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Multi-Spectral Scene Generation Workshop Redstone Technical Test Center. PST: A Distributed Real-Time Architecture for Physics-based Simulation and Hyper-Spectral Scene Generation. Michael John Muuss U. S. Army Research Laboratory Maximo Lorenzo U. S. Army CECOM. Why We Model.

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Multi-Spectral Scene Generation Workshop

Redstone Technical Test Center

PST: A Distributed Real-Time Architecture for Physics-based Simulation and Hyper-Spectral Scene Generation

Michael John Muuss

U. S. Army Research Laboratory

Maximo Lorenzo

U. S. Army CECOM

why we model
Why We Model
  • We are predicting or matching physical phenomena:
    • Damage statistics of live-fire tests.
    • Energy levels received by a sensor.
  • Hollywood storytellers communicate feelings to people. “Skin-deep” models are fine for them.
current future challenges for t e
Current & FutureChallenges for T&E
  • In simulation, re-creating the real-world:
    • Re-creating individual engineering tests.
      • S&E community starts here.
    • Re-creating real proving grounds.
    • Re-creating training centers and training exercises.
    • Re-creating combat locations and scenarios.
      • Training community & wargamers start here.
meeting the simulation challenge
Meeting the Simulation Challenge
  • Engineering-level geometric detail.
  • Physics-based simulation.
  • Realistic 3-D atmosphere, ground, and sea models.
  • Fast: Real-time, near-real-time, Web, and offline.
    • Hardware-in-the-loop, man-in-the-loop.
  • Common geometry.
  • Common software.
  • Massively parallel processing.
what is pst
What is PST?
  • PST = PTN and SWISS, Together!
    • PTN = Paint-the-Night
      • Real-time polygon rendering
      • From CECOM NVESD
    • SWISS = Synthetic Wide-band Imaging Spectra-photometer and Environmental Simulation
      • Ray-traced BRL-CAD™ CSG geometry
      • From ARL/SLAD
paint the night
Paint-the-Night
  • 8-12 micron IR image generator.
  • SGI Performer based.
  • Uses outboard image processor for sensor effects.
  • A large highly tuned monolithic application
    • With exceptionally high performance.
    • Highest polygon rates seen on a real application.
  • Individually drawn trees (2 perpendicular polygons)
  • Individually drawn boulders.
swiss
SWISS
  • A physics-based synthetic wide-band imaging spectrophotometer
    • A camera-like sensor
    • Looks at any frequency of energy.
  • A set of physics-based virtual worlds for it to look at:
    • Atmosphere, clouds, smoke, targets, trees, vegetation, high-resolution terrain.
  • A dynamic world; everything moves & changes.
advantages of a ray tracing sig
Advantages of a Ray-Tracing SIG
  • Allows reflection, refraction:
    • Windshields, glints.
    • Branch reflections, 3-5.
  • Atmospheric attenuation, scattering.
    • Individual path integrals.
  • Accurate shadows:
    • Haze, clouds, smoke.
  • Multiple light sources:
    • Sunlight, flare, spotlight.

2nd-Generation FLIR image

(Downsampled to 1/4 NTSC)

csg rendering advantages
CSG Rendering Advantages
  • Ray-traced CSG is free from limitations of hardware polygon rendering:
    • No approximate polygonal geometry.
      • No seams, exact curvatures.
    • Exact profile edges. Important for ATR!
    • No level-of-detail switching, no “popping”.
    • Full temperature range in Kelvins, not 0-255.
    • Unlimited spectral resolution, not just 3 channels.
cruise missile shadow
Cruise Missile Shadow

Ridge Profile

Missile Shadow

Terrain Quantization

a grand challenge computing problem
A Grand-ChallengeComputing Problem
  • Real targets, enormous scene complexity, > 10Km2.
  • Physics-based hyper-spectral image generation.
  • Nano-atmospherics, smoke, and obscurants.
  • Ray-traced image generation, exact CSG geometry.
    • Near-real-time (6fps).
  • Fully scalable algorithms.
  • Network distributed MIMD parallel HPC.
  • Image delivery to desktop via ATM networks.
target geometry complexity
Target Geometry Complexity
  • Need at least 1cm resolvable features on targets.
complex geometry today
Complex Geometry Today
  • < 1cm target features.
  • 1m terrain fence-post spacing
  • Three-dimensional trees:
    • Leaves.
    • Bark.
  • Procedural grass, other ground-cover.
  • Boulders, other clutter.

