Advanced Navigation

1
Advanced Navigation
Celestial Theory
2
Objectives
1. To become familiar with the relationships of
the earth to the solar system and the
universe. 2. To become familiar with the
celestial and horizon coordinate systems,
and how they relate to the terrestrial
coordinate system. 3. To gain a working
knowledge of the celestial and navigation
triangles.
3
Objectives
4. To become familiar with the concept
involved with a circle of equal altitude.
4
THE CELESTIAL SPHERE
5
CONCENTRIC TO THE EARTH
Infinite radius
6
CELESTIAL POLES
NCP
SCP
7
CELESTIAL EQUATOR
EQUINOCTIAL
8
CELESTIAL MERIDIAN
9
CELESTIAL BODIES
STARS
MOON
VENUS MARS JUPITER SATURN
SUN
PLANETS
10
HOUR CIRCLES
11
CELESTIALCOORDINATES
12
DECLINATION
The arc of an hour circle between the celestial
equator and the celestial body, measured
northward or southward from the
equinoctial through 90º
13
DECLINATION
14
HOUR ANGLES
Angular distance west of a celestial meridian
or hour circle the arc of celestial equator, or
the angle at the celestial pole, between the
celestial meridian or hour circle and the hour
circle of a celestial body measured westward
from 0º to 360º
15
HOUR ANGLES
GHA
GHA
GREENWICH HOUR ANGLES
16
Aries
Ecliptic
17
HOUR ANGLES
SHA
SHA
SIDEREAL HOUR ANGLES
18
HOUR ANGLES
LHA
LHA
LOCAL HOUR ANGLES
19
NOW LETS ADD MOTION TO THE SCENE
20
EARTH MOTION
21
IT APPEARS TO BE FROM EAST TO WEST
22
BECAUSE OF THE DIURNALMOTION (EARTHS ROTATION)

• ALL THE CELESTIAL BODIES SEEM TO MOVE AT ONE
  RATE, THEREFORE THE GHAs WILL CHANGE AT ONE RATE
  AND THE RATE IS
• 15DEG -------1HR
• 360DEG ------24HRS

23
GREENWICH HOUR ANGLE
OF THE STAR
OF ARIES
OF THE SUN
First meridian
24
HOUR ANGLES...
SHA
SHA
BECAUSE AND MOVE AT THE SAME RATE
25
GREENWICH HOUR ANGLE
OF THE STAR
OF ARIES
GHA GHA SHA
SHA
26
LOCAL HOUR ANGLE
OF THE STAR
OF ARIES
OF THE SUN
Local meridian
27
LOCAL HOUR ANGLE
OF THE STAR
OF ARIES
LHA LHA SHA
SHA
28
BOTHTOGETHER
29
LHA
LHA
LHA
LONGITUDE
Local meridian
First meridian
30
GHA LHA LONGITUDE LONGITUDE
() WEST / (-) EAST
LHA
LONGITUDE
SHA
31
LONGITUDE () WEST / (-) EAST
LHA
LHA
LONGITUDE
SHA
GHA LHA LONGITUDE GHA LHA
SHA LONG
32
BUT THIS CELESTIALCOORDINATE SYSTEMWASNT
ENOUGH, WE NEEDED A SYSTEM FROM THE
OBSERVERSPERSPECTIVE
33
SOMETHING LIKE THIS
34
SOMETHING RELATED TO THE OBSERVER
35
THEHORIZON COORDINATE SYSTEM
36

• First, well define two points.
• 1. The ZENITH directly above the observers
  head (vertical)

37
ZENITH
38
2. The NADIR directly under his feet. The
line that links both points forms an axis.
39
ZENITH
NADIR
40

• Now well define the OBSERVERS HORIZON the
  plane perpendicular to that axis passing through
  the observer.

41
ZENITH
HORIZON
NADIR
42

• Also the projection of the poles over the
  horizon will give us the other coordinate.

43
-N-
44
ZENITH
OBS. HORIZON
NADIR
45

• Another plane parallel to the Obs. Horizon but
  passing through the center of the earth is called

CELESTIAL HORIZON
46
ZENITH
HORIZON
CELESTIAL HORIZON
NADIR
47
HORIZON
ZENITH
NADIR
CELESTIAL HORIZON
48
HORIZON
ZENITH
CELESTIAL HORIZON
NADIR
49
ZENITH
CELESTIAL HORIZON
NADIR
50
CEL. BODY
OBS. HORIZON
ALTITUDE
51

• The earths radius related to distance to stars
  is negligible so we can consider the Obs. Horizon
  and the Cel. Horizon the same.

52
ALTITUDE
CELESTIAL HORIZON
VERTICAL CIRCLE
53

• The projection of the North pole over the
  horizon will give us the North Cardinal Point and
  from that north we measure the true azimuth

54
CEL. BODY
-N-
ALTITUDE
TRUE AZIMUTH
55
TRUE AZIMUTH
ALTITUDE
PRINCIPAL VERTICAL
CELESTIAL HORIZON
56

• This is the same as this

57
TRUE AZIMUTH
ALTITUDE
PRINCIPAL VERTICAL
CELESTIAL HORIZON
58

• Now we will correlate both coordinate systems

59
NCP
TRUE AZIMUTH
-Z-
ALTITUDE
PRINCIPAL VERTICAL
Horizon coordinate system
CELESTIAL HORIZON
-N-
60
AND
61
LONGITUDE
SHA
Celestial coordinate system
Local meridian
First meridian
62
NCP
-Z-
LHA
LONGITUDE
SHA
Local meridian
First meridian
-N-
SCP
63
NOW WELL DEFINE ANOTHER ELEMENT
64
THE PLACE WERE A LINE LINKING THE CELESTIAL BODY
65
AND THE CENTER OF THE EARTH
PUNCHES ITS SURFACE
66
THE NAME OF THAT POINT IS
GP
GEOGRAPHIC POSITION
67
CELESTIAL TRIANGLE
68
TRIANGLESHAVETHREEVERTICES
69
NCP
ELEVATED POLE
70
NCP
CEL. BODY
CELESTIAL BODY
71
NCP
-Z-
CEL. BODY
OBSERVERS ZENITH
72
TRIANGLESHAVETHREESIDES
73
NCP
-Z-
CEL. BODY
CO- ALTITUDE
74
-Z-
CO- ALTITUDE
90-ALTITUDE
75
NCP
-Z-
CEL. BODY
CO- LATITUDE
76
-Z-
CO- LATITUDE
90- LATITUDE
77
NCP
-Z-
CEL. BODY
POLAR DISTANCE
78
NCP
-Z-
POLAR DISTANCE
CEL. BODY
90/-DEC IF DEC AND LAT SAME NAME PD 90-DEC
IF DEC AND LAT CONTRARY NAME PD
90DEC
79
TRIANGLESHAVETHREE INNER ANGLES
80
MERIDIAN ANGLE
-t-
81
MERIDIAN ANGLE
-t-
RELATED TO THE LHA IF LHA lt 180 THEN t LHA IF
LHA gt 180 THEN t 360 - LHA
82
NCP
-Z-
LHA
LONGITUDE
SHA
Local meridian
First meridian
-N-
SCP
83
NCP
-Z-
LHA
LONGITUDE
SHA
Local meridian
First meridian
-N-
SCP
84
(No Transcript)
85
Questions?
86
Compliments of Curtis Senior High School NJROTC