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Scenario Generation

Scenario Generation. Agenda. Controlling the desired satellite constellation Defining vehicle types and motion Using antenna patterns Multiple vehicles and antennas. Creating a Scenario.

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Scenario Generation

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  1. Scenario Generation Proprietary & Confidential—Page 1

  2. Agenda • Controlling the desired satellite constellation • Defining vehicle types and motion • Using antenna patterns • Multiple vehicles and antennas

  3. Creating a Scenario • Depending upon the test purpose, several considerations impact the scenario definition for testing a receiver • These considerations include: • The vehicle motion – Static or Dynamic dynamics, the performance envelope for vehicle linear and angular dynamics • The satellite behavior – The transmitted codes and frequencies, power levels, satellite ephemeris definitions and transmitted navigation data • The representative environmental conditions – Atmosphere, terrain or vehicle obscuration, multipath, or interference • The vehicle antenna characteristics – The antenna gain and phase patterns, lever arms, boresight or antenna switching • The desired start date and time – Present day for what is in the sky now, History for forensics or in the Future for upcoming Launches or impacts of new constellations • Maybe augmentation systems are necessary - WAAS, LAAS, etc. Proprietary & Confidential—Page 3

  4. Agenda • Controlling the desired satellite constellation • Defining vehicle types and motion • Using antenna patterns • Multiple vehicles and antennas

  5. Controlling the Desired Satellite Constellation • How should the satellite constellation be simulated? Current almanac? Modified almanac? Errors? • Several attributes impact the simulated satellite constellation • The almanac defined in the scenario is used by SimGEN for simulating the satellite orbits and navigation data used by the receiver for navigation • Other constellation considerations include: • Defining the number of satellites to simulate in the scenario with typically 30-32 satellites available today • Specifying the desired frequencies and codes transmitted from each satellite since there are some “modernized” Block-IIR-M satellites in the sky transmitting L2C and M-code with Block-IIF satellites on the way that will transmit L5 • Errors in the orbital positions or satellite clocks Proprietary & Confidential—Page 5

  6. GPS Navigation Data Overview • The orbital parameters are included in the navigation data for use by the receiver to calculate the range to each satellite for positioning • These orbital parameters are transmitted to the Users in two forms: • Almanac – Basic Orbital Information • The almanac provides basic (coarse) information about all space vehicle (SV) orbital position’s in the constellation • It is transmitted by all SVs in Subframes 4 and 5 of the navigation data • Ephemeris – Enhanced Detailed Information • The ephemeris provides detailed information about the SV orbital position using more accurate orbital parameters • Each SV transmits the ephemeris parameters only for itself in Subframes 2 and 3 Proprietary & Confidential—Page 6

  7. GPS Navigation Data Overview (cont.) • In addition to the orbital parameters, the navigation data also includes: • Satellite clock corrections, health indicators, age of data • Ionosphere model parameters, UTC data, SVID (space vehicle identification) • The navigation data is broadcast to the User Segment at 50 bits/s, thus it takes time to download by the receiver after tracking each satellite • It takes 12.5 minutes for a complete almanac to be transmitted • Ephemeris data is broadcast by each SV every 30 seconds • In practice, new ephemeris is uploaded to each SV roughly every 2 hours • This is also why receivers may track a satellite for 30 seconds before using it in its navigation solution Proprietary & Confidential—Page 7

  8. Signal Sources File • Allows definition of all the satellite constellation parameters • Orbits for each satellite • Satellite ephemeris and navigation data errors • Satellite clock errors • Satellite transmitted signal definition (C/A,P,nav data, L1,L2, etc.) • Transmitted signal powers • Navigation data definition, modification, and uploads Proprietary & Confidential—Page 8

  9. Signal Sources File – General Page • The General Page allows the user to specify general satellite parameters as described below: • Shown are the default settings • Signal Strength setting • Modelled = Strength depends on parameters like SV distance etc • Fixed = Signal set fixed at set level • Diverge Ephemeris • Disabled (Default) or Enabled • Enabling it affects the Ephemeris data transmitted in the nav data only and not the actual RF signal • Error simulates degradation from late uploads, such as an inoperable Control Segment • The ephemeris degradation profile typically follows the 95% UERE graph in the STANAG 4294 which equates to an ephemeris error of roughly 400m after 14 days • The user can perform uploads to reduce errors during the scenario Nav data parameter – Issue of Data Clock NMCT/WAGE – Additional navigation data, turn on/off (Clock terms, and Track errors) Set the UTC leap seconds value This sets the fractional portion of the GPS to UTC difference + a rate difference during run Proprietary & Confidential—Page 9

