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About RF Cafe
1996 - 2022
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...
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Note: Many answers contain passages quoted in whole or in part from the text.
This 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 improve reception
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)
c) Moving 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 interference nonstationaries?
a) Unlimited theoretical sensitivity
b) Unlimited theoretical number of targets
c) They 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 tangential rhomboid
d) We say 'noise of color,' not 'colored noise'
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
d) The model-based method
9. For which case is the max SINR (signal-to-interference-plus-noise-ratio) beamformer statistically optimal?
a) Additive Gaussian interference
b) Coherent random clutter
c) Incoherent predictive clutter
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 be utilized
c) Slow-moving targets can be ignored
d) Fixed object like buildings can be cancelled out
Need some help? Click here for the answers and explanations.