Lesson 14: Advanced Navigation Systems

1
Lesson 14 AdvancedNavigation Systems
2
Lesson 20 Advanced Navigation Systems

• AGENDA
• NAVSTAR Global Positioning System (GPS)
• Inertial Navigation Systems (INS)
• Bottom Contour Navigation
• Electronic Charts (Raster Vector)
• Navigation Sensor System Interface (NAVSSI)
• Applicable reading Hobbs pp. 540-555.

3
NAVSTAR Global Positioning System (GPS)

• GPS Global Positioning System
• all-weather, jam resistant, continuous operation,
  real-time, passive, worldwide radio navigation
  system.
• Provides
• Extremely accurate 3D position data
• Extremely accurate velocity data
• Precise timing services
• 3 LOPs provide a Lat. Long
• 4 LOPs provide Lat., Long. Altitude

4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
NAVSTAR GPS Uses

• Civilian Uses
• Marine Navigation
• Law Enforcement
• Hydrographic surveying
• Search and Rescue
• Collision avoidance

• Military Uses
• Rendezvous
• Close Air Support
• Mine Warfare
• Unmanned Aerial Vehicles (UAV/s)

WRN-6
8
WRN-6
9
Differential GPS (DGPS)

• A receiving station located at a fixed, known
  location receives position data from several GPS
  satellites.
• The data obtained from GPS is compared to the
  known location of the station.
• Any difference between these two is due to GPS
  error.
• This difference the applied to the individual GPS
  receiver and thus, increased positional accuracy
  is obtained

10
NAVSTAR GPS Accuracy

• Standard Position Service (SPS)
• Position 100 m Hor. 150 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

11
(No Transcript)
12
(No Transcript)
13
Inertial Navigation System (INS)

• Inertial Navigation the process of measuring
  the movements of a vessel based on sensed
  accelerations in known spatial directions.
• Gyroscopes
• Accelerometers
• Electronic computers

14
Inertial Navigation Systems (cont)

• Integrating acceleration gives you velocity
• Integrating velocity gives you position/distance
  traveled
• Need to compare to fix, since output is an EP!
• Can go up to 30 days w/out update, in theory
• Typically go no longer than 7-14 days
• Types
• SINS
• ESGN
• RLGN

15
Inertial Navigation Systems
Current position is inputted
Xo
Spinning gyro
Known mass
Accelerometer
Fma
Computer
Through Differentiation we get velocity and
position (V and Xf)
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 ships position.
• Can be used as a fix source, but is only accurate
  when large ocean floor gradients exist

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
• subsgt no need to go to Periscope Depth (PD)
• not vulnerable

• Disadvantages
• not very accurate
• requires a cooperative sea bottom

19
Electronic Charts

• Raster Chart Display Systems (RCDS)
• Electronic Chart Display Systems (ECDS)
• Not approved for Fleet use, but getting closer

20
(No Transcript)
21
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.
• A similar system may be integrated into your
  ships Combat Control System (CCS)

22
(No Transcript)
23
Summary/Review

• How does GPS work?
• What is ephemeris and almanac data?
• Name 3 uses of GPS.
• How does differential GPS work?
• How do Inertial Navigation Systems work?

24
QUESTIONS?