  10. Specify for each satellite • Supports up to 32 satellites • Define the orbit for each satellite • Also used for defining the almanac and ephemeris data in the navigation message Signal Sources File - Orbits • The Orbits menu allows the user to easily specify and update the orbital parameters and reference times for each satellite in the constellation, in addition to selecting which satellites to be present in the constellation for a reduced constellation Proprietary & Confidential—Page 10

  11. Signal Sources File – Orbits (cont.) • The Orbits menu also allows the user to specify one of the GPS satellites to be geostationary, which is useful for various test requirements where the satellite needs to be a fixed location or when it is not desired to have satellite Doppler • Make current Satellite Geostationary • Creates a constant pseudorange signal for specific GPS receiver tests • Automatically defines the Eccentricity and Latitude as zero • Display the ground track window • Views the orbital motion and position of the satellites specified by the Ephemeris and Almanac data for ±1 hour of start time Proprietary & Confidential—Page 11

  12. More like Reality Signal Sources File - Perturbations • In reality GPS satellite orbits are more like the orbit below because of gravitational and Newtonian effects • To model this, SimGEN allows the user to specify perturbations for each satellite separately in the argument of latitude, angle of inclination and orbital radius • They also get modeled in the navigation data for correcting the perturbations by the receiver • The perturbations used are described to the right • Cuc, Cus - Amplitude of the cosine and sine harmonic correction terms to the argument of latitude • Cic, Cis - Amplitude of the cosine and sine harmonic correction terms to the angle of inclination • Crc, Crs - Amplitude of the cosine and sine harmonic correction terms to the orbital radius Proprietary & Confidential—Page 12

  13. Signal Sources File - Track Errors • Because there are errors in the satellite positions, users can input track errors to model this contributing error source for each satellite • Track errors are applied to the simulated position on the RF signal only, thus they are not corrected for in the Nav Data • Scaling ± 100m Proprietary & Confidential—Page 13

  14. Signal Sources File - Message Sequencing • The legacy Nav Data for C/A and P(Y) are automatically sequenced per ICD-GPS-200C • L2C and L5 CNav Data are structured differently and can be broadcast in any message order • The default sequencing may be sufficient, but the user can modify the sequence of CNav messages as necessary Message Types to assign to the sequence CNav message sequence Proprietary & Confidential—Page 14

  15. Specify a PRN number from 1 to 37 for the selected satellite Check ‘All’ for selected value or options to be used for All satellites • M-Modulation axis determination (In-phase or Quadrature axis) • Only applicable to GSS7700/8000 Simulators Set satellite type for setting the navigation data flag to identify broadcasting the satellite type • This allows high flexibility in what is broadcast from each satellite. The user can select: • If L1, L2 or L5 will be transmitted • Which PRN code will be simulated • Which (if any) Navigation Data sets will be used Signal Sources File - Signal Control • Using the Signal Control menu, the user can control each satellite’s PRN number and transmitted navigation data and signal characteristics • This can be used for customizing each satellite, uniquely defining the different Block SVs or modeling satellites with no navigation data for example Proprietary & Confidential—Page 15

  16. Signal Sources File - Signal Power • The Signal Power menu allows the user to define power offsets for each signal, code and satellite • The user can specify a global offset of power for each satellite • Used as the reference power level in “Signal strength Modelled” or absolute in “Signal strength fixed” from General menu • Useful for modifying the signal power for all satellites to obtain the desired C/No at the receiver • The user can also apply specific power offsets to each frequency and code Proprietary & Confidential—Page 16

  17. Viewing the Satellites in the Sky • The Ground Track display in the SimGEN Main Window shows the current vehicle’s position, as well as the satellite positions • It also shows which satellites are visible and being simulated • Green – Satellites are visible and are simulated • Aqua – Satellites are not visible and are not simulated • Red – Satellites are visible and are not simulated (occurs if not enough channels or banned from the constellation) Proprietary & Confidential—Page 17

  18. Viewing the Satellites in the Sky (cont.) • The Sky Plot on the SimGEN Main Window is useful for viewing the relative satellite azimuth and elevation positions in the sky • The view in the Sky Plot is from a point in space down at the vehicle as described below Elevation Increases from 0° on the outer circle to 90° at the center Proprietary & Confidential—Page 18

