# Terms - VOR Indicator - CDI: course deviation indicator - RMI: Radio Magnetic Indicator - incorporates two bearing pointers, VOR and/or ADF, using selector switches - HSI: Horizontal Situation Indicator - Hash compass card - Course Selector POinter - Course Deviation Indicator - Dot = 2 degrees or 200 feet/nm - To/From Indicator - Heading Selector Knob - Course and Heading Set Knobs ## Intercepting a course - 30 degree intercept typical - CDI will show full scale deflection till you are within 10 degrees of course - Each dot 2 degrees - How fast the needle centers is how quickly you turn to selected course - 90 degree intercept is possible but start turning promptly - Tracking - Hit and miss - start with 20 and hold till needle centers - Then reduce to half and monitor drift - Keep halving VOR Cone of confusion - CDI and TO/FROM fluctuate as you arrive closer to station and over it, start turning early to intercept outgoing track VOR Service Volumes - see AIM VOR Line of sight VOR Checks 1. VOR Test Facilities +- 4 degrees 1. details 2. VOR Checkpoints 1. Ground +-4 degrees 2. Airborne +- 6 degrees 3. Dual System Check +- 4 degrees DME - slant range VOR DME Arcs - Twist 10 - Turn 10 - Use 10 to 20 degrees of wind correction ## Area Navigation (RNAV) - Can include - VOR / DME RNAV - INS (intertial navigation system) - GPS - WAAS certified under TSO-C145/C146 - Non-WAAS certified under TSO-C129/C196 - RNP - Required Navigation Performance - Nav equipment must be able to keep airplane within specific distance of the centerline of a route, path or procedure 95% of the time. - RNP 1.0 - Departure: within 1 nm of centerline on both sides - RNP 2.0 - Enroute - RNP 1.0 - Terminal - RNP 0.3 - Final Approach - Intertial Navigation System - Uses gyros, accelerometers and navigation computer to calculate position. - Exteremely accurate when set to a know position upon departure. - Without recalibration, INS accuracy degrades one to two nm per hour. - Automatically update based on inputs from VOR, DME, or GPS - Satellite Navigation (GPS) - Global Navigation Satellite System (GNSS) - standard term for satellite navigation systems - Global Positioning System (GPS) US version, globally available - Works via Trilateration - GPS satellites have atomic clocks - Radio wave signals from satellites travel at speed of light (186,000 miles per second) - Distance from satellite equals speed of light multiplied by signal travel time in seconds. - By calculating distance from 3 satellites simultaneously - you can determine position - Fourth satellite is needed for accuracy - adjusts the receiver clock error and calculates the receiver's correct position. - GPS guarantees accuracy to within 15 meters or less - WAAS (Wide area augmentation system) - Ground stations generate corrective message that is transmitted to the airplane by a geostationary satellite - Improves navigational accuracy by accounting for position drift of satellites and signal delays caused by ionosphere. - Before flight, must confirm WAAS is operational, GPS navigation equipment will not display approach procedures that require WAAS capability - Accurate to within 3 meters - GBAS (Ground based Augmentation System) - More accurate than WAAS. - Local receivers send corrections to airport ground facility that then transmits the corrections to receiver of VHF link - GBAS covers local area 20-30 miles around airport - Accurate to within 3 feet. - RAIM - For non-waas units - Continuously verifies the integrity of signals received from GPS constellation - For typical constellation - adds fifth satellite for integrity monitoring. Monitors the position provided by the other four satellites and alerts of any discrepancy - If RAIM is predicted to be unavailable, you must use other navigation equipment or delay or cancel flight ### GPS - Enroute full scale is 2 NM (Shown as ENR) on WAAS, 5 NM of non-WAAS - Terminal (within 30 nm of departure or destination airport) - full scale deviation equals 1 nm - Approach phase - inside final approach fix - full scale deviation equals 0.3 nm cross track error