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Gps waas class 5 nov10

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The Global Positioning System (GPS) is a space-based radio-navigation system consisting of a constellation of satellites and a network of ground stations used for monitoring and control. …

The Global Positioning System (GPS) is a space-based radio-navigation system consisting of a constellation of satellites and a network of ground stations used for monitoring and control.
Minimum of 24 GPS satellites orbit the earth of which at least 5 are observable by a user anywhere on earth.
Minimum of 4 satellites is necessary to establish an accurate three-dimensional position.

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  • A FMS is a specialized computer system that automates a wide variety of in-flight tasks, reducing the workload on the flight crew. Using various sensors such as VOR, GPS and INS to determine the aircraft's position. The FMS can guide the aircraft along the desired flight plan. The FMS constantly crosschecks the various sensors and determines a single aircraft position and accuracy. The accuracy is described as the Actual Navigation Performance (ANP) a circle that the aircraft can be anywhere within measured as the diameter in nautical miles. Modern airspace has a set required navigation performance (RNP). The aircraft must have its ANP less than its RNP in order to operate in certain high-level airspace.
  • The Air Data Computer (ADC) provides the FMS with:
    True Air Speed (TAS)
    Barometric Altitude
    Pressure Altitude (PA)
    Indicated Airspeed (IAS)
    MACH Airspeed
    Static and Total Air Temperature
    All this is translated into useful information and displayed to the pilot as basic flight instruments and used by the FMS.
  • RNAV or Random navigation permits point to point navigation on any desired flight path within the coverage of station-referenced navigation aids or within the limits of the capability of self-contained aids, or a combination of these.
    We will see an increased dependence on RNAV with the FAA’s NextGen evolution from a ground-based system of air traffic control to a satellite-based system of air traffic management
  • Each GPS satellite transmits data that indicates its location and the current time. All GPS satellites synchronize operations so that these repeating signals are transmitted at the same instant. The signals, moving at the speed of light, arrive at a GPS receiver at slightly different times because some satellites are farther away than others. The distance to the GPS satellites can be determined by estimating the amount of time it takes for their signals to reach the receiver. When the receiver estimates the distance to at least four GPS satellites, it can calculate its position in three dimensions.
  • A GPS receiver "knows" the location of the satellites, because that information is included in satellite transmissions. By estimating how far away a satellite is, the receiver also "knows" it is located somewhere on the surface of an imaginary sphere centered at the satellite. It then determines the sizes of several spheres, one for each satellite. The receiver is located where these spheres intersect.
  • GNSS is the generic term for Air navigation utilizing GPS for Positioning, Navigation, and Timing (PNT) to enable performance-based RNAV operations for all phases of flight from en route, terminal, approach, and surface.
  • Receiver Autonomous Integrity Monitoring (RAIM) is a technology developed to assess the integrity of Global Positioning System (GPS) signals in a GPS receiver system. It is of special importance in safety-critical GPS applications. RAIM detects faults with redundant GPS pseudorange measurements. That is, when more satellites are available than needed to produce a position fix, the extra pseudoranges should all be consistent with the computed position. A pseudorange that differs significantly from the expected value (i.e., an outlier) may indicate a fault of the associated satellite or another signal integrity problem (e.g., ionospheric dispersion). Traditional RAIM uses fault detection (FD) only, however newer GPS receivers incorporate Fault Detection and Exclusion (FDE) which enables them to continue to operate in the presence of a GPS failure.
  • “RED FLAG”
    RAIM provides continuous fault detection and GPS signal integrity monitoring to determine if a satellite is providing corrupted information.
    Fault exclusion excludes a failed satellite from the position solution and is provided by WAAS receivers.
    Recheck RAIM Prediction for the destination during the flight. This may provide early indications that an unscheduled satellite outage has occurred since takeoff.
  • If a RAIM failure occurs after the Final Approach Way Point (FAWP), the receiver will continue operating without an annunciation for up to 5 minutes allowing completion of the approach (See AR-95-1).
    If a RAIM failure/status annunciation occurs prior to the Final Approach Waypoint (FAWP), the approach should not be completed since GPS may no longer provide the required accuracy.
  • Navigation databases are certified for en route and terminal operations contain, as a minimum, all airports, VORs, VORTACs, NDBs, and named waypoints (WPs) and intersections shown on en route and terminal area charts, SIDs, and STARs.
    Terminal area database include waypoints for SIDs and STARs, as well as other flight operations from the beginning of a departure to the en route structure or from an en route fix to the beginning of an approach procedure.
  • Determine that FMS published waypoints and transition names coincide with names found on the procedure charts and generally logical in location, in the correct order and that their orientation to each other is as found on the procedure chart, both laterally and vertically.
    GPS RNAV systems may use an algorithm, which applies the local magnetic variation and may produce small differences in the displayed course. However, both methods of navigation should produce the same desired ground track when using approved IFR navigation system.
    Should significant differences between the approach chart and the GPS database arise, the published approach chart, supplemented by NOTAMs, holds precedence.
  • GPS as with all navigation aids, interference, whether intentional or unintentional, is a concern. A number of methods for minimizing interference have been identified and tested and others are being investigated.
    The Wide Area Augmentation System (WAAS) helps to detect and mitigate these effects.   
  • Standard Positioning Service (SPS) – Accuracy within 100 meters lateral and 140 meters vertical and can be received by anyone with a GPS receiver.
    Precise Positioning Service (PPS) - Accuracy better than 7 meters horizontal with a probability of 95 percent. Precision data can be received only by authorized users (PPS) in possession of the proper cryptography.
