MIT ICATMIT ICAT Altimetry

Standard Atmosphere Referenced29.92 inches of Hg3014 mb

Pressure AltitudeAltitude of Pressure in Std AtmosphereUsed above reference Flight Level (FL180 in US)

Density AltitudeAltitude of density in Std AtmosphereUsed for performance (TO)

Barometric AltitudeEstimated altitude corrected for surface pressureMSL Altitude above Mean Sea Level (QNH)AGL Altitude above Ground Level (QFE)

Radar Altitude (Cat II and III Approaches)5 cm radar - normally only below 3000ft (Terrain Noise)

Cabin Altitude (Pressurization)

MIT ICATMIT ICAT Airspeed

Pneumatic Measurement based on Dynamic PressurePitot and Static

Indicated AirspeedIndicated on InstrumentMeasurement of pressure on Aircraft (ie Load)Used for structural operating limits

Calibrated AirspeedPitot-Static Errors Calibrated outUsed for Flight Test and Performance

GroundspeedAchieved speed over ground

Mach NumberRequires Static Air Temperature

MIT ICATMIT ICAT Air Data Sensors

Pitot TubeHeated for De-Ice

Static PortLocation SensitiveTypically 1/3 Back on Fuselage on Conventional aircraftBilateral with crosstie to avoid Side Slip ErrorsWater Drain

Alpha VaneHeated for De-Ice

TAT ProbeInertial Separator for WaterHeated for De-Ice

MIT ICATMIT ICAT Temperature

Static Air Temperature

Ram Rise

Total Air Temperature

MIT ICATMIT ICAT Integrated Air Data Systems

Air Data ComputerCompensates out Static System ErrorsCitation Example

Air Data Heading and Reference Systems (ADHARS)

MIT ICATMIT ICAT Heading

Magnetic CompassVariation (Magnetic DeviationDeviation (Magnetic materials)

DC9 ExampleCompass Card (Calibrated with Radios and Equip on)

Flux Gate CompassElectronic Magnetic Compass

Normally in Tail for deviation

Gyro CompassPrecessionSlaved Flux Gate

Turn Coordinator(Rate Gyro)

MIT ICATMIT ICAT Inertial Reference Unit

Integrate acceleration from known position and velocityVelocityPosition

Need HeadingGyros

MechanicalLaser

Can get AttitudeArtificial Horizon (PFD. HUD)

Drift ErrorsIRU unusable in vertical direction (need baro alt)Inflight Correction

DMEGPSStar Sighting for Space Vehicles

Measurement Give Attitude Also

777 Analytical Redundancy

MIT ICATMIT ICAT Communications

RequirementsCommunicate necessary information between formation elements andcommand node (LAN and Air-Ground)BandwidthLow-Observable?Synchronous vs asynchronous

ConstraintsSpectrumAntenna Location

TechnologiesRadio

UHF, VHF, MMWOptical

LaserProtocols

MIT ICATMIT ICAT COMMUNICATION

VoiceVHF (line of sight)

118.0-135.0 Mhz.025 spacing in US, 0.083 spacing in Europe)

UHF 230-400 Mhz (guess)

HF (over the horizon)Optical (secure)

DatalinkACARS (VHF) - VDL Mode 2VDL Modes 3 and 4 (split voice and data) HF Datalink (China and Selcal)

Geosynchronous (Inmarsatt)Antenna Requirements

LEO and MEO Networks

Software Radios

Antenna Requirements

MIT ICATMIT ICAT Bandwidth Growth Trend

Source: DOD UAVRoadmap, 2000

MIT ICATMIT ICAT

Navigation (relates to Surveillance)

RequirementsGeneral Navigation (medium precision)Station Keeping (high precision)IntegrityAvailability

ConstraintsExisting nav systemsLoss of signal

TechnologiesGPS/Galileo (need Differential)

Code vs Carrier Phase ApproachesIRS/GPSSensor Based Approaches for Station Keeping

Image (Visible, IR)Range Finders (Laser, Ultrasonic)

MIT ICATMIT ICAT NAVIGATION (ENROUTE)

Radionavigation beaconVHF Omnidirectional Range (VOR)Non-Directional Beacon (NDB)Distance Measuring Equipment (DME)TACAN

Area navigation systems (ground based)OmegaLORAN

Inertial navigation systems

Satellite navigation systemsGPS (CA)GNSS (Galileo?)

MIT ICATMIT ICAT GPS

From http://www.Colorado.Edu/geography/gcraft/notes/gps/gps_f.html

(Courtesy of Peter Dana. Used with permission.)

MIT ICATMIT ICAT GPS

From http://www.colorado.Edu/geography/gcraft/notes/gps/gps_f.html

Courtesy of Peter H. Dana, The Geographer's Craft Project, Department of Geography, The University of Colorado at Boulder. Used with permission.

MIT ICATMIT ICAT

GPS ISSUES

RequirementsAccuracyIntegrityAvailability

Selective Availability (SA)Degraded to 100m accuracy

Control by US DoDInternational concerns

US guarantee of service free to worldthrough 2005

Vulnerability to jamming

DGPSWAASEGNOSLAAS

MIT ICATMIT ICAT

NAVIGATION TRENDS (APPROACH)

Instrument Landing System (ILS)Cat. I (200 ft; 1/4 mile)Cat. II (50 ft; 800 RVR)Cat. III (0,0)

Microwave Landing System (MLS)

GPS (100m)Wide Areas Augmentation System (5m)

LNAV-VNAV (250, 1/4 mile)Local Area Augmentation System (0.1m)

Cat. III?

