IEEE - Aerospace and Electronic Systems - August 2022 - 54

Interview With Professor Yaakov Bar-Shalom
time on publishing papers. " A famous professor from MIT
who spent his summers in the Bay Area consulting for SCI,
got the job of assessing if I was wasting company time. His
recommendation that the work I did " makes sense " savedme
from being fired. The most notable compliment I received
from him was that a year after this, he published a paper
based on the PDAF idea-with appropriate acknowledgment
to me. The journal publication of the PDAF almost did not
happen-the division manager thought it would be useful for
a proposal, which never happened-I had to wait until the
division manager was on vacation and then got the VP's permissiontopublishitinajournal.
Important
discussions with Robert Lynch.
patible with the filter calculated covariances) and how not
to design one. (One of the problems in my 2001 Wiley
book on estimation has a story about a " young Turk " preoccupied
with the issue of filter consistency.)
Peter: Speaking of your time at SCI, that is, when you
invented the PDAF. What was the background for that
invention, did you see the present practice as wrong and in
need of fixing? And how was the PDAF received by your
company and the community? [It might be good to give a
short technical description of the PDAF so that nontracking
readers understand.]
Yaakov: The PDAF came about when it became clear that
data association for tracking needed a solid mathematical
method-though not optimal, it worked quite well and it is in
use to this day in numerous systems. The PDAF was a simple
application of the total probability theorem: each measurement
in the " validation region " of a target received a probability
of being the correct one (as opposed to clutter) and
these measurements together with their association probabilities
were then used in a suitably modified tracking filter. As
an aside, I was almost fired because of " wasting company
Peter: At UConn, you have graduated many Ph.D. students.
Do you have any who were particularly memorable?
Yaakov: I had the honor and privilege of graduating 42
Ph.D.s (some as co-major advisors with colleagues with
whom I have extensive and friendly cooperation), with a
few more in the pipeline, and 6 Ph.D.s as (effectively)
their major advisor at other universities. Out of these, 18
are currently professors at various universities.
Peter: You have had a huge and productive career and have
developed many things. I would say that you stand out as a
person whose research has actually made a difference in the
world ... It is not just a nice theory, but it gets built. Can you
talk a little about some of your contributions ... the most
impactful ones, and also those ofwhich you are most proud?
Yaakov: There are several that I am aware of(and perhaps
many more that I am not cleared to see).
1) Defense Science and Technology Organization in Australia
implemented the PDAF in the Jindalee over the
horizon radar and this was a key factor inmaking the systemwork
in spite ofthe heavy false alarm (clutter) rate.
2) Raytheon (Bedford/Marlborough, MA, USA) implemented
a joint probabilistic data association tracker
for their airport surface detection equipment, Xband,
relocatable over the horizon radar, groundbased
radar prototype for national missile defense,
and in the theater high altitude antiballistic defense.
The latter saw action in the Middle East (unlike me).
3) The image feature (target centroid) extraction and
tracking algorithm have been implemented in the
ARROW ABM (Antiballistic Missile) cosponsored
by Ballistic Missile Defense Organization. This system
has reached operational capability.
Yaakov with two of his favorite companions: his Beneteau sailboat
and a good single-malt Scotch. Francesco Palmieri and Peter
Willett are also in the picture.
54
4) ETC (Mystic, CT, USA) implemented the IMMPDAFAI
(Interacting Multiple Model Probabilistic Data
Association Filter with Amplitude Information) algorithm
for tracking a low signal-to-noise ratio (SNR)
maneuvering target with an active sonar using the target
amplitude information. This has been transitioned
to the USN Fleet (System 53).
IEEE A&E SYSTEMS MAGAZINE
AUGUST 2022
IEEE - Aerospace and Electronic Systems - August 2022

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