  • The FMS computes and displays an estimate of position uncertainty (EPU) to advise the user of the system’s position accuracy. The estimate is the 95% probability that the FMS position is within a certain distance of the actual position. This is displayed on the FMS as Actual Navigation Performance (ANP) / Required Navigation
    Performance (RNP). ANP is a measure of the system’s best estimate of error, calculated to allow for flight technical error, in hundredths of a nautical mile. For example, if ANP = 1.00 nm, then there is roughly a 95% chance that
    the FMS position is within 0.91 nm of the actual position. The RNP value is the limit to position uncertainty the system will allow for continued flight and are specified for each phase of flight. RNP values are derived from three sources: manual entry, published database values, or FMS default values. The FMS default RNP values are determined by the phase of flight. Manually entered RNP values override published values, which override FMS default values. Refer to the table below for RNP priority, source and limits.
  • The FMS computes and displays an estimate of position uncertainty (EPU) to advise the user of the system’s position accuracy. The estimate is the 95% probability that the FMS position is within a certain distance of the actual position. This is displayed on the FMS as Actual Navigation Performance (ANP) / Required Navigation
    Performance (RNP). ANP is a measure of the system’s best estimate of error, calculated to allow for flight technical error, in hundredths of a nautical mile. For example, if ANP = 1.00 nm, then there is roughly a 95% chance that
    the FMS position is within 0.91 nm of the actual position. The RNP value is the limit to position uncertainty the system will allow for continued flight and are specified for each phase of flight. RNP values are derived from three sources: manual entry, published database values, or FMS default values. The FMS default RNP values are determined by the phase of flight. Manually entered RNP values override published values, which override FMS default values. Refer to the table below for RNP priority, source and limits.
  • Enroute – Greater that 30 miles from destination airport, GPS full scale CDI sensitivity equals +/- 5NM, or each GPS CDI dot equals 1.0NM linear deviation off course.
    Terminal – Within 30 miles from the airport, GPS CDI full scale sensitivity automatically changes to +/- 1NM, or each dot equals .2NM linear deviation mile off course.
    Approach - At two miles from the final approach waypoint (FAWP), GPS CDI full scale sensitivity automatically changes to +/- .3 NM, or each dot represents approximately 365 feet off course.
  • Satellite and ground-based equipment corrects and improves the accuracy of GPS receivers.
    North America – WAAS
    Asia - Multi-Functional Satellite Augmentation System (MSAS)
    Europe - Euro Geostationary Navigation Overlay Service (EGNOS)
    Eventually, GPS users around the world will have access to precise position data using an SBAS or other compatible system.
  • WAAS is North America’s Satellite Based Augmentation System (SBSA) that utilizes an additional two geostationary satellites positioned over North America that work in conjunction with 25 ground stations providing improved position accuracy and integrity to the base GNSS System.
    WAAS ground stations interpret existing GPS satellite constellation signals and make corrections to any errors that may exist.
    WAAS satellites repeat correction signals down to WAAS capable receivers.
    An additional sensor added to the FMS based on geostationary satellites.
    There are now more published LPV approaches than ILS approaches in the United States.
  • There are a few things that cause GPS not to be perfectly accurate. The charged particles of the ionosphere, and water vapor of the troposphere slow the signal slightly. Multipath, ephemeris errors, and the atomic clocks on the satellites themselves can also contribute to the inaccuracies.
    Throughout the continental U.S. are 25 "reference stations." These are GPS receivers that are placed at points that have been very accurately surveyed. These reference stations receive the same GPS signals as the moving receivers. The difference is instead of using the signal's travel time to calculate position, the reference stations use their known position to calculate timing. Because the reference stations know exactly where they are, they can figure out what the travel time of the signals should be. They then compare the calculated times with the actual times. The difference is an "error correction" factor.
    The error information is sent to two master stations (one on the U.S. east coast, one on the west coast) which calculate correction algorithms and assess the integrity of the system. A correction message is uplinked to the two WAAS satellites via a ground uplink system.
    The two satellites are in geostationary orbits. These satellites then transmit the correction information back down to the GPS user on the GPS frequency. The GPS receiver then decodes this information and applies it to its calculated position to significantly improve the accuracy.
  • WAAS hardware consists of 25 precisely surveyed Wide area ground Reference Stations (WRS) located around the U.S. , two wide area master ground stations (WMS), two geosynchronous communications satellites (GEO) and two transponder satellites.
  • The Wide Area Augmentation System or WAAS is a major improvement to GPS. A combination of 25 WAAS ground reference stations (WRS) monitor the GPS constellation signals and send corrections through two WAAS Master Stations (WMS) up to two geosynchronous satellites. These satellites then transmit the corrections to a WAAS enabled GPS receiver. More WRS are being installed in Alaska (4), Canada (4) and Mexico (5) to improve Northern Hemisphere coverage.
    WAAS provides several advantages. First, the geosynchronous satellites provide additional ranging signals into the WAAS enabled receiver, increasing GPS system coverage and availability. Since WAAS monitors and corrects variations in the GPS positioning, the system is much more accurate with smaller alert limits. This smaller integrity limit supports the current generation of GPS approaches, Localizer Performance with Vertical guidance (LPV).
  • Have the students watch the graphic. Tell them that the first circle shows the possible position error inherent in the normal GPS signal. Then click and show them how that position error drops to 7 meters with WAAS. (The rings are to the scale of the aircraft.)
  • The WAAS system was designed to the strictest of safety standards.
    Users are notified within six seconds of any issuance of hazardously misleading information that would cause an error in the GPS position estimate.
    Provides indications where system is unusable due to system errors or other effects.
