1. VHF Omnidirectional Range (VOR)
Ground station oriented to magnetic north, transmitting directional information to aircraft
Benefits
More accurate, precise flying
Reliable
Not susceptible to interference
Voice Capable
Errors/Negatives
Costly to maintain
Line-of-sight

2. VOR Omnidirectional reference signal
Directional signal from antenna 1800 rpm
Receiver uses phase discrimination
Navigation in polar coordinates (rho-theta)
Distance Measuring Equipment (DME) & often Tacan are colocated with VOR

3. VOR Capabilities VHF – 108.0-117.95mhz 1 LOP at a time
Line of sight
1 LOP at a time
2 receivers give 2 LOPs (fix)
VOR + DME = LOP & Arc (fix)
Not sensitive to aircraft heading
Fly to or from a VOR or intercept a radial
Radial – courses oriented FROM the station

4. VOR Types High Low Terminal 1,000 – 14,500; 40NM
* All altitudes AGL

5. VOR Types

6. The Principle of the VOR
360
Magnetic North
045
315
135º
270
090
Didn’t Touch
135
225
180
VOR receiver gives 1 LOP called a Radial

7. Parts of a VOR system Receiver Course Deviation Indicator (CDI)
To/From ind.
CDI – needle that moves across the face of the instrument to indicate aircraft position. Each dot is 2 degrees.
OBS – allows pilot to select desired course/radial to fly
- must align with DG, otherwise reverse sensing
Ambiguity Indicator – indicates if selected course will take aircraft to or from the station
- station passage
- cone of confusion
Omni bearing selector

8. VHF Omnirange

9. VHF Omnirange
Which radial?

10. VHF Omnirange
Show the interception

11. Flying the VOR Initial Tracking Tune, Identify, Twist
Turn OBS to center needle and figure out position (use FROM)
Note heading on top of card
If flying FROM station (radial), then turn to that heading
If flying TO station, put reciprocal heading on top and center, then turn to that heading

12. Flying the VOR Wind Correction
Further away, more correction is needed to get back on track
At 60NM from station, 1° = 1NM
Generally, when within 20NM, 20-30° in direction of needle works
Once needle centers, turn back towards original heading, but add wind correction of 5°

13. Flying the VOR Station Passage Switching Radials
CDI will become very sensitive, and then begin to oscillate
Flag will switch from TO/OFF/FROM
Switching Radials
During station passage, turn OBS to new course to fly

14. Flying the VOR Intercepting
If needle is alive, then turn towards it as if you were tracking it
If full deflection, first center needle to find what radial you are on
Twist OBS back to desired course
Parallel that course
Turn in direction of needle, depending on distance from station
Once needle is alive, turn back in direction of desired course
Follow tracking procedures

15. Distance Measuring Equipment (DME)
Radio signal sent out from aircraft to ground station. Ground station interprets this signal and sends back. Equipment in aircraft measures time and converts to nautical miles.
Errors
Diagonal (slant-line) distance from station to aircraft – not lateral
Becomes greater the closer you get to the station
Greatest when directly over station at high altitudes
Limited number of queries
Uses
Intersections/Fixes
IAP
Groundspeed

16. Types of Navigation Systems
Pilotage
Dead Reckoning
Radio Navigation
ADF
VOR/DME/RNAV
Electronic Navigation
Loran
GPS
Inertial
Celestial
Types of Navigation:
-Electronic Navigation: The evolution of radionavigation to include satellite based systems such as SATNAV and GPS.

17. Area Navigation (RNAV)
Generic name for a system that permits point-to-point flight
Onboard computer that computes a position, track, and groundspeed
VOR/DME
Loran
GPS
Inertial

18. LOng RAnge Navigation (LORAN)
Collection of antennas throughout the United States transmit signals
Aircraft receiver calculates position based on intersection of multiple signals

19. 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.
Doesn’t this sound pretty neat, holy grail of navigation
Jam resistant, tell story about Iraqi GPS jammers and our GPS guided bombs

20. GPS System of 24 satellites, 4/5 of which are in view at all times
Receiver uses 4 of these to determine position of aircraft
Each satellite transmits code, which contains satellite position and GPS time
Receiver, knowing how fast signal was sent and at what time, calculates position