Current

Developmental

one geometry multiple uses
One Geometry,Multiple Uses
  • To compute ballistic penetration & vulnerability:
    • Need 3-D solid geometry and material information.
  • The same targets are also useful for:
    • Signatures: Radar, MMW, IR, X-ray, etc.
    • Smoke & Obscurants simulation.
    • Chem./Bio agent infiltration.
    • Electro-Magnetic Interference.
ray traced atmosphere
Ray-Traced Atmosphere
  • Propagation easy in vacuum!
  • Modeling four effects:
    • Absorption
    • Emission
    • In-scatter
    • Out-scatter
  • Computer can’t do integrals.
    • Repeated summation
    • Discretized atmosphere
sources of volumetric atmospheric data
Sources of Volumetric Atmospheric Data
  • Need gas-density(x,y,z) for each gas species.
  • Sources:
    • Predictive: Nano-meteorology model.
    • Re-enactment: input from measurements.
      • E.g. Smoke-week data.
    • Statistical: noise, FBM, fractals.
      • Generates data with specified statistics.
pst implementation goals
PST Implementation Goals
  • To have a software backplane:
    • Allowing each function to run as separate process.
    • Allowing easy reconfiguration.
    • Allowing independent software development.
    • Using common geometry throughout.
    • Multiple Synthetic Image Generator (SIG) types.
      • Keep simulation details out of the SIGs.
a basic pst simulation
A Basic PST Simulation

Entity

Controllers

World

Simulations

Sensor

Simulation

Output

Transducers

Input

Transducers

Textures

Solar

Load

Gen

Atmosphere

PTN

SIG

ToD

Mapper

Ground Therm

Met

Tree Therm

Data-cube

Magic

Carpet

Target Therm

MFS3

HW

Mapper

Sensor

Controller

Monitor

Vehicle

Controller

Vehicle

Dynamics

FlyBox

Mapper

Intersect

Process

DB

Vehicle

Dynamics

MODSAF

MODSAF

I/F

independent time scales
Independent Time Scales
  • Image generators need to run fast:
    • 30 Hz for humans.
    • 6 Hz is fastest acquisition rate of ATRs.
    • 800 Hz for non-imaging sensors (Stinger rosette).
  • Physics-based simulations can run slower:
    • 90 sec/update for thermal & atmosphere models.
  • Transient effects need to be added as a delta:
    • Leaf flutter, explosions, smoke details.
hardware environment
Hardware Environment
  • Multiple CPUs per cabinet.
  • Multiple cabinets linked via OC-3 or OC-12 ATM.
    • Geographically distributed (Belvoir, APG, Knox).
  • Multi-vendor system, e.g.:
    • Cray vector machine for thermal mesh solution.
    • SGI Origin 2000 for parallel ray-tracing.
    • SGI Infinite Reality for polygon rendering.
  • 100-200 processors participating.
backplane philosophy

BRL-CAD™

Ray Tracer

Backplane Philosophy
  • Standardized Slots (Interface).
  • Location independent
    • Except for performance.