  19. Signals Received • The Signals Received display shows the signals, including multipath, currently being simulated that could be received by the receiver • This is a useful display for quickly viewing various signal and satellite parameters, such as PRNs, atmospheric delays, exact power levels, pseudoranges and pseudorange rates • This can be accessed by double-clicking the Sky Plot display on the Main Window or by using the shortcut in the Tool Bar as shown below Proprietary & Confidential—Page 19

  20. Agenda • Controlling the desired satellite constellation • Defining vehicle types and motion • Using antenna patterns • Multiple vehicles and antennas

  21. Vehicles and Motion • GPS receivers are used in applications ranging from spacecraft to personal navigation devices (PNDs) • Each of these ‘vehicles’ are unique with different vehicle ‘personalities’ and motion • For example a launch vehicle ‘personality’ that can accelerate up to 8 G’s isn’t realistic for testing an automobile receiver • Thus, it is important to use a representative vehicle personality and motion for the intended vehicle Proprietary & Confidential—Page 21

  22. SimGENs Vehicle Types and Motion • SimGEN supports various vehicle types for modeling in the scenario • These are the following (6) vehicle models: • Static • Simple Motion • Aircraft • Depending upon the vehicle, SimGEN uses built-in models for allowing the user to easily define the vehicles ‘personality’ to specify the intended vehicle dynamic limitations • Using these ‘personality’ files, the user can script the intended vehicle motion using time sequenced commands such as ‘accelerate’, ‘turn’, ‘climb’, ‘roll’, etc. • SimGEN also supports user generated motion for the defined vehicles • Permits logged ‘real’ data to be used or mission specific trajectories for example • Land Vehicle • Ship • Spacecraft Proprietary & Confidential—Page 22

  23. Accessing Vehicles Models in SimGEN • Available in the Scenario Contents Window, the user can add/edit/delete vehicles used in the scenario • The user can add or replace any of the 6 vehicles by right-clicking • or using the shortcuts at the bottom • The vehicle files are similar to the other scenario Source Files which are also editable in a text editor Proprietary & Confidential—Page 23

  24. Vehicle Model Source Files • The different vehicle models use unique source files for defining the: • Vehicle personality (e.g. dynamic limitations) • Vehicle commands (e.g. vehicle motion) • Other vehicle unique files (e.g. sea states) • The Aircraft and Land Vehicle models use a command and personality file only • Spacecraft has an additional reference file for defining the initial attitude, position and the gravity model definition • Ship has an additional sea states model for representing various sea conditions • Simple motion just uses a basic built-in menu for specifying the simple motion • Static just uses an initial positional reference Proprietary & Confidential—Page 24

  25. Vehicle Personality File • This file specifies the intended vehicle characteristics, for instance to model a person walking or a car, an airliner or a jet, a cruise ship or a cigarette boat • The vehicle characteristics are defined by the vehicle limitations in linear and lateral velocity, acceleration, jerk and angular roll, pitch, yaw dynamics as shown below for the Aircraft personality file for example • Each vehicle model uses different default values to represent each model type, but the user can easily modify them as necessary to represent other vehicles • Note: This file has no impact if using user generated motion data Linear Limits Roll, Pitch and Yaw Limits Proprietary & Confidential—Page 25

  26. Linear and Lateral Limits Overview • The linear and lateral limitations have an important impact on the vehicle dynamics • Below is an overview of the linear and lateral limitations specified in the personality file Linear Dynamic limits i.e. forward motion through the vehicle nose as shown to the right Forward Motion Sideways force • This is actually Max Stress acceleration and jerk • i.e. – All stresses applied to vehicle • Includes gravitational pull, forward motion, and sideways force Vehicle Proprietary & Confidential—Page 26

  27. Vehicle Personality File • The motion specified will be limited/constrained by the personality file which is necessary to model the desired vehicle • For example, specifying low lateral and linear maximum accelerations and low max speed in the aircraft personality file the user can model different vehicles • Thus if compared to a jet fighter personality, the Cessna will take longer to accelerate, fly slower and maybe turn over a larger radius as described below Small lateral acceleration for a smaller turn radius High lateral acceleration for a smaller turn radius High linear speed and acceleration Slow linear speed and acceleration Proprietary & Confidential—Page 27