21. GPS Glossary RAIM – Receiver Autonomous Integrity Monitoring
Determines if satellites are providing correct data
WAAS – Wide Area Augmentation System
Collection of ground receivers take satellite data and correct it for atmospheric conditions
Works based on known position of ground stations
LAAS – Local Area Augmentation System
Same as WAAS, but on a smaller, more precise scale
For terminal area around airport

22. 12,000 miles above
Period = 12 hours

24. LOP – 1 Sphere Single range can lie anywhere on a sphere R1
Courtesy of Leica Geosystems

25. LOP – 2 Spheres
Two ranges will intersect on a line, defined by the intersection of two spheres
Courtesy of Leica Geosystems

26. LOP – 3 Spheres Three spheres intersect at a point
Three ranges needed to resolve lat/long/altitude
Notice that we said you need 4 before. The 4th is required to synchronize the receiver's clock
Courtesy of Leica Geosystems

27. GPS Uses Civilian Uses Marine Navigation Air Navigation Surveying
Search and Rescue
Collision avoidance
Agriculture
Military Uses
Marine Navigation
Air Navigation
Rendezvous
Close Air Support
Mine Warfare
Unmanned Aerial Vehicles (UAVs)

28. Inertial Navigation System
Dead-Reckoning
Self-contained source of:
Position, groundspeed, & heading
Does not even need a receiver
Cannot be jammed
Gets better with use
Applies a calibration correction after each flight

29. Primitive Accelerometer
No Acceleration
Acceleration M X
Acceleration from the right
F = kx = ma a = kx/m

30. Inertial Navigation Principles
Acceleration is vectorially summed in x, y, & z.
Output is compensated movement of the platform & for curvature & rotation of the earth.

31. Inertial Navigation Systems
Early systems required precise mechanical parts
Bigger is more accurate
Modern systems can be:
Mechanical (platform)
Simple gyros
Accurate
Electronic (strapdown)
Few moving parts
Smaller
Cheaper

32. Inertial Navigation Systems
Aircraft systems use
Pendulum accelerometers or MEMS
Micro-electromechanical sensors
Ring laser gyros
To measure angular change
INS complements GPS
Mechanical
Ring Laser Gyro

33. Types of Navigation Systems
Pilotage
Dead Reckoning
Radio Navigation
ADF
VOR/DME/RNAV
Electronic Navigation
Loran
GPS
Inertial
Celestial
Types of Navigation:
-Celestial Navigation: utilizes the known positions of celestial bodies (stars, planets, the sun and moon) relative to the earth to ascertain ship's position. Initially very mathematically intensive (3-D spherical trigonometry required) but it has now been reduced to tabulated information which is compared to actual observations to determine position.

34. Celestial Navigation Advantages No power required Self contained
Cannot be jammed
Available everywhere
Disadvantages
Dusk & dawn only
Clear weather only
Slow for aircraft
Needs the art of nav.
Navigator’s skill
Requires computation
At least data entry
Not on test at all

35. Circle of Equal Altitude
Charles Lindbergh used this during the night
Circle of Equal Altitude
DeRemer & McLean Global Navigation

36. Types of Errors Error increases with distance
VOR/DME, ADF
Error increases with time
DR, Inertial
Reliability Concerns
GPS, Loran, Celestial
Human error
Wise Old Owl

37. Which Types of Navigation are Important to a Student Pilot?
Pilotage
Dead Reckoning
Radio Navigation
ADF
VOR/DME/RNAV
Celestial
Electronic Navigation
Loran
GPS
Inertial

38. If Something Seems Wrong, it Probably is!
Be suspicious.
Check and recheck.
If you cannot tell your passengers your ETA at the destination, you are not navigating.
Navigation Philosophy

39. What can you do if you’re lost?
Assume you’re near your DR position
Do not assume a huge wind just came up
Use your VOR/DME or 2 VORs
Look on the chart for landmarks
Especially those that are shown small
If you miss a checkpoint, hold your heading & look for the next one
Do not guess where you are! If all else fails, CALL ATC (after all, YOU are paying for it)
Show what happens when you circle – get lost
2 VORs give you a fix