rf channel simulators add hardware-in- the-loop test capability to stk steve williams, rt logic...
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RF Channel Simulators add Hardware-in-the-Loop Test Capability to STK
Steve Williams, RT [email protected], 719-598-2801
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RF Channel Simulation
Whenever a transmitter and receiver are in motion with respect to one another, flight and ground COMMS systems must be tested against many conditions, both nominal and worst-case:
Carrier and Signal Doppler Shift
Delay Losses Noise Interference
Intentional Unintentional
Terrain & overhead obscuration
Natural and man-made atmospheric conditions
Flight paths, orbits, ground paths, ground locations
Transmitter characteristics Receiver characteristics Antenna patterns Etc…
True for: satellites, UAVs, aircraft, missiles, targets, ships, rockets, ground vehicles, ground locations, etc.
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RF Channel Simulation
STK provides superb simulation, analysis, reporting and visualization tools
STK provides easy-to-use scenario creation and modification tools
STK provides a solid physics engine
Results in high confidence that the COMMS system should work.
At some point though, hardware-in-the-loop testing must occur with the actual COMMS systems devices.
This is not a departure from STK, but rather a hardware add-on to it.
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Example: Adaptive Coding and Modulation (ACM) Modem Test
ACM Satellite Modem (or
components) under test
ACM Satellite Modem (or
components) under test
Ethernet Ethernet
Tx Rx Tx Rx
May include in-band ACM control
signals
May include in-band ACM control
signals
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Satellite Replaced by Channel Simulator
ACM Satellite Modem (or
components) under test
ACM Satellite Modem (or
components) under test
Ethernet Ethernet
Tx Rx Tx Rx
RF Channel
Simulator
STK Scenario Point-to-PointAdvanced COMMS Transmitter Characteristics Receiver Characteristics Antenna Patterns Interference Losses Etc.
May include in-band ACM control
signals
May include in-band ACM control
signals
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STK Control of the Channel Simulator
ACM Satellite Modem (or
components) under test
ACM Satellite Modem (or
components) under test
Ethernet Ethernet
Tx Rx Tx Rx
STK Scenario
Ethernet
STKSpreadsheets - user created - from STK reportsUser ProgramsGUI
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Role of the Channel Simulator
Create or perturb RF/IF signals to match a particular scenario. Fully physics-compliant Phase-continuous
Especially important for phase shift keying modulation (BPSK, QPSK, etc.)
Real-time High-resolution interpolation
(~18.7ns)
Doppler Shift
Delay
Path Loss
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Role of the Channel Simulator
Satellite passes are a fairly simple channel simulator task.
A missile flying on a test range, for example, is quite different.
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Example: Testing the Test Range
AmplifierTelemetry
Tracking Site Equipment
STKScenario
TelemetryData
Channel Simulator
Amplifier
AmplifierTelemetry
Tracking Site Equipment
Channel Simulator
Amplifier
AmplifierTelemetry
Tracking Site Equipment
Channel Simulator
Amplifier
RangeControlCenter
BSS
Displays
Space Launch Ranges Missile & Weapons Test Ranges Aircraft Test Ranges Etc.
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Example: Testing with On-orbit Assets
On-orbitGEO SatelliteTo-be-launched
LEO Satellite
Simulated LEO-to-GEO signals Signal carrying response of
GEO to simulated LEO signals
Inter-satellite links Aircraft / Satellite links Satellite / Ground links Etc.
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Other uses
Almost any situation where transmitters and receivers will be in motion
StimulusSignals
ReceivedSignals
System Response
Analysis tools, systems and processes to determine that Received Signals and/or System
Response was appropriate based on the Stimulus Signals provided.
RF orIF
RF orIF
ReceiverSystem or
Component Under Test
TransmitterSystem or
Component Under Test
FlightProfile
Channel Simulator
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Role of the Channel Simulator
The Channel Simulator performs complex tasks, but must be very easy to use.
Keep users focused on the problems they are trying to solve, not how to make the instrument work.
STK Control Spreadsheet Control
Can be fed by STK Reports GUI Control
May contain STK elements in the future, via STK Engine User-program Control
TCP/IP ASCII/Binary Commands Synchronized to real-time events
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Channel Simulator STK9 PlugIn Implementation
Comms Systems, receivers, transmitters, sensors and antennas may be included.
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Summary
STK is a advanced modeling, simulation and visualization package based on a solid physics engine foundation.
The Channel Simulator is a sophisticated RF instrument that adds high-accuracy, physics-compliant carrier and signal Doppler shift, delay, attenuation, noise and interference to test signals for a wide variety of applications.
Together, the combined solution is powerful, easy-to-use, flexible, cost-effective and unique.
For further information– Steve Williams, RT Logic, Colorado Springs, CO.– [email protected], 719-337-8103– www.rtlogic.com/t400cs