  28. Static Vehicle Reference File • Static Vehicle Model – Permits the user to specify any static position which is extremely useful for various test cases, such as checking antenna patterns or test requirements that do not require dynamic conditions Question Why is there a Heading option for a static vehicle ? Answer: Because the antenna pattern is relative to the vehicle body axis Specify Lat/Long/Height of Position Proprietary & Confidential—Page 28

  29. Simple Motion (Circular) • Circular Motion is a simple motion model useful for basic motion testing where constant velocity or lateral acceleration may be desired Specify Circle Center Position Specify Radius of Circle (r) Specify Initial Bearing Radius (r) Circle Center Specify Vehicle speed (specifies direction of travel) Initial Bearing specifies where you start on the Circle Specify a static period and speed change duration to reach Speed specified! Proprietary & Confidential—Page 29

  30. Simple Motion (Rectangular Racetrack) • Rectangular racetrack is another useful basic motion model Specify Racetrack Dimensions Specify Vehicle Start condition Specify Vehicle Dynamics Set Reference Position of Racetrack Rotate Racetrack (around reference position bottom left corner) Proprietary & Confidential—Page 30

  31. Vehicle Command Files • As mentioned previously, the vehicle command file is used to script a vehicle motion command sequence • The command file editor provides a simple, common interface (same for Land Vehicle, Ship, Aircraft, Spacecraft) • Each vehicle may have unique motion commands specific to the vehicle type, such as ‘climb’ (Aircraft) or ‘orientation’ (Spacecraft) • The editor also provides a pre-check tool to verify the sequenced motion commands with the corresponding personality to verify compatibility and report any instances where the dynamics exceed the corresponding personality file • Note: The command files are not used if using User generated motion data Proprietary & Confidential—Page 31

  32. Vehicle Command Files (cont.) • Land vehicle example of using the command file editor is shown below for selecting and inserting motion commands Note: reference command always at start, specifies start position. List of motion commands, Note: executed in order! Note: changing command type will offer command specific details Use to insert commands Command specification (details) Proprietary & Confidential—Page 32

  33. Pre-check of Vehicle Command File Speed of run • After creating the sequenced motion commands, the trajectory can be cross-checked against the maximum limits held in the Personality file • Useful for checking the integrity of the specified motion Vehicle position information Vehicle Motion display (displayed at 1Hz) Command Run list showing the sequenced motion commands and any modifications because of the personality file Proprietary & Confidential—Page 33

  34. Land Vehicle Command File • Using the Vehicle Command editor described previously, several motion commands are available for easily scripting a land vehicle trajectory which are described below • Reference – Start position & Speed • Accelerate – Change vehicle speed (+ & -) • Climb command – Change height • Halt command – Bring vehicle to a stop, and then halt for specified time • Straight command – Travel in straight line • Turn Command – Change Heading • Waypoint Command – Travel to specified point Proprietary & Confidential—Page 34

  35. Ship Command File • The Vehicle Command editor also provides several motion commands for easily scripting a ship trajectory which are described below • Reference – Start position & Speed • Accelerate – Change vehicle speed (+ & -) • Halt command – Bring vehicle to a stop, and then halt for specified time • Straight command – Travel in straight line • Turn Command – Change Heading • Waypoint Command – Travel to specified point • Note: All commands allow you to select the sea state! Proprietary & Confidential—Page 35

  36. Ship Sea State File • The Sea State file provides (10) sea state models for modeling the conditions of the sea from ‘Glossy’ to ‘Phenomenal’ which are described below • All states can be modified for user preference as well • Specify for each state the Amplitude, Frequency and Phase for: • Roll • Pitch • Heave Proprietary & Confidential—Page 36

  37. Orbit Command – Special case of combined command, vehicle performs optimal accelerating climb to the required altitude and velocity Straight command – Travel in straight line. – 2 Options: Constant Heading – This keeps vehicle heading constant but does not work at the poles Great circle – Allows constant heading at pole/high latitude Turn Command - Change Heading Waypoint Command – Travel to specified point Auxiliary commands – Aircraft has some additional auxiliary commands: Axial Roll – Perform a rotation about the body X axis Axial Yaw – Perform a rotation about the body Z axis Axial Pitch – Perform a rotation about the body Y axis Also using the Vehicle Command editor described previously, several motion commands are available for easily scripting an aircraft trajectory as described below and to the right Reference – Start position & Speed Accelerate – Change vehicle speed (+ & -) Accelerating Turn command – Change Speed and Heading of vehicle Climb command – Change height Combined Command – Change vehicle Speed, Heading, and Height in one command. Done in phases: Constant Speed Turn and Climb Then once complete does the required acceleration changes Halt command – Bring vehicle to a stop, and then halt for specified time Aircraft Command File Proprietary & Confidential—Page 37