V/L Server

Vehicle

Dynamics

Paint-the-Night

Polygon Renderer

Paint-the-Night

Polygon Renderer

Terrain

HLA with enhancements

Thermal Models

:

:

pst implementation plan
PST Implementation Plan
  • Attempt to implement PST using HLA.
    • Concern over real-time performance.
    • No support for bulk data transfer.
  • Fall back on JMASS, TARDEC, or home-brew.
hla features
HLA Features

Publishandsubscribe to objectsandinteractions

Federate a

Federate b

Federate f

HLA

Federation

Federate c

Federate e

Federate d

required backplane features
Required Backplane Features
  • Event Services
    • Implement with HLA interactions.
  • Query/Response Services
    • HLA interactions with custom routing space.
  • Continuous/Bulk Data
    • Custom Distributed Shared Memory software.
      • Auto-broadcast, optional subscriber notification.
      • Notification, subscriber polls for data update.
hla ping
HLA Ping
  • Tool to measure communications delay.
    • Patterned after Muuss’s TCP/IP ping tool.
  • Special ping client federate.
  • Common ping server interaction in all federates.
  • Uses federate_id routing space for efficiency.
  • Measurements:
    • Round-trip (interaction pair).
    • Half-trip (if both federates in same cabinet).
hla ping diagram
HLA Ping Diagram

?

?

Ping Client

Federate

RTI

RTI

Request Packet

Ping Target

Federate

?

?

Reply Packet

pst fom basics
PST FOM Basics
  • ECEF coordinates, 64-bit IEEE double precision.
  • Using Quaternions to represent orientation.
  • Entity motion always sent in motion_t:
    • Position, velocity, acceleration,
    • Orientation, Orientation dot, Orientation dot dot.
    • Facilitates dead-reckoning in SIGs, simulations.
  • Point-of-View interaction: motion_t & “handle” obj.
    • Moving POV stays attached to moving entity.
vpg demonstration
VPG Demonstration

Terrain

Server

Driver

MGED

HLA

Tcl / Tk

Tcl / Tk

Tcl / Tk

User

geometry database
Geometry Database
  • A superset collection. Each entity will have:
    • The original BRL-CADTM CSG model.
    • Polygonal models at various LoD.
    • Optical and thermal textures.
    • Iconic representations: e.g. burning, destroyed.
    • Nodal decomposition for input to thermal solvers.
    • Articulation graph
    • Definition of damage-state vector.
two hla wrappers
Two HLA Wrappers
  • Muuss strategy: Hide all HLA and XDR inside C++ “send” and “receive” methods.
    • One C++ object for each HLA interaction & object.
    • Simulations need little HLA, C++ objects need lots.
  • Baldwin strategy: Build total-insulation library.
    • C++ objects know nothing about HLA.
    • But XDR becomes very difficult.
working testbed
Working Testbed

Flybox

Mapper

Vehicle

Dynamics

Controller

SGI-Performer

Image Generator

FlyBox

Ping Client

Monitor

facilitating the god gui
Facilitating the“GOD GUI”
  • We desire the ability to reach into a running simulation and “force” parameters.
    • E.g. teleport a vehicle, heat some ground...
  • Use HLA object ownership, or one multi-cast application-layer interaction?
    • Object ownership uses 8+ network transmissions.
application of pst
Application of PST
  • The image generator is just one component of a larger simulation. E.g. MFS3, or missile simulation.

Full Platform Simulation

or HWIL

Full Platform Simulation

or HWIL

Full Environment Simulation

PST

6 DoF

Flight Dynamics

ATR

Images

Motion_t

Control Decisions

ft knox application of pst

DTV

DTV

DTV

DTV

Ft. Knox Applicationof PST
  • 1 RT SIG, 3 SGI SIGs, soldiers-in-the-loop.

Digital Video to ATM

ATM to D-2 Video

PST

PTN

Mapper

RT

DREN

ATM

Mapper

Mapper

PTN

Mapper

PTN

DREN ATM

who is this muuss fellow anyway

Who is this MUUSS Fellow, Anyway?

Mike Muuss

Señor Scientist

U.S. Army Research Laboratory

APG, MD 21005-5068 U.S.A.

<Mike@ARL.MIL>

http://ftp.arl.mil/~mike/