    Precludes requirement for RAIM Monitoring
  • LNAV+V indicates that a descent angle is provided on procedures which have only LNAV minima, to aid in a stabilized descent, but the MDA must still be respected. With LNAV+V there is no vertical guidance provided for in FAA procedure design.  It is strictly a Jeppesen add on, and if done correctly, will not violate any step-down fixes in the final approach segment.  
  • LNAV/VNAV - Lateral Navigation with Vertical Navigation provides GPS LNAV along with a generated flight path in the vertical plane based on barometric altimetry or GPS WAAS. If WAAS is unavailable for vertical approach guidance, the aircraft must have a VNAV-capable Baro-Aiding input, which is typically a part of the flight management system (FMS).
    Localizer Performance with Vertical Guidance (LPV)
    A GPS approach associated with a WAAS system whereby the lateral component reacts like a localizer and the vertical component is provided by precise geometric WAAS vertical navigation. Due to smaller obstacle clearance requirements, LPV minimums will usually be lower than LNAV/VNAV or LNAV minimums.
  • Without WAAS or Baro-Aiding, GPS derived vertical navigation cannot be relied upon since the vertical error can be quite large (± 460 feet) and no integrity is provided.
    To ensure that baro-aiding is accurate, the current altimeter setting must be entered into the receiver as described in the operating manual.
    Baro-Aiding is a method of augmenting GPS lateral navigation with a vertical navigation solution computed by the FMS using a non satellite input source (Altimeter In-Put).
    Pilots must correct the descent path and DA/MDA for colder than standard temperatures.
  • FMS Temperature Compensation Pages: [FPL / MENU / TEMP COMP].
    Under conditions of extreme cold, barometric altimetry may be inaccurate, causing the actual aircraft altitude to be lower than that indicated by the altimeter. Some countries (e.g., Canada and Norway) have procedures defined whereby the pilot must refer to a table of information relative to landing airport elevation and temperature, and derive altitude corrections which are then added to charted approach altitudes.
    The FMS temperature compensation feature automates that process and relieves the pilot of this manual task.
  • Localizer performance with GPS vertical guidance.
    LPV approaches can only be accomplished with WAAS GPS receivers.
    LPV minimums as low as 200 feet AGL with required approach and runway lights.
    Has the potential to provide precision approach accuracy to almost all runways.
  • LP procedures require WAAS and are used at locations where the terrain or obstructions do not allow publication of vertically guided LPV procedures.
    LP approaches take advantage of the angular lateral guidance and smaller position errors. provided by WAAS to provide a lateral only procedure similar to an ILS Localizer.
    LP procedures may provide lower minima than a LNAV procedure due to the narrower obstacle clearance surface.
  • There are three possible Levels of Service that can be displayed: (1) LPV, (2) LNAV + VNAV, and (3) LNAV only.
    Examples of FMS LOS:
    • LPV: LPV is the highest (best) LOS provided by the FMS and is
    equated with the LPV line of minimums. LPV normally provides the
    lowest minimums available on an RNAV approach chart. If the FMS
    determines LPV level of service is available, the LPV LOS light will
    be illuminated.
    • LNAV + VNAV: LNAV + VNAV is the second highest LOS possible
    and is equated with the LNAV/VNAV line minimums on the approach
    chart. If the FMS determines LNAV + VNAV level of service is
    available, both the LNAV and the VNAV Level of Service lights will
    be illuminated.
    • LNAV: LNAV is the lowest LOS and is equated with the LNAV line of
    minimums on the approach chart. If the FMS determines only LNAV
    level of service is available, the LNAV Level of Service light will be
    illuminated.
    Upon arrival at the alternate airport, the approach may be flown to the best (lowest) minimums available, including LPV and LNAV/VNAV.
  • Any WAAS RNAV approach with LPV minimums will be identified in the database by a W located to the left
    of the selection number. In the figure below depicting the available approaches at GEG, notice the RNAV approaches to runways 07 and 25 are WAAS approaches as indicated by the W. Both of these approaches have LPV minimums. All of the other approaches listed below do not require WAAS and do not have LPV minimums.
  • When the approach is armed, the predicted Level Of Service (LOS) is presented in the upper right corner of NAV pages 1 & 2. If the LOS changes prior to approach activation, at activation the MS will change the LOS and push a message indicates a of LOS. The pilot may manually downgrade the LOS on the RNAV APPR LOS page by way of the APPR LOS line select key. A selection of a new LOS must be accomplished prior to the FAF. After sequencing of the FAF, LOS cannot be changed.
  • LNAV is a non-precision GPS approach without vertical guidance and is flown down to a Minimum Descent Altitude (MDA).LNAV/VNAV procedures are flown with vertical guidance using either WAAS or barometric (Baro-Aiding) vertical navigation and flown down to a Decision Altitude (DA).
    LNAV/VNAV provides vertical guidance, but may not meet the more stringent standards of a precision approach depending on the Level OF Service (LOS) available.
    WAAS receivers are able to fly LNAV/VNAV procedures using a WAAS electronic glide path, which eliminates the errors that can be introduced by using Bar-Aiding.The LPV approach has vertical guidance and is flown down to a Decision Altitude (DA). The LPV typically has lower minimums than the LNAV/VNAV because the Required Navigation Performance (RNP) decreases as you get closer to the MAP (much like a localizer).
    LNAV/VNAV usually has higher minimums than the LPV because when designing the approach, the designers look further from the approach course for obstacles.
    How do you determine if LNAV/VNAV or LPV minima apply? The answer is the Level of Service (LOS) that is currently available and annunciated to the pilot as LPV LNAV/VNAV, or LNAV.