  38. Spacecraft Command File • If using the Spacecraft model, the Vehicle Command editor provides several motion commands for easily scripting a spacecraft trajectory which are described below • Acceleration – Change of thrust which will allow a modification to the orbit • Note: This is still constrained by realistic modeling of a body in orbit. • Orientation – Change Spacecraft orientation from: • Inertial – Maintain attitude w.r.t inertial reference frame. • Earth pointing – Maintain attitude w.r.t center of earth • Sun Pointing – Maintain attitude w.r.t. the sun • Rotation – Rotate spacecraft • This model takes into account: • The Earth and moon gravitational effects • The effect of Solar Radiation Proprietary & Confidential—Page 38

  39. Spacecraft Reference File • For the spacecraft model, the Vehicle Reference is no longer contained in the Command file, but is defined in a separate Reference file shown below • The spacecraft Reference file specifies the initial position and orbit • Specify initial position in either: • Orbital (i.e. orbital parameters) • Vector (i.e. ECEF) • Terrestrial (i.e. Geodetic) Initial Attitude (Sun Pointing, Inertial, or Earth Pointing). Specify Inertial co-ordinate system. Specify number of terms used in gravity model (more=More precise model, but more computational time). Specify Gravity model (earth gravitational effect on spacecraft) Proprietary & Confidential—Page 39

  40. Space Personality File • Different from the other personality files, the spacecraft personality file permits the user to also specify the vehicle aerodynamic drag and max/min altitudes for affecting the dynamics on orbit Cross sectional area of the Spacecraft (for drag calculation) How aerodynamic is the spacecraft (drag factor). Vehicle mass for gravity effects Max / Min altitude Model is valid from 80km to 450,000 km Proprietary & Confidential—Page 40

  41. Vehicle Labels The vehicles defined in the scenario can also be given a label as shown below This is particularly important for multi vehicle applications to differentiate the outputs G-Sensitivity Receiver crystal oscillators exhibit a change in output frequency when subjected to acceleration, which is known as g-sensitivity While the GPS simulator does not model the "user clock", it can impart the same frequency shift to each GPS satellite signal during vehicle acceleration to model this This is particularly useful for high dynamic testing like launch vehicles and missiles Additional SimGEN Vehicle Topics Proprietary & Confidential—Page 41

  42. User Generated Motion • Sometimes users want to use their own models or trajectories for increased flexibility or fidelity in the simulation of their vehicular dynamics • For instance to model a multi-stage launch vehicle, rocket, or other vehicles with unique mission dynamic requirements • Typically these are generated from • Internal Proprietary tools developed and used by the end user • Commercial Off the Shelf (COTS) tools • Logged “real” vehicle or flight data • This data is typically provided in different formats and reference frames • When used in SimGEN, the data must be compliant with SimGEN’s User Motion or Remote Motion data formats • SimGEN accepts 6-DOF motion data in either ECEF or Lat, Long, Height (wrt WGS84) and NED reference frames Proprietary & Confidential—Page 42

  43. User Motion Data • SimGEN’s User Motion data, specified as a *.umt file, is an ASCII text file containing 6-DOF motion data • The UMT message format is: Pos, Vel, Accel, Jerk, Attitude (Head,Elev,Bank), Body Angular Vel (x,y,z), Body Angular Accel (x,y,z) and Body Angular Jerk (x,y,z) • Two reference frame formats are supported • UMT User Motion – ECEF (default) • 0 00:00:01,6380140.13,0,71.918,4.471,0,79.875,-0.001,0,0,-4.20e-06,0,-1.27e-08,0,0.0559242,0,0,-1.26e-05,0,0,-6.42e-17,0,0,4.02e-17,0. • UMT User Motion – Geodetic (MOTB command required) • 0 00:00:01,MOTB,10.00,10.00,200.0,4.471,0,79.875,-0.001,0,0,-4.20e-06,0,-1.27e-08,0,0.0559242,0,0,-1.26e-05,0,0,-6.42e-17,0,0,4.02e-17,0. • Time can be either [D H:M:S] format or Seconds (e.g. 12.10) Proprietary & Confidential—Page 43

