle from one point to
another, based on sensing acceleration of the vehicle in a known spatial
direction with the aid of instruments that mechanize the Newtonian laws
of motion, and integrating acceleration to determine velocity and
position.
SINS is an accurate, all-weather, dead reckoning system. It employs
gyroscopes, accelerometers, and associated electronics to sense turning
rates and accelerations associated with the rotation of the Earth, and with
ship’s movement relative to the surface of the Earth.
Radio beacons were the first electronic aid to navigation. The basic
value of the radio beacon system lies in its simplicity of operation and
its relatively low user costs, even though the results obtained may be
somewhat limited. The Radio Direction Finder (RDF) is a specially
designed radio receiver equipped with a directional antenna. The
antenna is used to determine the direction of the signal emitted by a,
shore station, relative to the vessel. A radio beacon is basically a
short-range navigational aid, with ranges from 10 to 175 nautical miles.
Bearings can be obtained at greater ranges, but they are usually of
doubtful accuracy and should be used with caution. When the distance
to a radio beacon is greater than 50 miles, a correction is usually applied
to the bearing before plotting on a Mercator chart. These corrections, as
well as information on the accuracy of bearings, plotting, and other
matters, are contained in DMA publication 117, Radio Navigational
Aids.
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