Assessing the NGSO GSO Systems Interference Levels using a COTS based Approach and Tool

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Assessing the NGSO / GSO Systems Interference
Levels using a COTS based Approach and Tool

• ITU BR Seminar - November 2000 - Geneva
• Prepared by TEUCHOS Group
• and
• Analytical Graphics Inc

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Content

• The EPFD Validation Tool
• Satellite Tool Kit Capabilities

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The EPFD Validation Tool

• Developped by TEUCHOS Group (France) under
  partnership with Analytical Graphics Inc (USA)

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Introduction

• Specifically designed to perform assessment of
  non-GSO satellite systems (NGSO)
  radio-communication interference levels on GSO
  satellite systems
• Checks their compliance with the "validation"
  limits specified by the International
  Telecommunication Union (ITU) Radio Regulations
• Follows ITU specifications of the JTG 4-9-11
  working group and the JWP 10-11S study group
• Uses ITU ApS4 data

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Interference configurations

• Allows computation and analysis of the Equivalent
  Power Flux Density (EPFD) generated by the
  non-GSO satellite system on the GSO satellite
  system.
• As specified by the ITU JTG 4-9-11, three types
  of EPFD are analysed

 uplink  Configuration
 Inter-Satellite  Configuration
 downlink  Configuration
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EPFD down

• Generated by the non GSO satellites at the GSO
  earth station
• EPFD down is defined as the sum of the power flux
  densities produced by at the GSO earth station by
  all the non GSO satellites

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EPFD up

• Generated by the non GSO earth stations at the
  GSO satellite
• Defined as the sum of the power flux densities
  produced at the GSO satellite by all the non GSO
  earth stations distributed in the GSO service area

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EPFD is

• Generated by the non GSO satellites at the GSO
  satellite
• Defined as the sum of the power flux densities
  produced at the GSO satellite by all the transmit
  non GSO satellites

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Key Features

• Input data coherent with ITU database.
• uses the following input data types.
• Common ITU database parameters
• Use of Power Flux Density (PFD) and Effective
  Isotropic Radiated Power (EIRP) masks

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PFD EIRP masks

• PFD masks defined an envelope of the power flux
  density radiated by the non GSO satellites
• EIRP masks defined an envelope of the effective
  isotropic radiated power generated by the non GSO
  satellites and earth stations

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Key Features

• Analytical capability
• includes complex algorithms capitalising on STK
  efficient and proven core capabilities allowing
  very fast computations .
• quickly and accurately calculate a satellite's
  position and attitude in time
• evaluate complex in-view and visibility
  relationships among satellites and ground
  stations,
• accurately compute EPFD figures in a short period
  of time.
• Computation time optimised to a very high level
  enhancing the productivity of the tool.

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Key Features

• Worst case definition of the GSO network
  location.
• geometrical worst case location of the GSO
  network identified.
• This worst case situation in term of interference
  when the probability to meet in line or quasi
  inline events is the highest.
• The EPFD Validation Tool performs this "Worst
  case definition of the GSO network location".

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Time step

• Simulation time increment is one of the most
  important parameters for determination of a
  distribution function of interference.
• It should guarentee absence of hight-level
  short-term interference missed
• EPFD tool includes algorithms for time step
  determination

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The tool

• Standalone add-onapplication basedon Satellite
  Tool Kit(STK ) corecapabilities
• Accurate, reliable and fast computations tool on
  PC-based platforms

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Tool Development Approach

• Development follows ITU JTG 4-9-11 (Joint Working
  Party 10-11S) specifications
• Development under a partnership with Analytical
  Graphics Inc (USA) and sponsorship of ESA .
• Approach reduces risks, and development time
  while maximising features and performance
• use of the leading COTS aerospace software as the
  core engine
• Satellite Tool Kit (STK)
• rapid prototyping
• accurate and fast computations usingSTK core
  engine
• use of STK Programming Library API
• Tests, and validation reduced

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Execution modes

• The EPFD Validation tool handles both execution
  modes
• a batch mode
• a GUI-based interactive mode,
• provides an intuitive and guided use of the tool
  through the use of wizards
• Execution status panel displays information
  throughout the execution of the software

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Intuitive GUI

• User is guided towards achieving its goals
• intuitive and easy to use no training required
• only necessary input data are used
• A Wizard-based approach

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Wizard panel 1

• Select the NGSOsystem with an inputfile
  containing ApS4 data
• PFD EIRP masks
• NGSOconstellation definition
• Select/define the output file

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Wizard panel 2

• Select theEPFDconfigurations
• Worst case
• Time step

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Wizard panel 3

• SelectNGSO systemrun parameters
• Select GSOsystem input data

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Wizard panel 4

• Select, validate,the S22 test cases
• all of
• some

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Computations

• All the S22 test cases selected are listed in an
  activity panel
• Computation progress displayed
• Access to the graphic and data reporting

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Graphic reporting
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Data reporting
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Summary

• Flexible, intuitive, accurate and fast
  computation tool designed for a PC-based computer
• Leverages STKs high-accuracy astrodynamics,
  communication and geometry models to provide an
  accurate, flexible environment for analysing
  interference levels produced by such NGSO systems
• Capitalises on efficient, validated and verified
  STK algorithms

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Try it - Contact us

• The EPFD validation tool is a freeware
• Ready to use now
• Download the Beta releasefrom www.stk.com
• Install it and ask foryour free EPFDvalidation
  tool license
• Contact us
• TEUCHOS Group Phone [phone]
• E-mail stk_at_teuchos.fr FAX 33
  (0)1.39.24.67.45
• or Analytical Graphics Inc Phone
  1-610-578-1000
• E-mail info_at_stk.com Fax [phone]

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Satellite Tool Kit Capabilities

• Analytical Graphics, Inc.
• 325 Technology Drive
• Malvern, PA 19355 (USA)
• Tel [phone] Fax [phone]
• WEB www.stk.com E-mail info_at_stk.com

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Introduction

• What is Satellite Tool Kit?
• What does STK do?
• STK family of products
• STK Communications Module
• Interference Analysis

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What is Satellite Tool Kit?

