All RF Cafe quizzes make great fodder
employment interviews for technicians or engineers - particularly those who are fresh
out of school or are relatively new to the work world. Come to think of it, they would
make equally excellent study material for the same persons who are going to be interviewed
for a job.
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RF Cafe Quizzes.
Note: Some material based on books have quoted passages.
quiz is based on the information presented in
Space-Time Adaptive Processing for Radar, by J. R. Guerci.
Note: Some of these books are available as prizes in the monthly
RF Cafe Giveaway
"Space-time adaptive processing (STAP) is an exciting technology for advanced radar systems that allows for significant
performance enhancements over conventional approaches. Based on a time-tested course taught in industry, government
and academia, this second edition reviews basic STAP concepts and methods, placing emphasis on implementation in
real-world systems. It addresses the needs of radar engineers who are seeking to apply effective STAP techniques
to their systems, and serves as an excellent reference for non-radar specialists with an interest in the signal
processing applications of STAP. "
1. What was the original application of Space-Time Adaptive Processing (STAP)?
a) Moving target indication (MTI) radar
b) The Strategic Defense Initiative (SDI, aka 'Star Wars')
c) Time travel
d) Atomic time standards
2. Why is moving target indication processing needed?
a) For better angle of arrival (AoA) determination
b) To enable detection of non-stationary objects
within a background of stationary objects
c) It satisfies DoD contract requirements
d) To cancel
out moving objects so stationary objects can be seen
3. What advantage does narrowband (c/B >> Nd) electromagnetic plane wave provide?
B = modulation bandwidth, N = number of elements, d = interelement spacing
a) Greater power efficiency
b) More planar than a non-planar wave
c) Tangential coordinates
d) Insures propagation across the array is manifested as a simple phase shift.
4. What are two key physical observables for MTI processing?
a) Aircraft and watercraft
b) Doppler frequency and angle of arrival (AoA)
fixed targets and fixed moving targets
d) Power and amplitude
5. What are ramifications on adaptive processing due to variability in clutter terrain and other
a) Unlimited theoretical sensitivity
b) Unlimited theoretical number of targets
place practical limits on the size and quality of training data available
d) All of the above
6. What mathematical form does 'colored' noise take?
a) A 2nd-degree polynomial
b) A nondiagonal covariance matrix
c) A complex hyperbolic
d) We say 'noise of color,' not 'colored noise'
What is "the iceberg effect" (see chart at right)?
a) Ground clutter provides a chilling effect on returns
b) Increase in interference rank with
increasing CNR due to realistic physical limitations
c) A phenomenon where ice degrades radar performance
d) High power radar melts ice exponentially with applied amplitude
8. What is another name for a structured-covariance method of STAP?
a) The covariance-structured method
b) The iceberg method
c) The Gureci method
The model-based method
9. For which case is the max SINR (signal-to-interference-plus-noise-ratio) beamformer statistically
a) Additive Gaussian interference
b) Coherent random clutter
c) Incoherent predictive
d) None of the above
10. What is a major advantage to radar clutter returns of having a prediction horizon on the
order of only seconds?
a) A significant degree of determination, and thus predictability
b) Slow-moving aircraft can
c) Slow-moving targets can be ignored
d) Fixed object like buildings can be cancelled
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