Co-site interference analysis - CST · CST – COMPUTER SIMULATION TECHNOLOGY | Co-site...

CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com

Co-site interference analysis

Marli Strydom CST AG

CST – COMPUTER SIMULATION TECHNOLOGY | www.cst.com

The Cosite Scenario Victim Rx trying to “hear” desired signal from remote Tx At the same time, local emitters are transmitting Emitters can interfere with desired signal reception

= Cosite Interference

Undesired Emitters Victim Rx

Desired Signal

THE GOAL: predict the potential for cosite interference

for all Rx’s in the scenario.


Multiple RF systems co-located in a common environment Diverse system characteristics

Frequency bands (10 KHz to 40+ GHz) Power levels Modulation types

Multiple EMI coupling paths Antenna coupling Cable coupling Circuit coupling

The Co-Site Problem


Mechanisms for Cosite Interference There are many mechanisms for coupling

between the Tx’s and the Rx: Antennas Cables Enclosures Conducted vs. Radiated

Coupling can be direct between a Tx and Rx…

Or it can be more complex… Or even devious! (e.g., rusty bolt effect) Non-linear interactions generate additional

spectral components (Intermodulation)

Emitter signal spectra contain both narrowband (NB) and broadband (BB) signal components

Signals in-band and out-of-band must be considered


Many methods to achieve EMC Antenna placement, type Decreased transmit power levels Adding filters Replacing defective hardware Frequency planning

The Conceptual Solution: Cosite EMI


Availability of input data – varying types and fidelities Cosite evaluation usually cannot wait on high-fidelity system data Data management and cosite models must allow incremental refinements Result post-processing is critical for identifying and mitigating cosite EMI

problems.

Predicting Cosite EMI The biggest challenge in making useful cosite EMI predictions lies in managing all of the input data, models, output data, and results.


EMIT

EMIT provides an approach to data management and simulation for cosite EMI predictions.


Antenna models Aircraft geometry (CAD) RF component models Radio emissions and

susceptibility models

Inputs for an EMIT Analysis


Co-Site Interference Workflow

Antenna synthesis Antenna coupling Co-site EMI


Predator Co-Site Analysis

UHF blade 320 MHz

VHF blade 30-100 MHz

GPS elliptical patch 1.575 GHz

IFF2 monopole 1020-1100 MHz

IFF1 monopole 1020-1100 MHz


Broadband Multi-Port Coupling


Installed Patterns

60 MHz 320 MHz 1.06 GHz 1.06 GHz 1.575 GHz


Delcross EMIT Co-Site Tool Tx Emissions

Rx Vulnerability Component Characteristics

Antenna Coupling

Software framework for managing system performance data,

simulating intra-system EMI effects and mitigating EMI issues


Emit is a system management tool Multi-fidelity quality inputs can be used EMI prediction can start at early level of project As input fidelity increases, so do the EMI prediction

Conclusion


Multi-Fidelity Coupling Models

Constant Coupling - constant Path Loss - free-space path loss

(distance) Path Loss + Gain - computed from the

path loss and the antenna gain in the direction between antennas.

S-Parameters - wideband coupling from user-supplied S-parameters (from measurements or CST STUDIO SUITE)

(dB

)

Fixed Value

Path Loss

Path Loss & GainS-Parameters


EMIT Library EMIT Library currently provides multiple models of

‘typical’ radios of interest to military and commercial users

Each model is notated with specific details of the system

Representative models for outboard components are also provided

The Library content will continue to be enhanced and updated

Users can create and maintain their own databases of systems and components in custom libraries

Libraries can be exported for sharing with other users

Date post:	03-Apr-2018
Category:	Documents
Upload:	duongdang
View:	237 times
Download:	8 times

Co-site interference analysis - CST · CST – COMPUTER SIMULATION TECHNOLOGY | Co-site...

Documents