Download - Nav Gyro Error by Celestial 1
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NN 204NN 204Advanced NavigationAdvanced Navigation
Gyro Error by CelestialGyro Error by Celestial
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Gyro Error by CelestialGyro Error by Celestial
Objectives:
1. Understand the importance of determininggyro error and the periodicity in which it is
determined.
2. Review the methods of determining gyro
error when piloting.
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Objectives:
3. Demonstrate the method of determining gyro error by sing ! observing the sn.
". Demonstrate the method of determining gyro error by sing ! observing #olaris.
$. Discss the advantages and limitations ofsing the amplitde e%ation to determine
gyro error.
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Objectives:
&. Discss the best time to observe a body for the prpose of obtaining an amplitde to
determine gyro error.
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Review
'yro error is the difference between the
directions indicated by the gyro compass(
and the respective tre directions.
)est *rror
+f the ship were
on a corse of ,,,pgc( it wold be
pointed left -west
of tre /orth.
*ast *rror
+f the ship were on
a corse of ,,,pgc( it wold be
pointed right -east
of tre /orth.
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Review
0+f 'yro is east( error is *ast.
0+f 'yro is est( error is )est.
'yro bearing 4 *asterly error 5 6re bearing
' 4 * 5 6
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7ethods of determing
'yro *rror6he easiest way of determining gyro error isto compare the compass bearing to an object
with its 8nown -tre bearing. 6hree ways ofdoing this celestially are:
9 *act ;
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Amplitude Method
6his method can be sed when the observed
body is rising or setting( as long as its
declination does not eceed 2" degrees.
6he amplitde is defined as the hori
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Amplitude Method
;dvantages:
1. 6he simplicity of ta8ing an a
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Amplitude Method
6o determine the amplitde angle -; se thefollowing formla:
; 5 arcsin -sin Dec ! cos at
6he reslt( ;( will be epressed with a letter
prefi and sffi. * or ) will precede the
angle( depending on whether the body is rising-*ast or setting -)est. 6he sffi will be
0/ if the body has a north declination( or 0>
if its declination is soth.
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Amplitude Method
6o convert amplitde angle to a tre aoth of )est 2A, @ ;
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olaris
#olaris( called the north star( is always
within 2 degrees of tre north.Balclating the tre a
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!uestions"