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1、2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,1,民航導航系統原理與應用,成大民航研究所詹劭勳 老師,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,2,Course Information Books,Avionics Navigation Systems,M.Kayton,W.R.Fried,John,ISBN:0471547956 Many reference books(Keywords:GPS,INS):Global Positioning System(GPS):Signals,Measurements and Performa
2、nce,P.Misra and P.Enge,Ganga-Jamuna,2001Strapdown Inertial Navigation Systems,D.H.Titterton and J.L.WestonThe Global Positioning System and Inertial Navigation,Farrell and Barth,McGraw-Hill,1999Integrated Aircraft Navigation,J.L.Farrell,Academic Press,1976Global Positioning Systems,Inertial Navigati
3、on and Integration,Grewal,Weill and Andrews,Wiley Interscience,2001,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,3,Outline,Part 1:IntroductionPart 2:Navigation CoordinatePart 3:Radio Navigation SystemsPart 4:Global Positioning SystemPart 5:Augmentation Systems,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,4,Part 1:I
4、ntroduction An Overview of Navigation and Guidance,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,5,Navigation and Guidance,Navigation:The process of determining a vehicles/persons/objects positionGuidance:The process of directing a vehicle/person/object from one point to another along some desired path,2023/
5、6/30,(c)Shau-Shiun Jan,IAA,NCKU,6,Example,Getting from AA building to Tainan Train StationHow would you tell someone how to get there?How would you tell a robot to get there?Both problems assume there is some agreed upon coordinate system.Latitude,Longitude,Altitude(Geodetic)North,East,Down with res
6、pect to some originAd Hoc system(“starting from AA building you go 1 block”)Most of our work in this class is going to be with the Navigation problem,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,7,Applications,Air TransportationMarine,Space,and Ground VehiclesPersonal Navigation/Indoor NavigationSurveying,2
7、023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,8,A Navigation or Guidance System,Steering commands:instructions on what to do to get the vehicle going to where it should be goingTurn right/leftGo up/downSpeed up/slow down,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,9,Navigation State/State Vector,A set of parameters
8、describing the position,velocity,altitude of a vehicleNavigation state vector:Position=3 coordinates of location,a 3x1 vectorVelocity=derivative of the position vector,a 3x1 vectorAttitude=a set of parameters which describe the vehicles orientation in space,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,10,Po
9、sition and Velocity,More often than not,we are interested in position and velocity vectors expressed in separate coordinates(more on this later),2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,11,Attitude,We will deal with two ways of describing the orientation of two coordinate framesEuler angles:3 angles des
10、cribing relationship between 2-coordinate systemsTransformation matrix:maps vector in“A”coordinate frame to“B”,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,12,Attitude(continued),The first entry of the attitude“vector”,is called yaw or heading.,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,13,Navigation and Guidance
11、 Systems,In this class we will look at ways to determining some or all of the components of the navigation state vector.Some navigation systems provide all of the entries of the navigation state vector(inertial navigation systems)and some only provide a subset of the state vector.Guidance systems gi
12、ve instructions on how to achieve the desired position.,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,14,Navigation and Guidance Systems,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,15,Categories of Navigation,Dead ReckoningPositioning(position fixing)Navigation systems are either one of the two or are hybrids.,2023
13、/6/30,(c)Shau-Shiun Jan,IAA,NCKU,16,Dead Reckoning Systems,“Extrapolation”system:position is derived from a“series”of velocity,heading,acceleration or rotation measurements relative to an initial position.To determine current position you must know history of past positionHeading and speed or veloci
14、ty systemsInertial navigation systemsSystem accuracy is a function of vehicle position trajectory,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,17,Positioning/Position Fixing Systems,Determine position from a set of measurements.Knowledge of past position history is not requiredMapping system Pilotage(pp.504
15、-505)Celestial systems Star TrackersRadio systems VOR,DME,ILS,LORANSatellite systems GPS,GLONASS,GalileoSystem accuracy is independent of vehicle position trajectory,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,18,Brief History of Navigation,Land Navigation“pilotage”traveling by reference to land marks.Mari
16、ne Navigation Greeks(300350 B.C.)Record of going far north as Norway,“Periodic Scylax”(Navigation manual).Vikings(1000 A.D.)had compassFerdinand Magellan(1519)recorded use of charts(maps),devices for getting star fixes,compass,hour glass and log(for speed).The important point to note is that these e
17、arly navigators were using dead reckoning and position fixing(hybrid system),2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,19,Determine Your Latitude,Polaris,Equators,=Latitude,h,s,RE,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,20,How do you determine longitude?,Dead reckoningCompass for heading,log for speedNot ve
