The Aircraft inability to achieve the required lateral navigation accuracy may be due to navigation errors related to Aircraft tracking and positioning. The main errors in the context of on-board performance monitoring and alerting are:
Path definition error (PDE), flight technical error (FTE), navigation system error (NSE) and total system error (TSE).
Path definition error (PDE) and navigation system error (NSE) only , due to Flight technical error (FTE) relates to the air crew or autopilot’s ability to follow the defined path or track and it not taking into account for Total system error (TSE) computation
The performance-based navigation (PBN) concept specifies that aircraft RNAV system performance requirements be defined in terms of:
accuracy, integrity, availability, continuity and functionality required for the proposed operations in the context of a particular airspace concept.
accuracy, integrity, continuity, passenger comfort and functionality required for the proposed operations in the context of a particular airspace concept.
Type of sensors feeding the navigation computer
Navigation Infrastructures Defined in certain Airspace
Two main purposes of ATC are to:
Protect the sovereign airspace against threats
Define training procedures and materials for air traffic controllers.
Steer an aircraft in flight from an initial position to a final position safely and efficiently.
Ensure a proper separation of air traffic in all phases of flight, while providing for the highest efficiency in aircraft operations both in ground and in flight, in order to reduce delays and optimize the use of the airspace.
Prevent collisions.
Expediting and maintaining an orderly flow of air traffic.
In class A aerospace:
No ATC service is provided.
All flights are provided with ATC services and aircraft separation.
IFR flights only are permitted, all flights are provided with air traffic control service and are separated from each other
No speed limitation is imposed.
Continuous two way communications are required.
Is subject to ATC clearance.
The standard terminal arrival, STAR, is an aeronautical chart that:
Applies to uncontrolled airspace.
Does not include holding patterns.
Defines the procedure to be followed to join an airway after take-off.
Defines the flight procedures to be followed by the pilot in order to transition from an en-route airway, through a “Terminal Area”, until initiation of the final approach to an airfield.
STAR chart may describe several possible transitions to a single reporting point.
It is intended for IFR flights.
Two outstanding initiatives for major improvement and modernization of ATM into the 21st century are:
EGNOS in Europe and WAAS in the US.
GNSS and RNAV.
SESAR in Europe and FAA-NextGen in the US.
Inertial Navigation System position is derived from:
Initial position and integration of GPS velocity.
GPS satellite signals.
Initial position integration of air data speed and aircraft heading.
Initial position, aircraft speed derived as the integration of measured accelerations and aircraft attitude derived from the measured angular positions respect to the earth axis.
The INS integrates the acceleration into speed, then the speed into displacement and computes the current position starting from an initial aircraft position.
GPS accuracy depends of:
The time last from initial position.
The integration with the Inertial Navigation System.
Restrictions that may be imposed by the US DoD.
Availability of augmentation systems.
Air Temperature.
The number of satelites in view and their proper geometry.
What is the Satellite Based Augmentation System (SBAS)?:
Is a new generation of GPS satellite with enhanced accuracy and integrity.
Is a technique to enhance GPS accuracy implemented by a WAAS system in North America and EGNOS system in Europe.
Is a technique to enhance the GPS accuracy consisting in receiving error corrections by a ground station.
Is a technique to enhance the GPS accuracy consisting in receiving error corrections by a satellite.
The barometric altitude is derived from:
Pitot total pressure.
Air static pressure at sea level.
Pitot static port/pressure.
GPS data.
Atmospheric pressure.
Dead reckoning.
The effect of loss of attitude data in the cockpit:
Major, it is an essential data.
It may be catastrophic, but only combined with loss of communication.
Catastrophic, it is a critical data.
Hazardous, it is an important data.
Not important, a pilot can look out the window.
The air data, attitude, and heading is displayed to the flight crew in:
In the Engine Indication Display if the aircraft is equipped with electronic instruments (EFIS).
In dedicated instruments in the primary pilots field of view if the aircraft is equipped with traditional electromechanical-pneumatic instruments.
In the Primary Flight Displays (PFDs) if the aircraft is equipped with electronic flight instrument systems (EFIS).
The VOR system provides the absolute bearing to the airborne receiver based on:
The time taken by a pair of pulses to travel to the ground station and back to the receiver.
The modulation of the distance pulse train in amplitude by the 15 Hz and 135 Hz signals.
The phase difference between the 30 Hz reference signal and the 30 Hz variable phase signal.
Measuring the direction of arrival of a received signal to provide a relative bearing indication with respect to the centerline of the aircraft.
The TACAN system is a military radio navigation aid that:
Provides geographical coordinates based on the integration of measured accelerations.
Provides a bearing function based in the difference in phase of two pair of reference and variable phase signals. One of 15 Hz and another of 135 Hz.
Is able to provide absolute bearing and slant range to the ground station.
Has the advantage over other short range navigations systems (SRNS) as it can give both bearing and distance.
The GNSS Landing Systems are based on:
The GPS augmented by the use of other radio navigation systems.
The GLONASS system augmented by the satellites of the GPS.
GPS only.
Differential GPS (D-GPS).
GPS augmented by SBAS or GBAS.
Flight Management System computes vertical navigation guidance:
Using barometric altitude.
Using GPS position if available.
Using dead reckoning
Using VOR.
Using DME.
Using radio altimeter data.
Flight Management System navigation database:
Includes Standar Instrumented Departures (SID), Standard Instrument Arrivals (STAR) and approach procedures.
Includes data of the navigation aids inside the database area coverage.
Includes terrain elevation data
Shall meet TRCA DO-200A standard
Are generated by national authorities and Are compiled and verified by specialized agencies.