Change to Required Navigation Performance (RNP)RNP X X is 95% lateral containment on NM

MIT ICATMIT ICAT

NAVIGATION TRENDS (APPROACH)

MIT ICATMIT ICAT

NAVIGATION TRENDS (APPROACH)

MIT ICATMIT ICAT

GPS Approach Navigation

RequirementsAccuracy (RNP)AvailabilityIntegrity

Differential GPSWide Area Augmentation System (WAAS)Local Area Augmentation System (LAAS)

MIT ICATMIT ICAT

Surveillance

RequirementsObserved states of lead elements sufficient to form-up and maintain Feed forward states (intent)

ConstraintsSight AnglesInstallation (weight, cost, power, etc)Cooperative Targets

TechnologiesAutomatic Dependant Surveillance Broadcast (ADS-B)Image Based Systems (Vis, IR)Radar (X Band, MMW0Range Finders (Laser)Sensor Fusion Systems

MIT ICATMIT ICAT RADAR

Weather Radar (10 CM)

Search and TrackDoppler

Synthetic Aperture Radar

Radar Altimeter

MIT ICATMIT ICAT RADAR

Wavelength λS Band (10 cm)X Band (3 cm)Ku Band (1 (cm)Millimeter Wave (94 Ghz pass band)

Radar Range Equation

Beamwidth ΘΘ = λ/DD = Diameter of Circular AntennaPencil beam vs Fan Beam

Mechanically Steered AntennasScan and Tilt

MIT ICATMIT ICAT Imaging and Night Vision Systems

InfraredSpecial Optics (eg Gallium Arsinide)Water ContaminationSensor Cooling Requirements

Image Intensifier Systems

Pointing Systems

MIT ICATMIT ICAT Datalink Based Systems

JTIDS

Mode S TranspondersTraffic Information Service

ADS-B

MIT ICATMIT ICAT

Self Reporting Aircraft StatesADS-B

Bob HilbUPS/Cargo Airline Association

(Image removed due to copyright considerations.)

MIT ICATMIT ICAT

INTENT REPRESENTATION(consider other states)

Intent formalized in “Surveillance State Vector”

Accurately mimics intent communication & execution in ATC

⎪⎪⎪⎪

⎭

⎪⎪⎪⎪

⎬

⎫

⎪⎪⎪⎪

⎩

⎪⎪⎪⎪

⎨

⎧

D(t) states, nDestinatioT(t) states, trajectory Planned

C(t) states, target CurrentA(t) states, onAccelerati

V(t) states,Velocity P(t) states, Position

Traditional dynamicstates

Defined intentstates

Surveillance StateVector, X(t) =

FMS

Currenttarget state, C(t)

Destination, D(t)

Plannedtrajectory, T(t)

MCP

PILOT

MIT ICATMIT ICAT

ADS-B SURVEILLANCE ENVIRONMENT

Potential access to more states (e.g. dynamic and intent)

Need to assess benefits for conformance monitoring

A/CINTENT

CONTROLSYSTEM

AIRCRAFTDYNAMICS

Position, P(t)Velocity, V(t)Accel., A(t)

PILOTINTENT

Targetstates,

Guidancemode

Nav.accuracye.g. ANP

Controlsurfaceinputs

A/cproperty

e.g. weight

Trajectory,Destination

Position,Baro altitude

Heading, SpeedsRoll, ...

Targetstates

ACTUAL SYSTEM REPRESENTATION

Trajectory

ADS-B SURVEILLANCE SYSTEM

Other usefulstates???

MIT ICATMIT ICAT Engine Instrumentation

Rotation RatesN1

Exhaust Pressure Ratio

TemperaturesTurbine Inlet Temperature

Oil Pressure

Oil Temp

Vibration

MIT ICATMIT ICAT Warning Systems

Master CautionFireLow Pressure (eg oil)…

Stall WarningStick Shaker

Traffic Collision Avoidance System (TCAS)

Enhanced Ground Proximity Warning System (EGPWS)

Envelope Protection

MIT ICATMIT ICAT Envelope Protection

FlyFly--byby--wire protection wire protection -- Normal LawNormal Law

Pitchattitude

Loadfactor

High*AOA

Bankangle

Overspeed

* Angle of Attack (AOA)* Angle of Attack (AOA)

Ground mode

Flaremode

Flight mode

Flight mode

Takeoffmode

Ground mode

MIT ICATMIT ICAT

VLS

Vα Prot

Vα Max

Vα Floor

140

120

CLAirspeed scalescale

α Angle of Attack (AOA)

α Stall: Sudden loss of lift and or aircraft control

Angle of attack reached with full aft stick (max aircraft performance) Angle of attack, where TOGA thrust isautomatically applied by the A/THRAngle of attack from which stick input is converted into angle of attack demand (stick neutral α Prot)

α VLS: Angle of attack reached at approach speed (VLS)

α Max:

α Prot:

α Floor:

High Angle of Attack Protection

CL