    For example, if WAAS is not available, but Baro-Aiding is available and annunciated to the pilot as LOS - LNAV/ VNAV, then the LNAV/VNAV minima apply.
  • The first authorization for using GPS to fly approach procedures was known as GPS overlays. These procedures authorized use of approved GPS receivers to fly existing non-precision instrument approaches. The only difference was that course guidance could come from the GPS system. These procedures are identified with "or GPS" in the title. The advantage for these procedures was twofold. First, overlay approaches provide the aviator greater position awareness than that derived from using the ground NAVAID. Second, although they didn't provide lower minima, GPS overlays also introduced and validated GPS approaches to aviation. This initial validation was critical for future GPS improvements.
    The GNSS Landing System (GLS) decision altitude was a place holder for ongoing upgrades to WAAS and for LAAS. It has been replaced by LPV on the RNAV(GPS) charts. The acronym GLS is now associated with the LAAS minima and will be published on a separate chart when LAAS approaches become available.
    The FMS will fly all approach transitions up to the FAF, but prior to that point the pilot should transition the
    navigation source and FGS mode to ILS guidance.
  • Notice that the plate on the left does not follow the standard T format. Also notice that there is no TAA depicted (only MSA). As such, you can only descend prior to the IAF if you are established on one of the two transition routes (from PDZ or ACINS).
    The IAP on the right is in the standard T format and has a TAA depicted (the MSA quadrants are broken apart and are based upon the IAF(s)). In this case, once cleared for the approach (and ATC does not tell you to maintain an altitude), you are cleared to descend once inside the TAA (inside 30 nm of the IAF that the TAA sector is based upon).
  • Only applicable to R-NAV Approaches
    Not published for all RNAV Approaches (especially in busy areas)
    Replaces MSA but still gives 1,000’ obstacle clearance (or more if necessary in mountainous areas)
    Transition to TAA automatically if entering it from a Transition Route or Airway (unless cleared otherwise)
    “Pilots entering the TAA and cleared by ATC, are expected to proceed directly to the IAF associated with that area of the TAA at the altitude depicted, unless otherwise cleared by ATC.” AIM 5-4-5
    IAPs with a TAA depiction are the ONLY approaches that you can descend on before being established on a segment of the approach. The TAA is unique compared to all other IAP procedures in that one can NOT descend (even on an RNAV IAP) based upon an MSA / ESA alone.
  • Only applicable to R-NAV Approaches
    Not published for all RNAV Approaches (especially in busy areas)
    Replaces MSA but still gives 1,000’ obstacle clearance (or more if necessary in mountainous areas)
    Transition to TAA automatically if entering it from a Transition Route or Airway (unless cleared otherwise)
    “Pilots entering the TAA and cleared by ATC, are expected to proceed directly to the IAF associated with that area of the TAA at the altitude depicted, unless otherwise cleared by ATC.” AIM 5-4-5
    IAPs with a TAA depiction are the ONLY approaches that you can descend on before being established on a segment of the approach. IAPs other than a TAA, one can NOT descend (even on an RNAV IAP) based upon an MSA / ESA alone.
  • LAAS, the GPS-corrected navigation signal is broadcast from a LAAS VHF data broadcast transmitter at or near the airport. The Local Area Augmentation System (LAAS) will augment the GPS and complement WAAS by providing an all-weather approach, landing, and surface navigation capability. It is expected that the end-state configuration will pinpoint the aircraft's position to within one meter or less. Curved approach paths, not possible using the current instrument landing systems, will be possible for Category I, II, and III precision approaches as the system evolves. Increased accuracy will allow more arrival and departure procedures. Approaches will be designed to avoid obstacles, restricted airspace, noise sensitive areas, or congested airspace. Similar to WAAS, LAAS works by monitoring the GPS signal, but in the case of LAAS, sends corrections directly to the aircraft. This not only provides greater integrity but also much quicker alerting.
  • LAAS is a Ground-Based Augmentation System. The Local Area Augmentation System (LAAS) is an all-weather aircraft landing system based on real-time differential correction of the GPS signal. Local reference receivers located around the airport send data to a central location at the airport. This data is used to formulate a correction message, which is then transmitted to users via a VHF Data Link. A receiver on an aircraft uses this information to correct GPS signals, which then provides a standard ILS-style display to use while flying a precision approach. The International Civil Aviation Organization (ICAO) calls this type of system a Ground Based Augmentation System (GBAS).
  • The Joint Precision Approach and Landing System (JPALS) is a military, all-weather landing system based on real-time differential correction of the GPS signal, augmented with a local area correction message, and transmitted to the user via secure means. The onboard receiver compares the current GPS-derived position with the local correction signal, deriving a highly accurate three-dimensional position capable of being used for all-weather approaches via an ILS-style display. While JPALS is similar to Local Area Augmentation System, but intended primarily for use by the military
  • Straight-in approaches are uniquely defined by geographic coordinates of runway thresholds, glide path angle, and threshold crossing height.
  • Transcript

    • 1. Global Positioning Systems (GPS/WAAS)
    • 2. Terminal Learning Objective Action: Identify capabilities and functions of a Flight Management System (FMS) with the Global Positioning System (GPS/WAAS). Condition: In a classroom or in the aircraft and without reference for the written exam. Standard: IAW the Guardrail student evaluation plan.
    • 3. Administrative Data SAFETY REQUIREMENTS: NONE RISK ASSESSMENT LEVEL: IV/E – Low ENVIRONMENTAL CONSIDERATIONS: No Impact. Evaluation: This material may be evaluated in the Phase II/III Flight Evaluation. Classification: Unclassified.