Stores the flight log data of the last 10 flights.
Includes airways, NavAids, waypoints and airports.
Includes departure, arrival and approach procedures inside the database coverage area.
Includes cruise altitudes
Are updated every 28 days
Flight Management System computes aircraft position based in:
Their own integrated position sensors.
The pilot manual inputs.
Available aircraft navigation sensors with priority on their accuracy.
VOR receiver cockpit incorporates the following function:
Course Deviation Indicator (CDI), which is a horizontal needle that moves laterally along a row of dots, each dot representing two degrees.
TO/FROM Indicator informs whether the aircraft bearing is “to” or “from” the VOR.
Omni Bearing Selector (OBS) which appears as a rotating latitude dial which provides for heading selection.
CDI can be centered by rotating the OBS.
Omni Bearing Selector (OBS) which appears as a rotating latitude dial which provides for bearing selection
Omni Bearing Selector (OBS) which appears as a rotating azimuth dial which provides for bearing selection
Course Deviation Indicator (CDI), which is a vertical needle that moves laterally along a row of dots, each dot representing two degrees.
The ADF system provides relative bearing to the ground station based on:
The difference in the depth of modulation of the received signal.
The time elapsed between the transmitted and received pair of pulses.
Is based on measuring the direction of arrival of a received signal to provide a relative bearing indication with respect to the center line of the aircraft.
Is based on the directivity of the receiver antenna system based on the combination of a loop and a sense antenna.
The Instrument Landing System, ILS, is the primary precision approach system used internationally, providing:
Identification by a four-letter code with an “ILS” prefix
The localizer guidance using the Course Deviation Indicator (CDI) similar to a VOR radial, but with far greater accuracy
Both horizontal and vertical guidance to a runway touchdown zone.
A final Approach Fix (FAF), which provides position confirmation.
Identification by a three-letter Morse code with an “ILS” prefix.
The Microwave landing System, MLS, provides azimuth and vertical guidance to the glide path based on:
The use of a directional pattern antenna on board the aircraft able to detect the direction of arrival of the transmitted signal.
The decoding of the 400 Hz tone transmitted by the OM beacon.
The multiplexing in time of the elevation and azimuth function that transmit fan shaped beams in the horizontal and vertical planes.
The elapsed time between the “TO” and “FRO” scan of the scanning beam in elevation and azimuth.
The elapsed time between reception of the TO and FRO scan is directly related to the elevation angle of the receiving equipment
The elapsed time between reception of the TO and FRO scan is directly related to the azimuth angle of the receiving equipment
NexGen and SESAR initiatives share the common paradigm shift:
From Procedural Based Control to Surveillance Based Control
From Trajectory Based Control to Estimated Based Control
From Procedural Based control to Performance based control
One of the keys to the NextGen and SESAR concept is the “Business/Mission Trajectory‟ principle in which:
Air Navigation Service Providers (ANSP) and airport operators define together the trajectory to be flown by the airspace users
Air Navigation Service Providers (ANSP) and the airspace users define, the optimal flight path from gate to gate and provide it to the airport operators through the SWIM (System Wide Information Management)
The goal is a trajectory-based ATM system where partners optimize business and mission trajectories through common 4D trajectory information and user defined priorities in the network.
It covers all ATM information, including aeronautical, flight, aerodrome, meteorological , air traffic flow, and surveillance.
The instrument approach chart is divided into the following sections,
Portrayal of terminal segment, identification and frequencies of navaids, selected airports and special use of airspace.
Only the vertical profile with their terms and landing minima data
Low and High RNAV routes are identified into the Aeronautical Chart by the letter:
“L” and “H” respectively
“RNAV T” and “RNAV Q” respectively
Indicate which of the following CNS/ATM systems have been completed satisfactorily:
Advanced Surface and Control System (ASCS) for flight level and information via data link.
Digital Automatic Terminal Information Service (D-ATIS) and Digital VOLMET (D-VOLMET)
2-way Pre-Departure Clearance (PDC) delivery via data-link
Aeronautical Telecommunications Network (ATN).
Air Traffic Services Inter-facility Data Communication (AIDC).
Advanced Surface Movement Guidance and Control System (A- SMGCS) for airfield surveillance.
ATS Message Handling System (AMHS) for exchange of aeronautical and meteorological information.
NDB is a radio transmitter at a known location such that the signal transmitted does not include inherent directional information. Other NDB characteristics include: (MASI11)
The signals follow the curvature of the earth, so they can be received at much greater distances at lower altitudes, a major advantage over VOR
Only works together with VOR/DME because it provides additional information
It is useful when other equipment (VOR, DME) have failed.
It is operated on a frequency between LW 190kHz and 1750kHz.
NDB signals are also affected more by atmospheric conditions, mountainous terrain, coastal refraction and electrical storms, particularly at long range.
Consider a simple ring laser gyroscope consisting of a triangular cavity that contains a mixture of helium and neon at low pressure through which a current from an excitation voltage is passed: (MASI11)
The amplitude of the phase shift will be proportional to the coil's angular velocity and the direction of the phase shift will indicate the direction of rotation
One-half is injected into a coil of optical fiber and circulates in a clockwise direction while the other half is injected at the opposite end and circulates in the opposite direction.
The supply voltage ionizes the gas and producing a glow discharge
A high reflectivity mirror is mounted at each corner of the triangle.
What is the significance of the Satellite PRN?
Identifies the GNSS service provider
This number together with the SVN (Space Vehicle Number) identifies each satellite of the GPS constellation.
The Pseudo-Random Noise.
