Lesson 8 - Navigation and time

NS100NS100

Introduction to Introduction to Navigation and TimeNavigation and Time

Objectives1. Understand the terrestrial coordinate

system as used to determine position on the surface of the earth.

2. Understand the concepts of latitude and longitude, and how distances and direction on the surface of the earth are computed.

3. Understand time and time zones in navigation.

Reference Points and Lines

Axis

Poles

Great Circles

Equator

Meridians

Small circles

Reference Points

Prime Meridian

Equator

North Pole

South Pole

Longitude line

Latitude line

Coordinate System

Position - Latitude and LongitudeExample: Degreeso Minutes’ Seconds”

39o 58’ 55” N 075o 28’ 45” W

Rhumb Lines & Great Circles

Rhumb line

Great Circle

Equator

- - - - - - - - - - -

X W V U T S R Q P O N Z A B C D E F G H I K L11 10 9 8 7 6 5 4 3 2 1 0 1 2 3 4 5 6 7 8 9 10 11

+ + + + + + + + + + +

+12 Y -12 M

+12 +11 +10 +9 +8 +7 +6 +5 +4 +3 +2 +1 0 -1 -2 -3 - 4 -5 -6 -7 -8 -9 -10 -11 -12

Y X W V U T S R Q P O N Z A B C D E F G H I K L M

Time DefinitionsDaylight Savings Time –

SPRING AHEAD , FALL BACK+5 becomes…

+4-9 becomes…

-10

International Date Line

Used as a convenience.

“If its SUNday in SAN Francisco, it’s MONday in

MANilla”

Date Time Group FormatDate Time Group (DTG) - This format is used on virtually all military message traffic. The format is as follows:

DDTTTTZMONYR

241300ZJAN04

Arc to Time Conversions

ARC TIME15 deg 1 hr1 deg 4 min

(1 deg =60’) 60’ 240 sec(1min=60sec)

1’ 4 sec