Pg 1 of xx AGI Modeling GPS Adaptive Nulling Receivers Ken Sherman (Satellite Software), Haroon...
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Transcript of Pg 1 of xx AGI Modeling GPS Adaptive Nulling Receivers Ken Sherman (Satellite Software), Haroon...
Pg 1 of xxAGI www.agiuc.com
Modeling GPS Adaptive Nulling Receivers
Ken Sherman (Satellite Software),
Haroon Rashid (AGI), Trevor Stief (AGI)
Pg 2 of xxAGI www.agiuc.com
Satellite Software
• AGI business partner specializing in antennas
• Develops antenna modeling software (SATSOFT)
• Developing a series of antenna plug-ins for stk & ntk
• www.satsoft.com
• Contact Ken Sherman (sales at satsoft dot com)
Pg 3 of xxAGI www.agiuc.com
Overview
• Plug-In Architecture
• Array Design
• PA GUI
• Nulling Algorithms
• Null Formation
• Scenarios
• Results
• Future Work
• Conclusions
Pg 4 of xxAGI www.agiuc.com
Antenna Plug-In Architecture
stk GUI Panel
2D/3D Contours
Link Analysis &
Reports
Receivers, Transmitters & Jammers
Plug-In GUI
Antenna Geometry
Analysis & Pattern
Computation
Antenna Beamformer
Pattern Contours
Pattern Cuts
STK
Plug-In
Pg 5 of xxAGI www.agiuc.com
Wide Range of Antennas Supported by Plug-In
• Active & passive receiving antennas
• Active & passive transmitting antennas
• Beam steering and nulling
• Arbitrary polarization (LP, CP, etc)
Pg 6 of xxAGI www.agiuc.com
Active Receiving Antenna
L1 L2 LrF1, G1
Lossless Antenna
Equivalent Active Antenna Receiver
01
1201101 )1()1()1( t
g
lltlftlte
0
1t
tf ee
2
1
l
ggckt
1
,,
l
gg losslessa
Pg 7 of xxAGI www.agiuc.com
Features of Phased Array Plug In
• Quickly design arrays for any receiver or transmitter in stk & ntk
• Planar, linear, and cylindrical (conformal) array geometries
• Circular, elliptical, and polygonal apertures
• Shaped beam phase and/or amplitude synthesis
• Adaptive nulling
• Taylor circular, rectangular, and Baylis low sidelobe aperture tapers
• Several element models
• Linear & circular polarization
Pg 8 of xxAGI www.agiuc.com
Designing & Analyze the Array
Define:
• Size & shape of aperture
• Number & position of elements
• Type of radiating elements
• Nulling algorithm, if any
Perform:
• Static pattern analysis
Pg 9 of xxAGI www.agiuc.com
Phased Array User Interface
Pg 10 of xxAGI www.agiuc.com
Adaptive Nulling Algorithms
• LMS steepest descent
• Howells-Applebaum
• Sample Covariance Matrix Inversion
Pg 11 of xxAGI www.agiuc.com
Forming a Pattern Null
Pg 12 of xxAGI www.agiuc.com
STK Scenarios
• SATCOM Link with Jammer on Airplane
• GPS receiver with single jammer
Pg 13 of xxAGI www.agiuc.com
Un-Adapted Pattern
18.77
-1
-2
-3-5
-10
-20 -20
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-20
-20 -20
-20
-20
-20 -20 -30
-30
-30
-30
-30-30
-30
-30
-30
-30
-30
Pg 14 of xxAGI www.agiuc.com
Adapted Pattern
16.85
-1-2
-3
-5
-10
-10
-20-20
-20
-20
-20
-20-20-20-20
-20
-20
-20 -30-30
-30
-30-30
-30
-30
-30
-30-30
-30
-30
-30
-30-30
Jammer
Pg 15 of xxAGI www.agiuc.com
3D Antenna Pattern
Pg 16 of xxAGI www.agiuc.com
Future Work
• Phased array digital beamformer
• Phased array interface to future stk/radar module
• Reflector model (physical optics)
• Wire antenna model (moment method)
• Scripting (nulling algorithms, etc)
Pg 17 of xxAGI www.agiuc.com
Conclusions
• Flexible antenna plug-in architecture for stk & ntk
• New phased array plug-in under development
• Improvement of s/n by nulling a jammer
• Future work
Challenges:
• Accurate gain = pattern integration = cpu time
• Providing visual feedback
• Easy-to-use but comprehensive GUI