A fundamental aspect of RADAR is that the time for using the information acquired through it does not allow any alternative validation. This means that the reliability of the information is based on the technical ability of dominating the physical phenomenon. Even when, for example, infrared sensors are used, man controls only the phase of setting or calibration, after which he can only rely on each signal; the following phase of control, made for instance by supervisors, looks more like an operative rather than an exploratory action. The system is designed taking into consideration a margin of error (an object is signaled as it was present but it’s not) or lack of signal (the object is present but radar does not detect it); the consequences of a mistaken acquisition of information must be accepted and taken into account.

I am highlighting one aspect of radar that will then be extended to other more complex systems: the control of results cannot be made by a human operator, and the action foreseen as a consequence of the information acquired cannot be prevented from happening. That means, the reliability of results is not controlled through an ex post test, but depends on our sheer ability of designing the artificial system properly. Many of us will certainly remember war movies where pilots of fighter-interceptors seem to be spending their time waiting lazily to be called to action, but, as soon as radar gives warning signals of enemy bombers, pilots get immediately on their planes and take off. There is no time to control information: fighters must gain altitude very quickly in order to fight bombers before they reach the right distance to release their bombs. The intrigue has not yet ended, though, because the radar engineer cannot give any assurances and there will always be a possibility that signals were false, that it was a false alarm and that pilots action was useless. But that is always better than the lack of signal, which means that bombs will fall on our heads totally unexpected. The engineer tries to balance these two possibilities, lack of signal and false alarm, because, as it is in life, they represent a contrast inside the project.

The attitude of trusting a project is not new within the fields of technology and engineering: when an airplane takes off, we believe that the engines’ power together with the plane’s lift will cause take off. But this is still a field where results are expected according to a deterministic approach: if there is no fault, the plane will take off. As for radar, on the contrary, the equipment can work properly even though an error might occur. The same thing applies to clinical tests in the health sector, where results often lead to false positives or false negatives.

It is indeed a fight between two cultures: the ex ante against the ex post approach, the culture of project against the culture of action, which is feasible only afterwards, after detecting an error or an infraction.

(Gabriele Falciasecca)

 

RADAR or Radio Detecting And Ranging is the detection of obstacles based on the effects produced by the reflection of waves emitted on purpose (a phenomenon which is also present in nature - see dolphins and bats).

entry Radar in the Treccani Encyclopedia

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