    • 4. Agenda • • • • • • FMS Terms FMS Inputs Global positioning System (GPS) Wide Area Augmentation System (WAAS) GPS Instrument Approaches AR 95-1 Compliance
    • 5. REFERENCES • FM 2-04.240 (FM 1-240), Chapter 7 • AIM, Section 1-1-19 • FAA-H-8261-1A, Instrument Procedures Handbook, Chapter 5 and 6 • AR-95-1, Chapter 5 • SEMA Hand - Out, GPS RNAV And Approach Charts • SEMA Hand – Out, RC-12X Flight Management System Universal SCN 1100 Operator’s Manual
    • 6. Flight Management System (FMS) Automates a wide variety of in-flight tasks: • Aircraft performance and flight plan management. • Computes aircraft position using multiple aircraft sensors (VOR,GPS, INS). • Contains navigation database. • Provides performance and flight path guidance information to pilot navigation displays and automatic flight control systems
    • 7. FMS INPUTS Navigation Inputs from each "active" sensor are blended or deselected then summed up to provide the best possible position data.
    • 8. FMS Sensor Inputs • • • • • • • ADC (Air Data Computer) DME/DME VOR GPS / WAAS IRU / INS (Inertial Reference System) Fuel Flow Barometric Altitude
    • 9. Common GPS/FMS Terms ADC – Air Data Computer GPS - Global Positioning System IRU – Inertial reference Unit INS – Inertial Navigation System EGI - LN-100 Inertial Navigation System with embedded Global Positioning System (GPS) RNAV - Area Navigation GNSS - Global Navigation Satellite System SBAS - Satellite Based Augmentation System. A general term for WASS navigation GLS - GNSS Landing System ( LPV and LAAS Approaches) WAAS - Wide Area Augmentation System LNAV - Lateral Navigation (GPS/WAAS) LNAV+V - LNAV approach where an advisory only descent angle is provided APV - Approach with Vertical Guidance LNAV / VNAV– GPS/WAAS Lateral Navigation with WAAS or Barometric Vertical Guidance LPV - GPS/WAAS Localizer Performance with GPS Vertical Guidance GLS - GNSS Landing System ( LPV and LAAS Approaches) RAIM - Receiver Autonomous Integrity Monitoring ANP – Actual navigation Performance RNP – Required Navigation Performance
    • 10. Inertial Navigation System (INS) • INS uses a computer and motion sensors (accelerometers) mounted on gyro-stabilized, gimbaled platforms to continuously calculate velocity and dead reckoning position without the need for external references. • INS gyros can also provide aircraft attitude (pitch, roll, and heading). • Once aligned with a known position, INS continuously calculate position and velocity. • INS position accuracy decays with time.
    • 11. Air Data Computer (ADC) The Air Data Computer (ADC) provides the FMS with: • True Air Speed (TAS) • Barometric Altitude • Pressure Altitude (PA) • Indicated Airspeed (IAS) • MACH Airspeed • Static and Total Air Temperature All this is translated into useful information and displayed to the pilot as basic flight instruments and used by the FMS.
    • 12. Student Check Q: An Inertial Navigation System (INS) requires external navigational aids to operate. True or False? • A: FALSE, INS uses a computer and motion sensors (accelerometers) mounted on gyrostabilized, gimbaled platforms to continuously calculate velocity and dead reckoning position without the need for external references.
    • 13. Embedded Global positioning system / Inertial Navigation System (EGI) • LN 100 is an INS system incorporating an imbedded GPS that is a component of the RC-12X’s mission equipment. • INS alone without up-dating, errors are cumulative and increase with time (about .6NM per hour error). • GPS greatly enhances the performance of an INS by providing an in-flight position up-date capability for the INS. • When GPS is not available because of mountain shadowing of satellites or jamming, INS provides accurate position information until the GPS satellites are in view or the jamming is over.
    • 14. Area Navigation (RNAV) • Permits point to point navigation. • We will see an increased dependence on RNAV with the FAA’s NextGen evolution.
    • 15. ADS-B • Automatic Dependent Surveillance Broadcast (ADS-B – Evolving system that utilizes aircraft transponders and GPS signals to display an aircraft’s precise position combined with other data and broadcast to other aircraft and air traffic controllers without ground based radar. • ADS-B may eventually replace ground based ACT radar.
    • 16. Global Positioning System (GPS) • GPS is a space-based radio-navigation system consisting of a constellation of satellites and a network of ground stations used for monitoring and control. • Minimum of 24 GPS satellites orbit the earth of which at least 5 are observable by a user anywhere on earth. • Minimum of 4 satellites is necessary to establish an accurate three-dimensional position.
    • 17. 24 Satellites, a minimum of 4 is required.
    • 18. GPS Coverage Accurate three-dimensional navigation is available to an infinite number of GPS receivers anywhere on or near the Earth within Line of Sight to GPS satellites.
    • 19. How GPS Works
    • 20. Global Navigation Satellite Systems GNSS The generic term for air navigation utilizing GPS for RNAV operations for all phases of flight from departure, enroute, terminal, approach, and surface.
    • 21. Receiver Autonomous Integrity Monitoring (RAIM) • The RAIM system monitors the status of GPS satellites and broadcasts the GPS status as part of data message transmitted by GPS satellites. • GPS status information is available by the Notice to Airmen (NOTAM) system. • RAIM Prediction
    • 22. In-Flight (RAIM) • Continuous fault detection • Excludes a failed satellites from the FMS position solution. • RAIM Prediction in flight provides early indications of unscheduled satellite outage that has occurred since takeoff. • WAAS availability precludes In-Flight RAIM.
