METHOD OF DETECTING SIGNALS WITH CONSTANT FALSE ALARM LEVEL Russian patent published in 2011 - IPC G01S7/36 

FIELD: physics.

SUBSTANCE: in the n-th scanning space, a radar set processes a received mixture of signals and noise, which includes through-period compensation for noise from local objects. The envelope curve of the mixture of signals and noise is picked up, where the said mixture contains noise residues from local objects. Readings of the envelope curve are formed. Data on the power of the noise residues from local objects stored in memory is used in range readings where j is the number of the reading. A threshold level U_k is formed. The square of the envelope curve in the k-th range reading is compared with the threshold level U_k. A decision is made on the presence of a target signal in the k-th range reading when the condition is satisfied. To determine the threshold level U_k after formation of readings of the envelope curve, a range window is formed from N_w readings of the square of the envelope curve lying symmetrically about the k-th range reading inspected for presence of a target signal, where noise power in the range window is determined using a certain formula. If said noise power estimate in the range window exceeds the given power of noise residues from uniform local objects then features for detecting transient noise interference are formed, during presence of which overshooting of the power of noise residues from local objects is estimated in the said k-th range reading over the power of the noise residues from uniform local objects using the corresponding formula. The ratio of the estimate of the overshooting of the power of noise residue from local objects in the k-th range reading over the power of noise residues from uniform local objects to the estimate of noise power in the range window : is determined. The threshold level U_k is found using the formula: where C(γ) is a threshold coefficient which is selected such that a given false alarm probability value is ensured at the given value.

EFFECT: high stability of the probability of false alarm in conditions of a mixture of noise from local objects which is not uniform over range and is not completely suppressed and transient noise interference from external sources.

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