Laser anemometry probe system and method employing continuous coherent detection, with single-particle mode, capable of detecting ice-forming conditions and of determining the severity of icing

Aircraft equipped with a laser anemometry probe (LAP) system employing continuous coherent detection, with single-particle mode, comprising:

• means (AN) for analysing the measurement signals of the said probe (LAP);
• means (MES_T) for measuring a temperature (T);
• characterized in that the LAP comprises, furthermore:
• first means (COMP1) for comparing a first discrepancy, over a duration of observation of the said measurement signals, between the phase of the signal measured by the said probe (LAP) and an expected phase, the expected phase being estimated on the basis of values of parameters characteristic of the laser beam emitted by the said probe, corresponding to the transit of a spherical particle, with a first threshold (S1) of phase discrepancy;
• second means (COMP2) for comparing a second discrepancy, over the said duration of observation of the said measurement signals, between the amplitude of the signal measured by the said probe (LAP) and an expected amplitude, the expected amplitude being estimated as a function of values of parameters characteristic of a laser beam emitted by the said probe, corresponding to the transit of said spherical particle, with a second threshold (S2) of amplitude discrepancy;
• third means (COMP3) for comparing the said temperature (T) with a third threshold (S3) of temperature;
• means (DET_GEL) for detecting the presence of a liquid water drop when the said first discrepancy is below the said first threshold (S1) and the said second discrepancy is below the said second threshold (S2);
• and
• means (DET_CG) for determining icing conditions when the said means (DET_GEL) for detecting the presence of a liquid water drop detect the presence of a liquid water drop, and when the said temperature (T) is below the said third threshold (S3).

Method of laser anemometry by probe (LAP) employing continuous coherent detection, with single-particle mode, in which:

• measurement signals of the said probe (LAP) are analysed;
• the temperature (T) is measured;
• characterized in that:
• a first discrepancy, over a duration of observation of the said measurement signals, between the phase of the signal measured by the said probe (LAP) and an expected phase, the expected phase being estimated on the basis of values of parameters characteristic of the laser beam emitted by the said probe, corresponding to the transit of a spherical particle, is compared with a first threshold (S1) of phase discrepancy;
• a second discrepancy, over the said duration of observation of the said measurement signals, between the amplitude of the signal measured by the said probe (LAP) and an expected amplitude, the expected amplitude being estimated as a function of values of parameters characteristic of a laser beam emitted by the said probe, corresponding to the transit of said spherical particle, is compared with a second threshold (S2) of amplitude discrepancy;
• the said temperature (T) is compared with a third threshold (S3) of temperature;
• the presence of a liquid water drop is detected when the said first discrepancy is below the said first threshold (S1) and the said second discrepancy is below the said second threshold (S2);
• and
• icing conditions are determined when the said detection of the presence of a liquid water drop detect the presence of a liquid water drop, and when the said temperature (T) is below the said third threshold (S3).