    • 23. RAIM FAILURE • If a RAIM failure occurs after the Final Approach Way Point (FAWP), the receiver will continue operating without an annunciation for up to 5 minutes allowing completion of the approach (See AR-95-1). • If a RAIM failure/status annunciation occurs prior to the Final Approach Waypoint (FAWP), the approach should not be completed since GPS may no longer provide the required accuracy.
    • 24. Standard GPS Accuracy Basic GPS signal (worst case scenario) – • Approximately 100 meters (328 ft) lateral FAA-H-8083-15A • Approximately 140 meters (460 ft) vertical Pg 7-27 www.faa.gov 460 ft 328 ft
    • 25. FMS Navigation Databases • Navigation databases certified for en route and terminal operations are loaded into the FMS. • Contain airports, VORs, VORTACs, NDBs, airways and named waypoints (WPs), intersections shown on en route charts, instrument approach charts, SIDs, and STARs. • There is no specific requirement to check the latitude and longitude of each published database waypoint, type of waypoint and/or altitude constraint. Verify only the general relationship of waypoints in the procedure, or the logic of an individual waypoint's location.
    • 26. Use of GPS for IFR Oceanic, Domestic En  Route, and Terminal Area Operations • GPS procedures may be restricted outside the United States. Check for restrictions in FLIP GP and area planning (AP) documents. • GPS procedures for IFR navigation in the terminal area, equipment must include an updatable navigation database. • GPS airborne navigation databases may come from the National Geospatial Agency (NGA) or from an approved commercial source such a Jeppessen.
    • 27. GPS Satellite Jamming and Interference • GPS as with all navigation aids, interference, whether intentional or unintentional, is a concern. A number of methods for minimizing interference have been identified and tested and others are being investigated. • The Wide Area Augmentation System (WAAS) helps to detect and mitigate these effects.
    • 28. ANTI-SPOOFING • SELECTIVE AVAILABILITY (SA) - Used to deny hostile use of precise GPS positioning data. • SA is implemented by DoD to intentionally degrade a non DoD user’s navigation solution resulting in a five-fold increase in positioning error. • Selective Availability was discontinued in May 2000 but could be re-activated.
    • 29. Levels of Accuracy Available • Standard Positioning Service (SPS) – Accuracy is 100 meters lateral and 140 meters vertical and can be received by anyone with a GPS receiver. • Precise Positioning Service (PPS) - Accuracy better than 7 meters horizontal. Available to PPS users in possession of proper cryptography.
    • 30. Actual Navigation Performance (ANP) • ANP is a measure of the system’s best estimate of error, calculated to allow for flight technical error. • ANP = 1.00 nm, means a 95% chance that the FMS position is within 1.00 nm of the actual position.
    • 31. Required Navigation Performance (RNP) • RNP is a statement of navigation performance necessary for operation within a defined airspace. • RNP navigation requires inputs from GPS and/or WAAS to calculate the precision "corridor" or "highway" of an RNP procedure. • Maintaining a narrow "RNP" corridor of flight space in both vertical and lateral planes allows for increased aircraft operations for any given period of time. • Flight Management Systems are used to navigate RNP procedures with RNP procedures in their databases. • Standard GPS approaches require at least .3 nautical mile RNP accuracy on final approach, however, some RNP approaches require greater than .3NM accuracy on final approach. • FAA requires specialized aircrew training requirements for RNP GPS instrument approaches.
    • 32. Standard RNP
    • 33. Radius -TO-Fix leg “RF” RNP 0.11
    • 34. GPS Course Deviation Indicator (CDI) Scaling • Enroute – Greater that 30 miles from destination airport, GPS full scale CDI sensitivity equals +/- 5NM, or each GPS CDI dot equals 1.0NM linear deviation off course. • Terminal – Within 30 miles from the airport, GPS CDI full scale sensitivity automatically changes to +/- 1NM, or each dot equals .2NM linear deviation mile off course. • Approach - At two miles from the final approach waypoint (FAWP), GPS CDI full scale sensitivity automatically changes to +/- .3 NM, or each dot represents approximately 365 feet off course.
    • 35. RNP Navigation
    • 36. Student Check Q: Standard GPS Final approaches require accuracy of at least a. .1 nautical mile accuracy. b .5 nautical mile accuracy. c. .3 nautical mile accuracy. A: c. .3 nautical mile accuracy.
    • 37. Satellite Based Augmentation Systems (SBAS) SBAS systems correct and improves the accuracy of GPS receivers. • North America – WAAS • Asia - Multi-Functional Satellite Augmentation System (MSAS) • Europe - Euro Geostationary Navigation Overlay Service (EGNOS) Eventually, GPS users around the world will have access to precise position data using an SBAS or other compatible system.
    • 38. Wide Area Augmentation System (WAAS) • North America’s Satellite Based Augmentation System (SBSA) utilizes an additional two geostationary satellites that work in conjunction with 25 ground stations, providing improved position accuracy and integrity to the base GNSS System. • WAAS ground stations interpret existing GPS satellite constellation signals and make corrections to any errors that may exist. • WAAS satellites repeat correction signals down to WAAS capable receivers. • An additional sensor added to the FMS based on geostationary satellites. • There are now more published LPV approaches than ILS approaches in the United States.
    • 39. How WAAS Works
    • 40. WAAS STATIONS
    • 41. Benefits of SBAS/WAAS • ILS-like approach procedures (LPV). •Higher level of service and accuracy. •An electronic glide path can be generated independent of ground equipment or barometric aiding. •Key benefit - Vertically-Guided Instrument Approach minimums as low as 200 feet AGL.
