channel simulators to test rf communication links for ... · channel simulators to test rf...

Colorado Springs, CO (719) 598-2801 Denver, CO (303) 703-3834 http://www.rtlogic.com

RT Logic, Steve Williams47th Annual Targets, UAVs and Range

Operations Symposium & Exhibition22 October, 2009

Channel Simulators to Test RF Communication Links for Targets,

UAVs and Ranges

222 October, 2009 swilliams@rtlogic.com

Whenever transmitters

and receivers are in motion with respect

to each other…

Receive Station Or System

• Special COMMS test needs exist…

– Doppler shift– Range delay– Range attenuation– Noise– Interference– Etc.

• When testing…– RF Hardware– Digital Hardware– Analog Hardware– Software– Firmware– Processes– Etc.

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Nominal conditionsWorst-case conditions

Initial development testsRegression testsCompliance testsStress tests

Dependent on flight path and ground locations.

• Strong need for thorough, economic and fast testing– Run often to detect problems as early as possible

• Doppler shift, delay, attenuation, noise and interference generation is difficult & time-consuming– Must know and understand flight paths– Must be physics-compliant– Must be phase-continuous, smooth, highly interpolated– Must have high resolution control and output

• Channel Simulators to the rescue– Create Doppler shift, delay, attenuation, noise and interference on test

signals

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TM Site

IF / RFCable / Radiated

IF / RFCable / Radiated

IF / RFCable / Radiated

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TM Site

Doppler shiftDelay

AttenuationNoise

Interference

IF / RFCable / Radiated

IF / RFCable / Radiated

IF / RFCable / Radiated

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• Channel Simulatorrequirements are non-trivial, but relatively straight-forward for SATCOM applications.

• Much higher complexities exist with more complicated motion relationships• Example: Targets,

UAVs and Ranges

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• Range vs. Time between a Vehicle Under Test (VUT ) and a TM site

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LEO Satellite Case UAV/Target/Aircraft Case

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• Key Channel Simulator Capabilities– Specs, phase-continuous and physics-compliant– Modular to accommodate multiple projects and test scenarios– Easily reconfigurable– Standard inputs / output– IF (cable), RF (cable), RF (near-field), RF (far-field)

• Signal Generator Capabilities– Multiple independent signals

• Modulation type• Data rate• Frequency offset• Amplitude• Etc.

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InsufficientChannelSpacing

Interference(Accidental orIntentional)

• Spectrum Analysis Capabilities– Spectrum, Constellation, Spectrogram– Modulation Analysis– Interference Analysis– Monitoring, Alarms

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22 October, 2009 swilliams@rtlogic.com13

TM Site

Doppler shiftDelay

AttenuationNoise

Interference

IF / RFCable / Radiated

IF / RFCable / Radiated

IF / RFCable / Radiated

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TM Site

Telemetry

Boeing Photo

TM Site

TM Site

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USAF Photo

TM Site

TM Site

TM Site

TM Site (Mobile)

TM Site

Mission Control Center:

Mission safety and best-source

telemetry

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TM Site #3

Doppler shiftDelay

AttenuationNoise

Interference

IF / RFCable / Radiated

IF / RFCable / Radiated

IF / RFCable / Radiated

Test Signal Source

PRN Data

ReplayArchived

Data

Other

TM Site #2

TM Site #1

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• Summary– Thorough and realistic tests, nominal and worst-case

– Flight COMMS systems– Ground COMMS systems– Ranges

– Key Values– Drives in quality– Improves system and mission assurance– Save time, saves cost, prevents over-design and under-design

– Additional Information– Steve Williams, RT Logic, swilliams@rtlogic.com, 719-598-2801– RT Logic Booth #05

RF HardwareDigital HardwareAnalog Hardware

SoftwareFirmwareProcesses