18、ry accurate,heading errors,speed errors position errorsErrors grow with time,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,21,The Longitude Problem,Longitude act of 171420,000 for 1/2o solution15,000 for 2/3o solution10,000 for 1o solution(about 111km resolution at equator!)Board of longitudeHalley(“Halley C
19、omet”)NewtonSolution turned out to be a stable watch/clock,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,22,20th Century and Aviation,Position fixing(guidance)systems:PilotageFires(1920)US mail routesRadio beaconsLate 1940s most of the systems we use today started entering servicesBy 1960s VOR/DME and ILS be
20、come standard in commercial aviationDead reckoningInertial navigation(1940)German v-2 RocketNuclear submarine(US NAVY)Oceanic commercial flight,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,23,20th Century and Aviation,Satellite based navigation systemsUS NAVY Transit System(1964)Global Positioning System197
21、8 first satellite launched1995 declared operationalOther satellite navigation systemsGLONASS Former Soviet UnionGalileo being developed by the EU,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,24,Performance Metrics and Trade-Off,CostAutonomyCoverageCapacityAccuracyAvailabilityContinuityIntegrityArea of activ
22、e research:5,6,7,8Accuracy:we will visit it in detail later on.,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,25,Part 2:Navigation Coordinate Frames,Transformations and Geometry of Earth.,Navigation coordinate framesGeometry of earth,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,26,Coordinate Frames,The position vect
23、or(the main output of any navigation system and our primary concern in this class)can be expressed in various coordinate frames.Notation,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,27,Why Multiple Coordinate Frames?,Depending on the application at hand some coordinates can be easier to use.In some applicat
24、ions,multiple frames are used simultaneously because different parts of the problem are easier to manage.For example,GPS:normally position and velocity in“ECEF”INS:normally position in geodetic and velocity in“NED”,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,28,Coordinate Frames,CartesianECEFECINED(locally
25、 tangent Frames)ENU(locally tangent Frames),Spherical/cylindricalGeodeticAzimuth-Elevation-Range Bearing-Range-Attitude,Except for ECI,all are non-inertial frames,an inertial frames is a non-accelerating(translation and rotation)coordinate frames.,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,29,ECEF and ECI
26、,Earth Centered and Earth Fixed(ECEF)Cartesian Frame with origin at the center of earth.Fixed to and rotates with earth.A non-inertial frame.Earth Centered Inertial(ECI)Cartesian frame with origin at earths center.Z axis along earths rotation vector.X-y plane in equatorial plane.,2023/6/30,(c)Shau-S
27、hiun Jan,IAA,NCKU,30,Geodetic,Geodetic(Latitude,Longitude,Altitude)SphericalLatitude()=north south of equator,range 90oLongitude()=east west of prime meridian,range 180oAltitude(h)=height above reference datum“+”north latitude,east longitude,down(below)datum altitude,2023/6/30,(c)Shau-Shiun Jan,IAA,
28、NCKU,31,NED and ENU,North-East-Down(NED)CartesianNo fixed location for the originLocally tangent to earth at originEast-North-Up(ENU)CartesianSimilar to NED except for the direction of 1-2-3 axes.,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,32,Azimuth-Elevation-Range,Azimuth-Elevation-RangeSphericalNo fixe
29、d originAzimuth is angle between a line connecting the origin and the point of interest(in the tangent plane)and a line from origin to north poleElevation is the angle between the local tangent plane and a line connecting the origin to a point of interestRange is the slant or line-of-sight distance,
30、2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,33,Azimuth-Elevation-Range,Two types of azimuth or heading anglesTrue:measured with respect to the geographic(true)north pole(T)Magnetic:measured with respect to the magnetic north pole(M),2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,34,Earth Magnetic Field,1st order app
31、roximation is that of a simple dipolePoles move with time.In 1996 magnetic north pole was located at(79oN,105oW)In 2003 it is located at(82oN,112oW)Also,can“wander”by as much as 80km per day,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,35,Earth Magnetic Field,Magnetic poles are used in navigation because M
32、is easier to measure than T Bx and By are measured by devices called magnetometers(Ch.9)Anomalies such as local iron deposits lead to erroneous M readingIron range deposits of N.E.Minnesota can lead to errors as large as 50o,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,36,Shape/Geometry of Earth,Topographic
33、al/physical surfaceGeoidReference ellipsoid,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,37,Shape/Geometry of Earth(continued),Topographical surface shape assumed by earths crust.Complicated and difficult to model mathematically.Geoid an equipotential surface of earths gravity field which best fits(least sq
