1. Lesson 20: Advanced Navigation Systems
“Getting Acquainted Lecture”
Instructor Bio:
Commissioned May, 1993; NROTC Unit, IIT
Reported to Hue City (CG-66) homeported in Mayport, FL for a 42 mos tour
24 mos - Engineering Dept (Auxiliaries Officer & Damage Control Assistant)
18 mos - Operations Dept (Air Warfare Officer/BW Flag Liaison Officer)
Command Employment (while aboard Hue City)
1995 Med Deployment 95-2 with USS Theodore Roosevelt
1996 Baltops ‘96 (Scandinavian countries)
1997 Med Deployment 97-2 with USS John F. Kennedy
Midshipmen Cruises (emphasize student contribution to course)
CV (CV 63) - Secrest
Tico’s (LKE, VLG) -Waterston, Pope, Sullivan
Burkes (DDG 61) - Kuckel
OH Perry (FFG 61) - Phillips
LHA/LHD (LSD 44) - Fink, Sutherland
AOE (AOE-8) - Hertel
Review Syllabus:
Course objectives
Course resources (webpage, Textbook, Workbook)
Case studies - provide vivid and intriguing examples of the the fundamental principles taught in this course.
11/28/201811/28/2018

2. Lesson 20: Advanced Navigation Systems
AGENDA:
NAVSTAR Global Positioning System
Ship’s Inertial Navigation Systems (SINS)
Bottom Contour Navigation
LORAN-C
Electronic Charts (Raster & Vector)
Navigation Sensor System Interface (NAVSSI)
Applicable reading: Hobbs pp

3. NAVSTAR Global Positioning System (GPS)
GPS = Global Positioning System
A space based, all-weather, jam resistant, continuous operation, worldwide radio navigation system.
Provides extremely accurate 3D location data as well as velocity and time.
3 LOPs provide a Lat. & Long.
4 LOPs provide Lat., Long. & Altitude

7. NAVSTAR GPS Specifications
Frequency: 1227 MHz, 1575 MHz
Range: Worldwide
Accuracy: next slide
3 Types:
SPS- Standard Positioning Service
PPS-Precise Positioning Service
Differential GPS- for military only

8. NAVSTAR GPS Accuracy Standard Position Service (SPS)
Position: 100 m Hor m Vert.
Velocity: .5 m/sec
Time: 1 milli- second
Precise Position Service (PPS) - Military
Position: 16 m Hor. 25 m Vert.
Velocity: .1 m/sec
Time: 100 nano- seconds

9. NAVSTAR GPS Uses Civilian Uses Marine Navigation Law Enforcement
Hydrographic surveying
Search and Rescue
Collision avoidance
Military Uses
Marine Navigation
Air Navigation
Rendezvous
Close Air Support
Mine Warfare
Unmanned Aerial Vehicles (UAVs)

10. Differential GPS
A receiving station located at a fixed, known location receives fix information from GPS.
The fix obtained from GPS is compared to the known location of the station.
Any difference between these two is due to GPS error.

11. Differential GPS
GPS error information is then transmitted to vessels operating in the area.
The resulting fix accuracy is 2-5 meters using the differential technique
Requires more than 1 receiver

12. GPS Advantages Disadvantages Vulnerable to Attack
Continuous Coverage (regardless of weather)
worldwide coverage
3-D locator
Precise Timing Standard
Disadvantages
Vulnerable to Attack

13. Inertial Navigation Systems
Inertial Navigation: the process of directing the movements of a vessel based on sensed accelerations in known spatial directions.
System uses:
Gyroscopes
Accelerometers
Electronic computers

14. Inertial Navigation Systems
Current position is inputted Xo
Spinning gyro
Known mass
Accelerometer
F=m*a
Through Differentiation we get velocity and position (V and Xf)
Computer

15. Inertial Navigation Systems
Two types:
SINS (Ship’s Inertial Navigation System)
first used in 1960s
getting phased out
must be reset periodically
ESGN (Electrostatic Gyroscopic Navigation)
operates in a near perfect vacuum
rotor is solely supported by an electrostatic field
essentially frictionless
resets only required once every 30 days

16. Bottom Contour Navigation
Establishes position by using the geographic features of the ocean floor.
An echo sounder (fathometer) is used to produce a trace of the ocean floor beneath the vessel, which can be compared to a bottom contour chart to establish the ship’s position.

17. Bottom Contour Navigation
2 Techniques:
Line-of-Soundings (page 567 in Hobbs)
Contour Advancement (page 568 in Hobbs)

18. Bottom Contour Navigation
Advantages
no satelites required
subs=> no need to go to Periscope Depth (PD)
not vulnerable
Disadvantages
not very accurate
requires a cooperative sea bottom

19. LORAN (Long Range Navigation)
Over the years, many ground based electronic navigation systems were developed prior to satellite based systems becoming possible.
Most of these have been taken out of service, but LORAN still enjoys popularity and is still widely used.

20. LORAN (cont)
The operating principles of the system are similar to those now used by GPS.
Ground stations, at known locations, transmit signals at a predetermined time.
These signals are received by vessels at sea, and the time delay is used to form a range LOP.

21. LORAN (cont) First established in 1957.
Theory-hyperbolic LOPs based on time differences between master and secondary stations.
Run by the Coast Guard
Frequency: 100 kHz (LF)
Range: 1200 nm
Accuracy: yds

22. Electronic Charts Electronic Chart Display Systems (ECDS)
Raster Chart Display Systems (RCDS)

23. Navigation Sensor System Interface (NAVSSI)
Provides/Distributes NAV data (precise position, time, velocity, pitch-roll-yaw) to multiple users.
NAVSSI has been successfully installed, interfaced, and tested with WSN-5, WRN-6, EM Log, Tomahawk, Outboard, and NTCS-A.

25. Homework
Ch. 30
Section 1: 1
Section 2: 1, 5, 6, 9
Ch. 31
#4c, 5, 6