1. Navigation
NAU 102
Lesson 1

2. Introduction to Navigation
What is “Navigation”?
The means by which a craft is given guidance to travel from one known location to another. (Logsdon)
The art and science of safely and efficiently guiding the movement of a vessel from one place to another.
How is it “science”?
How is it “art”?

3. Categories of Navigation
Piloting
Dead Reckoning
Celestial Navigation
Radio Navigation
Satellite Navigation

4. Categories of Navigation Navigating in restricted waters (near land)
Piloting
Navigating in restricted waters (near land)
Frequent determination of position relative to nearby geographic and hydrographic features.
Visual bearings
Radar ranges
Depth of water

5. Categories of Navigation
Dead Reckoning (DR)
From Deduced (ded.) Reckoning
Deduces position by advancing a known position along a course and speed line.
Predicts where you are or will be based on where you used to be and subsequent courses and speeds.
Ignores effects of wind, current, bad steering, etc.

6. Categories of Navigation (Not covered in this course.)
Celestial Navigation
The use of observations of celestial bodies (Sun, Moon, planets, stars) to determine position.
(Not covered in this course.)

7. Categories of Navigation Hyperbolic navigation systems
Radio Navigation
The use of radio waves to determine position through a variety of electronic devices.
Hyperbolic navigation systems
(Loran – C)

8. Categories of Navigation
Satellite Navigation
The use of radio signals from satellites to determine position.
Global Positioning System (GPS)
GLONASS
Galileo
(Not covered.)

9. Problems of Navigation The job of the navigator is to determine:
Position
Direction
Distance

10. Position – Where am I? An identifiable location on the earth.
Stated relative to a fixed known location.
e.g. 6 miles west of Golden Gate
Or, stated using a coordinate system.
e.g. Latitude & Longitude
Accuracy and reliability vary depending of positioning method.

11. Types of positions, in order of reliability:
Position – Where am I?
Types of positions, in order of reliability:
Fix
Running Fix
Estimated Position
Dead Reckoning

12. A position based on solid information which can be safely relied upon.
Position – Where am I?
Fix
A position based on solid information which can be safely relied upon.
Obtained by crossing (nearly) simultaneous lines of position (bearing or range) from 2 or more objects.
Piloting
Celestial
Radio
Satellite

13. Position – Fix

14. Position – Where am I? Running Fix
A position based on lines of position obtained at different times.
Less reliable than a Fix
Celestial
Piloting
Radio

15. Position – Where am I? Estimated Position (EP)
A DR position corrected using extra information.
Current
Steering errors
Wind
One line of position

16. Direction – Which way?
Direction – angular orientation between two points.
Measured in degrees of arc from a reference.
References:
Geographic North = true direction (T)
Magnetic North = magnetic direction (M)
Ship’s heading = relative direction (R)

17. Direction – Which way? Definitions
Course (C)– intended direction of vessel.
Heading (Hdg.) – direction the vessel is pointed.
Track (Tr) – intended path of travel
Course over ground (COG) – actual path of travel
Course made good (CMG) – resultant direction traveled between 2 points.

18. Direction – Which way?

19. Direction – Which way? Definitions (cont.)
Bearing - Direction of one object to another

20. The spatial separation between two points.
Distance – How far?
The spatial separation between two points.
Unit of measure = nautical mile (nm)
1 nm = 6,076.1 ft = km
1 nm = 1.15 statute mile

21. Distance – How far? Related Concepts: Time – How long will it take?
Speed – rate of movement
1 knot (kt) = 1 nm/hour
Speed X Time = Distance

22. Problems of Navigation
Definitions
Speed of advance (SOA) – intended speed
Speed over ground (SOG) – relative to the earth
Speed through the water (STW) – relative to the water
Speed made good (SMG) – resultant speed between 2 points
Track made good (TMG) – resultant speed and course between 2 points.

23. Introduction to Navigation
Questions?