Change of direction With the inexorable onset of
World War II, Bode turned his sights on the military applications of his control systems research, a change of direction that would last in varying degree to the end of his career. He came to the service of his country by working on the
Director Project at Bell Labs (funded by
National Defense Research Committee (NDRC) Section D-2), developing automatic
anti-aircraft control systems, whereby
radar information was used to provide data about the location of the enemy aircraft, which was then fed back to the anti-aircraft artillery
servomechanisms, enabling automatic, radar-augmented enemy aircraft
ballistic tracking, in other words, automatic shooting down of enemy aircraft with the help of radar. The servomotors used were both electrically and hydraulically powered, the latter being used mainly for positioning the heavy anti-aircraft guns.
Statistical analysis was also employed to aid in the computation of the exact position of the enemy aircraft and to smooth the data acquired from the target due to signal fluctuations and noise effects.
"Shotgun marriage" Bode therefore realized the first wireless data feedback loop in the history of automatic control systems by combining
wireless data communications, electrical computers, statistics principles and feedback control systems theory. He showed his dry sense of humour by calling this
multidisciplinary linkage a
shotgun marriage, referring to the
antiaircraft artillery origins of his historic invention, saying: "This, I said, was a sort of shotgun marriage forced upon us by the pressures of military problems in World War II." He also described it further as "a sort of 'shotgun marriage' between two incompatible personalities" and characterised the product of that linkage as a "son of shotgun marriage". The product of this "marriage", i.e. the automated artillery gun, can also be considered as a
robot weapon. Its function required to process data that was wirelessly transmitted to its sensors and make a decision based on the data received using its onboard computer about its output defined as its angular position and the timing of its firing mechanism. In this model we can see all the elements of later concepts such as
data processing,
automation,
artificial intelligence,
cybernetics,
robotics etc.
Working on director studies Bode, in addition, applied his extensive skills with feedback amplifiers to design the target data smoothing and position predictor networks of an improved model of director T-10, called the
director T-15. The work on director T-15 was undertaken under a new project at Bell Labs called
Fundamental Director Studies in cooperation with the NDRC under the directorship of Walter McNair. His NDRC-funded research at Bell Labs under the section D-2 (Control Systems section) contract eventually led to other important developments in related fields and laid the cornerstone for many present-day inventions. In the field of
control theory, for example, it aided in the further development of servomechanism design and control, a crucial component of modern
robotics. The development of wireless data communications theory by Bode led to later inventions such as mobile phones and
wireless networking. The reason for the new project was that director T-10 encountered difficulties in calculating the target velocity by differentiating the target position. Due to
discontinuities, variations and noise in the radar signal, the position
derivatives sometimes fluctuated wildly, and this caused erratic motion in the servomechanisms of the gun because their control signal was based on the value of the derivatives. In addition, the director T-15 operated only in rectangular coordinates, thus eliminating
coordinate-transformation-based errors. These design innovations paid performance dividends, and the director T-15 was twice as accurate as its predecessor and converged on a target twice as fast. the
operational amplifier based alternative of today's
digital computers. Inventions such as these, despite their military research origins, have had a profound and lasting impact in the civilian domain.
Military uses Anzio and Normandy The automated anti-aircraft guns that Bode helped develop were successfully used in numerous instances during the war. In February 1944, an automated fire control system based on the earlier version of the director T-15, called the director T-10 by Bell Labs or
director M-9 by the military, saw action for the first time in
Anzio, Italy, where it helped down over one hundred enemy aircraft. On
D-day 39 units were deployed in
Normandy to protect the
allied invading force against
Hitler's
Luftwaffe. Its flight specifications almost perfectly suited the target design criteria of director T-10, that of an aircraft flying straight and level at constant velocity, His work on electronic communications, especially on filter and equalizer design, continued during this time. In 1945 it culminated in the publication of his book under the title of
Network Analysis and Feedback Amplifier Design, which is considered a classic in the field of
electronic telecommunications and was extensively used as a textbook for many graduate programs at various universities, as well as for internal training courses at Bell Labs. He was also the prolific author of many research papers that were published in prestigious scientific and technical
journals. In 1948, President
Harry S. Truman awarded him the
President's Certificate of Merit, in recognition of his remarkable scientific contributions to the war effort and to the United States of America. ==Peacetime contributions==