MIT ICAT Altimetry y Standard Atmosphere Referenced ? 29.92 inches of Hg ? 3014 mb y Pressure Altitude ? Altitude of Pressure in Std Atmosphere ? Used above reference Flight Level (FL180 in US) y Density Altitude ? Altitude of density in Std Atmosphere ? Used for performance (TO) y Barometric Altitude ? Estimated altitude corrected for surface pressure ? MSL Altitude above Mean Sea Level (QNH) ? AGL Altitude above Ground Level (QFE) y Radar Altitude (Cat II and III Approaches) ? 5 cm radar - normally only below 3000ft (Terrain Noise) y Cabin Altitude (Pressurization) MIT ICAT Airspeed y Pneumatic Measurement based on Dynamic Pressure ? Pitot and Static y Indicated Airspeed ? Indicated on Instrument ? Measurement of pressure on Aircraft (ie Load) ? Used for structural operating limits y Calibrated Airspeed ? Pitot-Static Errors Calibrated out ? Used for Flight Test and Performance y Groundspeed ? Achieved speed over ground y Mach Number ? Requires Static Air Temperature MIT ICAT Air Data Sensors y Pitot Tube ? Heated for De-Ice y Static Port ? Location Sensitive ? Typically 1/3 Back on Fuselage on Conventional aircraft ? Bilateral with crosstie to avoid Side Slip Errors ? Water Drain y Alpha Vane ? Heated for De-Ice y TAT Probe ? Inertial Separator for Water ? Heated for De-Ice MIT ICAT Temperature y Static Air Temperature y Ram Rise y Total Air Temperature MIT ICAT Integrated Air Data Systems y Air Data Computer ? Compensates out Static System Errors ? Citation Example y Air Data Heading and Reference Systems (ADHARS) MIT ICAT Heading y Magnetic Compass ? Variation (Magnetic Deviation ? Deviation (Magnetic materials) ? DC9 Example ? Compass Card (Calibrated with Radios and Equip on) y Flux Gate Compass ? Electronic Magnetic Compass ? Normally in Tail for deviation y Gyro Compass ? Precession ? Slaved Flux Gate y Turn Coordinator ? (Rate Gyro) MIT ICAT Inertial Reference Unit y Integrate acceleration from known position and velocity ? Velocity ? Position y Need Heading ? Gyros ? Mechanical ? Laser y Can get Attitude ? Artificial Horizon (PFD. HUD) y Drift Errors ? IRU unusable in vertical direction (need baro alt) ? Inflight Correction ? DME ? GPS ? Star Sighting for Space Vehicles y Measurement Give Attitude Also y 777 Analytical Redundancy MIT ICAT Communications y Requirements ? Communicate necessary information between formation elements and command node (LAN and Air-Ground) ? Bandwidth ? Low-Observable? ? Synchronous vs asynchronous y Constraints ? Spectrum ? Antenna Location y Technologies ? Radio ? UHF, VHF, MMW ? Optical ? Laser ? Protocols MIT ICAT COMMUNICATION y Voice ? VHF (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) y Datalink ? ACARS (VHF) - VDL Mode 2 ? VDL Modes 3 and 4 (split voice and data) ? HF Datalink (China and Selcal) y Geosynchronous (Inmarsatt) ? Antenna Requirements y LEO and MEO Networks y Software Radios y Antenna Requirements MIT ICAT Bandwidth Growth Trend Source: DOD UAV Roadmap, 2000 MIT ICAT Navigation (relates to Surveillance) y Requirements ? General Navigation (medium precision) ? Station Keeping (high precision) ? Integrity ? Availability y Constraints ? Existing nav systems ? Loss of signal y Technologies ? GPS/Galileo (need Differential) ? Code vs Carrier Phase Approaches ? IRS/GPS ? Sensor Based Approaches for Station Keeping ? Image (Visible, IR) ? Range Finders (Laser, Ultrasonic) MIT ICAT NAVIGATION (ENROUTE) y Radionavigation beacon ? VHF Omnidirectional Range (VOR) ? Non-Directional Beacon (NDB) ? Distance Measuring Equipment (DME) ? TACAN y Area navigation systems (ground based) ? Omega ? LORAN y Inertial navigation systems y Satellite navigation systems ? GPS (CA) ? GNSS (Galileo?) MIT ICAT GPS From http://www.Colorado.Edu/geography/gcraft/notes/gps/gps_f.html (Courtesy of Peter Dana. Used with permission.) MIT 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 ICAT GPS ISSUES y Requirements ? Accuracy ? Integrity ? Availability y Selective