    • 42. WAAS ACCURACY WAAS improves GPS signal accuracy from 100 meters (328 ft) to approximately 7 meters (23ft). www.faa.gov
    • 43. WAAS - Safeguards • WAAS system is designed to strictest of safety standards. • Users are notified within six seconds of any of hazardous or misleading information that would cause an error in the GPS position estimate. • Provides indications where system is unusable. • Precludes In-Flight RAIM Monitoring
    • 44. LNAV Instrument Approaches • LNAV is a Non-Precision Approach when Lateral Navigation only is provided by GPS and/or WAAS. • The pilot flies the final approach with Lateral Navigation provided by GPS, however, the pilot is responsible for vertical navigation. • The pilot descends to step-down altitudes and to the Minimum Descent Altitude (MDA) referencing the pilot’s barometric altimeter. • LNAV+V - When an Advisory Only Descent Angle is provided.
    • 45. GPS Approaches With Vertical Guidance • LNAV/VNAV - When Lateral along with Vertical Navigation is provided. The LNAV is provided by GPS and the VNAV is provided by either WAAS or an FMS Barometric Aided VNAV computation (Baro-Aiding). • Localizer Performance with Vertical Guidance (LPV) When WAAS is required for both Lateral and Vertical navigation. LPV minimums will usually be lower than LNAV/VNAV or LNAV minimums.
    • 46. Baro-Aiding VNAV • Without WAAS or Baro-Aiding, the GPS derived vertical navigation cannot be relied upon since the vertical error can be quite large (± 460 feet) and no integrity is provided. • Baro-Aiding is a method of augmenting GPS lateral navigation with a vertical navigation solution computed by the FMS using a non satellite input source (Altimeter In-Put). • To ensure that Baro-Biding is accurate, the current altimeter setting must be entered. • Pilots must correct the descent path and DA/MDA for colder than standard temperatures.
    • 47. Baro-Aiding Temperature Compensation
    • 48. LPV Approach - Localizer Performance with Vertical Guidance • Localizer performance with GPS vertical guidance. • LPV approaches can only be accomplished with WAAS GPS receivers. • LPV minimums may be as low as 200 feet AGL with required approach and runway lights. • Has the potential to provide precision approach accuracy to almost all runways.
    • 49. Localizer Performance Approaches (LP) • LP procedures require WAAS for later guidance only. • Used at locations where the terrain or obstructions do not allow publication of vertically guided LPV procedures. • LP approaches take advantage of the angular lateral guidance and smaller position errors. provided by WAAS to provide a lateral only procedure similar to an ILS Localizer. • LP procedures may provide lower minima than a LNAV procedure due to the narrower obstacle clearance surface.
    • 50. Level of Service Lights (FMS LOS) • LOS is based on predicted GPS horizontal and vertical accuracy against required horizontal and vertical approach limits. • LPV - Highest LOS provided by the FMS, equated with LPV approach minimums. When the FMS determines that LPV LOS is available, the LPV LOS light will be illuminated. • LNAV + VNAV - Second highest LOS . When the FMS determines LNAV + VNAV level of service is available, the LNAV + VNAV Level of Service light will be illuminated. • LNAV - Lowest LOS. When the FMS determines that only LNAV level of service is available, the LNAV Level of Service light will be illuminated. NOTE: LPV approach operations require two operational FMS.
    • 51. WAAS LPV Approaches Identified by a “W”
    • 52. Level Of Service
    • 53. Standard Format for RNAV/GPS Minimums Approach minima (LPV, LNAV/VNAV, LNAV) is predicated on Level Of Service (LOS) annunciated.
    • 54. GPS Approach Procedures • • Stand-Alone - Procedures are designed for use only by GPS systems. GPS overlay – GPS procedure overlaid on conventional VOR, VOR/DME, etc. procedures. Are titled with the type of Navigational Aid (NAVAID), including "or GPS" (e.g., VOR or GPS RWY 24). • Approaches that may be flown in the GPS mode will contain “RNAV” or "GPS" in the title (e.g., "VOR or GPS RWY 24," "GPS RWY 24," or "RNAV (GPS) RWY 24"). • When flying overlay GPS approaches, the underlying ground-based NAVAIDs are not required to be operational and associated aircraft avionics need not be installed and/or operational. • ILS Approaches – The ILS approach transition and published missed approach segments may be flown in the FMS mode, however, the ILS final approach segment must be flown with the LOC navigation source selected.
    • 55. Flying GPS Approaches • • • • • Fly the full approach from an Initial Approach Waypoint (IAWP) or feeder fix unless specifically cleared otherwise. When receiving vectors to final, place the FMS in the no-sequencing mode (Activate Approach) and use Command Heading. An "arm" annunciation should occur 30 NM straight line distance from the end of the runway reference point and then it should arm automatically. Without arming, the receiver will not change from en route CDI and RAIM sensitivity of ±2 NM either side of centerline to ±1 NM terminal sensitivity. Within 2 NM of the FAP with the approach mode armed, the approach mode will switch to active, which results in changing to approach CDI sensitivity of ±0.3 NM at the FAWP.
    • 56. GPS Approach Formats Standard “I” Standard “T”
    • 57. Terminal Arrival Area (TAA)
    • 58. Terminal Arrival Area (TAA) Right Base Left Base Straight-In
    • 59. Terminal Arrival Area (TAA) Right Base Left Base Straight-In
    • 60. Fly-By Waypoint Fly-Over Waypoint
    • 61. GPS Missed Approach • Pressing the Go-Around button will automatically sequence the FMS to the missed approach segment of the procedure past the Missed Approach Way Point (MAWP). • Turns should not begin prior to the MAWP.