• STK is the leading Commercial-Off-The-Shelf
  (COTS) satellite systems analysis software.
• Collection of Powerful flexible Modules
• Promotes cross-discipline understanding of space
  issues
• Used by over 30,000 professionals world-wide
• Supports all phases of a satellite systems
  lifetime

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What Does STK Do?

• Extensive range of capabilities that allow you
  to
• Propagate satellite, aircraft, ship, ground site
  and vehicle positions in time
• Evaluate complex geometric relationships between
  all of these types of object s
• Determine the time one object can see or access
  another object
• Constraint access times based on complex
  relationships
• Perform analyses on operational objects, Comm.
  Systems, Radars
• Present results in graphical and text formats for
  easy interpretation analysis

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Key STK Capabilities

• Models all orbit types including LEOs, MEOs,
  HEOs, GEOs, Sun sync, and Deep Space.
• On-line database of over 9000 satellites and
  space objects
• No simplifying assumptions
• Validated and verified

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Who Uses STK?

• Everyone uses STK
• STK 4.2 is available from AGIs web site or by
  requesting a free CD.
• STK Professional version provides even more
  features functions
• Satellite systems professionals from all
  technical fields
• Evaluate the impact of key decisions quickly and
  easily
• Customers include
• Government
• Aerospace Contractors
• Satellite Operators
• Launch Services
• Research Organizations
• Universities

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AGI Family of Products

• Graphics
• Visualization Option (VO)
• High Res Maps
• VO-Earth Imagery
• Terrain
• Operations
• Close Approach Tool
• Navigator
• Precision Orbit Determination System
• Integration
• PL
• Connect
• DIS
• STKServer

• Orbit Analysis
• Long-term Orbit Predictor
• Lifetime
• High Precision Orbit Propagator
• Missile Flight Tool
• Dynamic Computational Analysis
• Chains
• Coverage
• Terrain
• Comm
• Radar
• GIS

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Comm Module

• Fully integrated into STK
• Models Comm. Objects with user controlled
  fidelity
• Able to model the quality of Comm. links and the
  parameters that affect it
• Provides link analysis for all orbit types (not
  just GEO) even Deep Space
• Generates contour plots of critical parameters

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Comm Module Brief Feature Outline

• ITU antenna Masks, Analytical, Aperture,
  circular, Rectangular, Multibeam antennas
• External user Data or ITU Gims
• Environmental Models
• Atmospheric absorption
• Crane and ITU rain models
• Sun, Earth, cosmic RFI
• Dynamic calculation of Noise temp.
• Dynamic Polarization loss calc
• Extended Modulation Source Coding types, also
  user defined
• Constrain access based on link performance
• How long can I maintain an Eb/No of 12 dB?

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Interference Analysis

• EPFD Down, EPFD Up and Inter Satellite
• STK performs interference analysis
• Dynamic geometric and Link relationships between
  objects
• User controlled constraints, e.g.
• Geostationary Belt exclusion
• Space Object Proximity Exclusion
• Model true interference levels based on actual
  link parameters
• ?T/T, C/I, C/(NI)
• power flux density
• Time Ordered or Statistical Analysis

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Comm Dynamic Graphics

• 3D Antenna Gain Beams
• 3D Antenna Body Axes Vectors
• 3D Antenna Polarization Axes Vectors
• Dynamic Interference Level
• Comm. Link Availability Quality
• Contours
• Antenna Gain, Eirp, Rip, Flux Density
• PFD Histograms

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Sample Comm Problems

• Im considering buying time on AsiaSat3. What
  effect will the inclination have on the EIRP
  pattern from the spot beam?
• What ground stations can I use and when to
  contact my satellite? I need to maintain a BER of
  10E-6.
• When will I have interference between my
  satellite and existing systems ( what level)?

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Coverage Analysis

• Fully integrated
• Available as a new Module
• Coverage Definition 13 Figure of Merits
• Thorough analysis of global or regional coverage
  by a single satellite or constellation of
  satellites
• Considers all constraints
• Compute accesses, Grid Inspector, Reports,
  Graphs, Static/Dynamic Contours Legend
• Worst case situations locations

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Sample Coverage Problems

• Assuming a failure of one satellite in my
  constellation, will gaps in coverage occur? If
  so, when and where will they occur?
• Given my large constellation of LEO
  communication satellites, how does the average
  number of simultaneously available satellites
  vary with latitude?
• Given a coverage area where are my best and
  worst receiver locations from interference point
  of view?

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STK Matlab Integration

• Fully integrated
• Access to full Matlab features graphics from
  STK
• Also Matlab script files have full access to STK
  features and calculation engine.
• STK can use models developed in Matlab for
  dynamic analysis.

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Summary
Work the problems, not the tools
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