Availability (SA) ? Degraded to 100m accuracy y Control by US DoD ? International concerns y US guarantee of service free to world through 2005 y Vulnerability to jamming y DGPS ? WAAS ? EGNOS ? LAAS MIT ICAT NAVIGATION TRENDS (APPROACH) y Instrument Landing System (ILS) ? Cat. I (200 ft; 1/4 mile) ? Cat. II (50 ft; 800 RVR) ? Cat. III (0,0) y Microwave Landing System (MLS) y GPS (100m) ? Wide Areas Augmentation System (5m) ? LNAV-VNAV (250, 1/4 mile) ? Local Area Augmentation System (0.1m) ? Cat. III? y Change to Required Navigation Performance (RNP) ? RNP X ? X is 95% lateral containment on NM MIT ICAT NAVIGATION TRENDS (APPROACH) MIT ICAT NAVIGATION TRENDS (APPROACH) MIT ICAT GPS Approach Navigation y Requirements ? Accuracy (RNP) ? Availability ? Integrity y Differential GPS ? Wide Area Augmentation System (WAAS) ? Local Area Augmentation System (LAAS) MIT ICAT Surveillance y Requirements ? Observed states of lead elements sufficient to form-up and maintain ? Feed forward states (intent) y Constraints ? Sight Angles ? Installation (weight, cost, power, etc) ? Cooperative Targets y Technologies ? Automatic Dependant Surveillance Broadcast (ADS-B) ? Image Based Systems (Vis, IR) ? Radar (X Band, MMW0 ? Range Finders (Laser) ? Sensor Fusion Systems MIT ICAT RADAR y Weather Radar (10 CM) y Search and Track ? Doppler y Synthetic Aperture Radar y Radar Altimeter MIT ICAT RADAR y Wavelength λ ? S Band (10 cm) ? X Band (3 cm) ? Ku Band (1 (cm) ? Millimeter Wave (94 Ghz pass band) y Radar Range Equation y Beamwidth Θ ? Θ = λ/D ? D = Diameter of Circular Antenna ? Pencil beam vs Fan Beam y Mechanically Steered Antennas ? Scan and Tilt MIT ICAT Imaging and Night Vision Systems y Infrared ? Special Optics (eg Gallium Arsinide) ? Water Contamination ? Sensor Cooling Requirements y Image Intensifier Systems y Pointing Systems MIT ICAT Datalink Based Systems y JTIDS y Mode S Transponders ? Traffic Information Service y ADS-B MIT ICAT Self Reporting Aircraft States ADS-B Bob Hilb UPS/Cargo Airline Association (Image removed due to copyright considerations.) MIT ICAT INTENT REPRESENTATION (consider other states) y Intent formalized in “Surveillance State Vector” y Accurately mimics intent communication & execution in ATC ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? D(t) states, nDestinatio T(t) states, trajectory Planned C(t) states, target Current A(t) states, onAccelerati V(t) states,Velocity P(t) states, Position Traditional dynamic states Defined intent states Surveillance State Vector, X(t) = FMS Current target state, C(t) Destination, D(t) Planned trajectory, T(t) MCP PILOT MIT ICAT ADS-B SURVEILLANCE ENVIRONMENT y Potential access to more states (e.g. dynamic and intent) y Need to assess benefits for conformance monitoring A/C INTENT CONTROL SYSTEM AIRCRAFT DYNAMICS Position, P(t) Velocity, V(t) Accel., A(t) PILOT INTENT Target states, Guidance mode Nav. accuracy e.g. ANP Control surface inputs A/c property e.g. weight Trajectory, Destination Position, Baro altitude Heading, Speeds Roll, ... Target states ACTUAL SYSTEM REPRESENTATION Trajectory ADS-B SURVEILLANCE SYSTEM Other useful states??? MIT ICAT Engine Instrumentation y Rotation Rates ? N1 y Exhaust Pressure Ratio y Temperatures ? Turbine Inlet Temperature y Oil Pressure y Oil Temp y Vibration MIT ICAT Warning Systems y Master Caution ? Fire ? Low Pressure (eg oil) ? … y Stall Warning ? Stick Shaker y Traffic Collision Avoidance System (TCAS) y Enhanced Ground Proximity Warning System (EGPWS) y Envelope Protection MIT ICAT Envelope Protection Fly-by-wire protection - Normal Law Pitch attitude Load factor High *AOA Bank angle Overspeed * Angle of Attack (AOA) Ground mode Flare mode Flight mode Flight mode Takeoff mode Ground mode MIT ICAT VLS Vα Prot Vα Max Vα Floor 140 120 CL Airspeed scale 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 is automatically applied by the A/THR Angle 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