taux de fausse alarme constant

OBS: taux prédéterminé pour permettre à un récepteur de recevoir des échos de fausses cibles sans les traiter comme échos de cibles réelles.

OBS: Constant False-alarm Rate (CFAR). A constant false-alarm rate in the presence of variable levels of noise is usually a requirement placed on any modern radar. It is easily achieved in CW radars by use of filter banks. The energy reaching the filter bank is restricted either by automatic gain control or, when feasible, by limiting, and the thresholds in the circuitry following the filter bank are properly set with respect to the level in the total band. In a typical setting technique, random noise is injected into the amplifier that drives the filter bank, and each threshold is set to achieve the desired false-alarm rate. The level of noise is then varied and the threshold rechecked. If the limiting is proper, the false-alarm rate should not change. However, target signals in the absence of noise are unaffected, as they do not change the total energy present in the broad doppler spectrum sufficiently to reach the limiting level.