34、uares sense)global mean sea level(MSL)Reference ellipsoid mathematical fit to the geoid that is an ellipsoid of revolution and minimizes the mean-square deviation of local gravity(i.e.,local norm to geoid)and ellipsoid norm,WGS-84,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,38,Latitude,2023/6/30,(c)Shau-Sh
35、iun Jan,IAA,NCKU,39,WGS84,Four defining parametersOther parameters are derived from the fourEquatorial radius=6378.137kmFlattening=1/298.257223563Rotation rate of earth in inertial space=15.041067 degree/hourEarths gravitational constant(GM)=3.986004x108m3/s2,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,40,
36、Part3:Radio Navigation Systems I:Fundamentals,I:FundamentalsII:Survey of Current Systems,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,41,Radio Navigation Systems,These are systems that use Radio Frequency(RF)signals to generate information required for navigation.C=speed of electromagnetic waves in free spa
37、ce(“speed of light”)“Radio waves”correspond to electromagnetic waves with frequency between 10 KHz and 300 GHz,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,42,Frequency,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,43,Frequency,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,44,Radio Signal Propagation(1/3),Ground WavesWaves b
38、elow the HF range(i.e.,3 MHz)Unpredictable path characteristicsRequired large antennaAtmospheric noise,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,45,Radio Signal Propagation(2/3),Line of Sight Waves:Signals 30 MHz100 MHz 3 GHz predictableAbove 3 GHz absorptionAbove 10 GHz discrete absorption,2023/6/30,(c)
39、Shau-Shiun Jan,IAA,NCKU,46,Radio Signal Propagation(3/3),Sky WavesHF and below(i.e.,30 MHz)MultipathFadingSkip distance:depends of frequency and ionosphere conditions,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,47,Modulation Techniques,Modulation how you place information of the RF signalAmplitude modulati
40、on(AM)change the amplitude of sinusoid to relay information Frequency modulation(FM)change in frequency of transmitted signal to relay informationPhase modulation(PM)change phase of transmitted signal to relay informationThe signal can be transmitted as a pulse or a continuous wave.Either one can be
41、 modulated by the above methods.,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,48,How do you distinguish one beacon from another?,Frequency division multiple access(FDMA)each transmitter/beacon uses a different frequency Time division multiple access(TDMA)each transmitter/beacon transmits at a specified time
42、Code division multiple access(CDMA)each transmitter/beacon uses an identifier code to distinguish itself from the other transmitters or beacons,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,49,Important Conclusions,Low frequency systems ground wave transmission long range systems,Loran.High frequency systems
43、 line of sight systems,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,50,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,51,Phases of Flight,Takeoff,Departure(Climb),En Route,Approach(Descent),Landing,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,52,Phases of Flight,Takeoff Starts at takeoff roll and ends when climb is establish
44、ed.Departure Ends when the aircraft has left the so called terminal area.En Route Majority of a flight is spent in this phase.Ends when the approach phase begins.Navigation error during this phase must be less than 2.8 N.M(2-)over land and 12 N.M over oceans.,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,53,
45、En Route,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,54,Phases of Flight,Approach Ends when the runway is in sight.The minimum descent altitude or decision height is reached.(MDA or DH)Landing Begins at the MDA or DH and ends when the aircraft leaves the runway.,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,55,Accu
46、racy Requirement,Accuracy required during the approach and landing phases of flight depend on the type of operation being conducted.,*Used by the ground based controllers to give the user“steering“directions and to ensure traffic separation between aircraft.,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,56,V
47、OR,VOR(VHF Omni-Directional Range)Provides bearing informationUses VHF radio signalsFDMA with frequencies between 112 and 117.95 MHZBearing accuracy 1o to 3oWorks by comparing the phase of 2 sinusoids.One has bearing dependent phase the other doesnt.,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,57,DME,DME(D
48、istance Measuring Equipment):Measures slant range Operates between 962 1213 MHzAccuracy 0.1 to 0.17 n.m.(nominal)(185 315 m)Principle of operationAirborne unit sends a pair of pulsesGround based beacon(transponder)picks up the signalAfter a 50sec delay,transponder repliesAirborne unit receives pulse
49、 pair and computes range by:,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,58,DME,How does a particular user distinguish their pulse from that of other users?Normally,VOR and DME are collocated,in the U.S.there are 1000 VOR/DME beacons.,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,59,ILS,ILS(Instrument Landing Syste
50、m):System provides angular information Used exclusively for approach and landing,2023/6/30,(c)Shau-Shiun Jan,IAA,NCKU,60,ILS,It provides information about deviation from the center line()and guide slope()Includes marker beacons that are installed at discrete distances from the runway.Outer Marker(OM
