I was recently watching a documentary series on technological progress..
It reminded me of when I spent time investigating some ideas that were once considered cutting edge.
One such idea was something I spent a lot of time on; identifying aircraft using narrow beam radar.
This was over 40 years ago. Nobody had lasers back then.
Computers had not yet taken over so much of our world. Artificial Intelligence was still to be created.
Back in the days of the Viet Nam War i had been a fully qualified Air Intercept Controller.
The return signal from potential air attackers was not strong in those days. I would often use IFF
(Identification, Friend or Foe) returns to enhance target returns and positively separate the interceptor
I was controlling from the target he was to take on. Using IFF was a way of doubling the amount of energy
being received. An IFF inquiry pulse train triggered an automatic response from my interceptor. The power
broadcast was attenuated as it traveled through the air. Using radar meant the energy I transmitted would
have a weak echo when it bounced back to my radar receiver. Signal loss was reduced by the square of the distance.
Using IFF cut the distance the signal traveled in half.
But IFF had a vulnerability. If the enemy knew the frequency your IFF transponder worked on, he could extend
his detection range on your craft by transmitting his own IFF interrogation signal to trigger your response.
His IFF operated on a different frequency. The 2 IFF signals didn’t interfere with one another.
What we needed was a way to positively identify an air target without using IFF.
The concept I investigated use a very very narrow radar beam. It scanned the target and returned a signal that
could be mapped to show the outline of the target. That outline would then be compared to three dimensional
views of potential hostile aircraft. The views had to rotated through three axes until a match was found.
The idea actually worked. But it had some weaknesses of its own. Computer speed for comparing the outlines
was much too slow to allow for a rapid identification. There was also a complication caused by many countries
operating the same aircraft types, and the external appearance of aircraft from several countries also began to
look very much alike. Radar might tell you what kind of an airplane you had detected, but it couldn’t tell you who it belonged to. At the time, those considerations were enough to kill the project.
Wetherhorn 