METHOD OF MEASURING FLIGHT ALTITUDE OF AIRCRAFT AT LOW AND ULTRALOW ALTITUDES DURING APPROACH LANDING Russian patent published in 2015 - IPC G01S13/94 

FIELD: radio engineering, communication.

SUBSTANCE: method includes receiving a signal of a ground-based transceiver reflected from an aircraft and frequency-shifted due to Doppler shift; measuring the time when the Doppler frequency shift f_d reaches a set value and the time when the Doppler frequency shift reaches a value which is an inverse of the set value (-f_d); determining the time interval Δt between said measurements and calculating the flight altitude of the aircraft at low and ultralow altitudes during approach landing using the formula The value of the angleφ, formed by the velocity direction vector of the aircraft and the direction of the beam from the aircraft to the transceiver, is determined using the formula where λ is radiation wavelength, f_d is Doppler frequency shift, V is aircraft velocity.

EFFECT: high accuracy of measuring altitude during approach landing.

3 cl, 3 dwg