  44. User Motion Data (cont.) • An example of a UMT file is shown below Body Ang Rate (XYZ) Time ECEF Position ECEF Velocity ECEF Acceleration ECEF Jerk Attitude (HEB) Proprietary & Confidential—Page 44

  45. User Motion Data (cont.) • The UMT file can easily be assigned to a vehicle for use in the scenario as shown below for Vehicle 1 • The user can just select the desired UMT file for simulated the vehicle motion • Note: The UMT file must be enabled, or “checked” in order for it to be used • All UMT files bypass any command and personality files • If multiple vehicles, then the user can have multiple UMT files, one for each vehicle Proprietary & Confidential—Page 45

  46. User Motion Data (cont.) • It is important that the user generated motion data simulates consistent motion dynamics, e.g. the position data cleanly differentiates up to jerk • A common cause for unexpected receiver performance (e.g. loss of satellites, problems tracking, inaccurate simulated inertial data) when using user generated motion data is the consistency of data • Specifically, the higher order derivatives (acceleration and jerk) must be consistent with the position and velocity data • This can be checked using the check_mot.exe utility in the SimGEN root folder • Inconsistent data can also cause GBLK or NBLK scaling errors observed in the Messages Window which can degrade performance • Additionally, using logged data from a flight or drive may introduce some unwanted effects of noise or “jumping” in position because of poor DOPs or multipath experienced during the logging • The simulated RF output is only as good as the data it is using to generate it Proprietary & Confidential—Page 46

  47. User Motion Data (cont.) • As mentioned earlier, User Motion data also supports the remote motion formats of MOT and MOTB • The user just has to rename the ASCII motion file to *.umt • These MOT/MOTB formats are described in the SimREMOTE User Manual • A MOT example (ECEF reference frame) is shown below 0 00:00:00.00,mot,v1_m1,6378137,0,0.000000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:00.10,mot,v1_m1,6378137,0,0.010000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:00.20,mot,v1_m1,6378137,0,0.020000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:00.30,mot,v1_m1,6378137,0,0.030000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:00.40,mot,v1_m1,6378137,0,0.040000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:00.50,mot,v1_m1,6378137,0,0.050000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:00.60,mot,v1_m1,6378137,0,0.060000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:00.70,mot,v1_m1,6378137,0,0.070000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:00.80,mot,v1_m1,6378137,0,0.080000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:00.90,mot,v1_m1,6378137,0,0.090000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:01.00,mot,v1_m1,6378137,0,0.100000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:01.10,mot,v1_m1,6378137,0,0.110000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:01.20,mot,v1_m1,6378137,0,0.120000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 0 00:00:01.30,mot,v1_m1,6378137,0,0.130000,0,0,0.1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 Proprietary & Confidential—Page 47

  48. Agenda • Controlling the desired satellite constellation • Defining vehicle types and motion • Using antenna patterns • Multiple vehicles and antennas

  49. Antennas Overview • In order to received the GPS signals from the satellites, the receiver requires an antenna • Supporting applications from cell phones to satellites, there are a variety of antenna types and configurations • Some variations are: • Antenna patterns which are different for each frequency in both Gain and Phase • The position on the platform or vehicle (e.g. Lever Arm) from where the center of navigation is to the antenna • Different bandwidth for receiving various operating signals such as L1, both L1 and L2, GLONASS, L5, Galileo, etc. • Thus, the unit under test (UUT) antenna configuration varies from one platform to the next with different impacts on the performance of the GPS receiver during testing • So antenna patterns can enhance the fidelity and confidence of the test results http://www.sanav.com/ Proprietary & Confidential—Page 49

  50. Modeling Antennas in SimGEN • In the real world, the antenna is offset from the receiver and designed for certain frequencies with both unique gain and phase patterns • SimGEN supports integrating all of these antenna system characteristics for the vehicle in the simulation as shown below • Lever arms from the antenna to the receiver are supported in SimGEN’s Antenna > Options > Offsets file • Ability to track various signals is available through SimGEN’s Antenna > Signal Types • Antenna patterns are available for different frequencies and for gain (level) and phase under the Antenna > Antenna Pattern Control Proprietary & Confidential—Page 50

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