Aerospace and Electronic Systems Magazine September 2017 - 45

Wicks and Baldygo

Figure 5.

AFRL Sensors Directorate SPEAR test bed.

aided (KA) algorithms for filtering, detection, and track processing; databases and "knowledge sources" to aid in the understanding
of the environment; sources of measured and simulated datasets to
be used in research, assessment, and demonstration; metrics tools
for assessing performance; and visualization of results [16]. Second, building on the first key area, he sought to demonstrate performance enhancements to the E-8 JSTARS using KA techniques,
analogous to the E-3 AWACS results demonstrated a decade earlier.
The SPEAR test bed (Signal Processing Evaluation, Analysis,
and Research) was built and is illustrated in Figure 5 [17]. The
humble and simple beginnings of the Expert System CFAR processor in 1984 gave rise to an entirely new way of approaching sensor signal and data processing. As shown in the figure, numerous
innovations and over two decades of development were brought
together in this test bed-filtering, especially STAP, detection,
and track algorithms; modeling and simulation (M&S) tools; data
sets (simulated and measured); knowledge sources; and tools for
measures of performance (MOPS). The contributions of Mr. Todd
Cushman and Mr. Mark Novak from AFRL and Mr. Walter Szczepanski, Mr. Robert Bozek, and Mr. Jeff Tyler of Black River Systems Company were critical in implementing the SPEAR test bed.
An important aspect of the aforementioned MOPS tool is the linkage it created between signal and data processing enhancements,
typically reported in terms such as test statistics, PDF, SINR, SINR
loss, or Pd, and Pfa, and corresponding tracking and exploitation
metrics more commonly employed and understood by Air Force
users and operators. The ability to "translate" and articulate signal
processing enhancements in terms more readily interpreted by operators was a major factor in transitioning Expert System CFAR
SEPTEMBER 2017

and subsequent KA signal and data processing technology to the
Air Force and the rest of the user community. Concurrently, Mr.
Jon Jones of AFRL's Information Directorate was very influential
in shaping the MOPS tool, elevating track processing, and especially raising data exploitation technology to a much higher level
of sophistication and acceptance by the user community.
The SPEAR test bed enabled a series of performance assessments to be conducted, including Expert System CFAR for
JSTARS, as well as various configurations of KA processing for
Global Hawk and other candidate transition platforms. Performance improvements using Expert System CFAR were indeed
demonstrated for JSTARS using real-world measured data in heterogeneous clutter environments (mountains/desert) with several
slowly moving, closely spaced ground targets (analysis and demonstration of results presented to and lauded by the 2002 US Air

Figure 6.

Expert System CFAR and technology development timeline.

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Table of Contents for the Digital Edition of Aerospace and Electronic Systems Magazine September 2017