    • 62. Local Area Augmentation System (LAAS) • LAAS provides a GPS corrected navigation signal that is broadcast from a LAAS VHF data broadcast transmitter at or near some airports. • LAAS avionics must be installed on aircraft. • LAAS covers approximately a 30-mile radius and provides up to Category III precision approach minimums (DA 50 feet) with accuracy within 1 Meter.
    • 63. Local Area Augmentation System (LAAS) LAAS improves GPS signal accuracy from 100 meters (328ft.) to approximately 1 meter (3ft.).
    • 64. How LAAS Works
    • 65. JPALS Joint Precision Approach and Landing System • Mobile, LAAS-like DoD system • All-weather, all-mission, all-user landing system based on local area Differential Global Positioning System (DGPS). • Provides accurate and reliable landing guidance for fixed and rotary wing aircraft during all weather conditions.
    • 66. JPALS • Features a high GPS anti-jam protection to assure mission continuity in a hostile environment • Compatible with civil and military GPS signals
    • 67. AR 95-1 Chapter 5 Flight Procedures and Rules GPS is authorized for IFR flight if— • IFR GPS is authorized in the applicable sovereign airspace- check DOD FLIP Area Planning (AP). • Installed GPS equipment is certified for IFR operation. • Precise Positioning Service (PPS) will be operated in the PPS mode. • Current DOD/US Government FLIP products will be carried and accessible at all times.
    • 68. AR 95-1 User Defined Waypoints • IFR RNAV/GPS departure, arrival, en route and terminal procedures will only be flown using waypoints retrieved from an approved non-corruptible database. • Manual entry or update of the navigation database other than storing “user defined data” is not authorized (except for approved EMER GPS procedures).
    • 69. AR 95-1 Approved Databases – • Use of commercial IFR databases (for example, Jeppessen) in Army aircraft is only authorized in the United States and US territories. • Use of commercial databases elsewhere in the world is restricted to en route navigation or to US military facilities overseas unless approved by USAASA/USAASD–E.
    • 70. AR 95-1 IFR Alternate Selection – An airfield will not be selected as an alternate If the global positioning system (GPS) is required for the approach and descent from en route minimum altitude for IFR operation, approach, and landing cannot be made in VFR conditions..
    • 71. AR 95-1 Prior to IFR GPS Flight Check— • All required navigation performance (RNP) levels must be met when operating in designated RNP airspace. • IFR GPS flight will not be conducted with an expired navigational database. • Appropriate suffix for GPS/RNAV equipment will be entered on the flight plan, e.g.: “G” for DD 175 or “S / ITG /S” for DD 1801. NOTE: Flight Plans Requesting “Q” or “T” Routes”, RNAV SIDs and STARs require filing in the ICAO Flight plan format.
    • 72. AR 95-1 GPS Substitution of Navigation aids– When operating IFR in the US National Airspace System (NAS), GPS waypoints may be used as substitutes for ADF and/or DME receivers. Consult DOD FLIP/host nation for authorized substitutions.
    • 73. AR 95-1 RNAV/GPS Departure Procedures (DP)• (DP) must have terminal RAIM availability prior to departure. • The CDI sensitivity will be set to + or - 1nm sensitivity or as published.
    • 74. AR 95-1 GPS approach Requirements : • • • • • When using a Digital Aeronautical Flight Information File (DAFIF) database, terminal procedures authorized to be flown are RNAV/GPS procedures and GPS overlay approaches if the title contains “or GPS” and the procedure has a Final Approach Fix (FAF) and the procedure can be retrieved from the database. Underlying NAVAIDS on overlay approaches should be tuned and monitored during the approach. DAFIF will not be used in Flight Management Systems (FMS) to drive/sequence other conventional NAVAID terminal procedures, for example, NDB, VOR, TACAN. Same approach must be reviewed and displayed to the crew from the current DOD FLIP procedure. Compare the database retrieved procedure loaded in the GPS to the published procedure to ensure accuracy, If differences are detected, the published product, supplemented by NOTAMs, will take precedence over the database procedure.
    • 75. AR 95-1 GPS Approach Procedures • Verify the GPS system begins to sequence when entering the terminal area, that the approach is armed prior to the Initial Approach Fix (IAF) and that course sensitivity on the CDI changes appropriately. • If a RAIM failure/status annunciation occurs or the GPS does not sequence to the “active approach” mode, the pilot will request an alternate procedure or if already passed the Final Approach Waypoint (FAWP), the pilot will climb to the missed approach altitude and execute the missed approach.
    • 76. AR 95-1 GPS Approach Minimums • Approach minimums listed as GLS (or LPV), and LNAV/VNAV, categories will only be flown if the aircraft is appropriately equipped. • Barometric Vertical Navigation (baro-VNAV) decision altitude (DA) is not authorized with a remote altimeter setting. If local altimeter setting is not available, the MDA becomes the published LNAV MDA, cold temperature restrictions apply. • Circling from RNAV/GPS approaches may be accomplished if circling minimums are published.
    • 77. AR 95-1 GPS Missed Approach Upon missed approach, pilots will ensure the missed approach function has been appropriately activated on the GPS.
    • 78. Student Check Q: An IFR alternate airfield may be selected if the global positioning system (GPS) is required for an IFR approach to that airfield and descent from en route minimum altitude for IFR operation, approach, and landing cannot be made in VFR conditions.. True or False? A: FALSE
    • 79. Summary • • • • • • FMS Terms FMS Inputs Global positioning System (GPS) Wide Area Augmentation System (WAAS) GPS Approaches AR 95-1 Compliance
    • 80. Questions ?

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