METHOD OF MEASURING ELEVATION ANGLE OF AERIAL OBJECT IN METER RANGE OF ELECTROMAGNETIC WAVES USING ELECTRONIC MAP OF AREA Russian patent published in 2020 - IPC G01S3/74 G01S13/72 

FIELD: radar ranging.

SUBSTANCE: invention relates to the field of radar ranging, specifically to the method of measuring elevation angle (EA) of an aerial object (AO) in a meter band of electromagnetic waves using a vertical antenna array (AA). Method of measuring elevation angle AO consists in receiving, with the help of vertical N-channel AA, direct and reflected from the underlying surface of the Earth, presumed AA radio signals AO, real signals and an array of their quadratures. Before receiving real signals, forming an array of model signals which take into account the dimensions of AA, the surface of its assumption, data of digital map of area, amplitude and phase Fresnel coefficients, which depend on angle of incident wave and reflected from Earth. Model arrays are normalized by amplitude and phase. Then, direct and reflected real signals are received and normalized in N channels of receiving elevation AA. Simultaneously with amplitude normalization of real signals, their phase normalization is performed relative to phase of signal of specified element AA. Further, the normalized real signal is compared with the calculated normalized values of the model signal. Further, normalized model arrays are compared to normalized real signal received by AA. Results of signals comparison are sums of squares of "discrepancies" δx_m, δy_m, δA_m by x- and y-quadratures and A-amplitudes respectively. Further, a non-linear spectral function R_m is constructed according to the rule R_m=1/δx_m+1/δy_m+1/δA_m, then the maximum value of spectrum R_max is found on the massif R_m, its position M_max on an angular coordinate and a decision is made on the measured elevation angle G_AO according to the rule G_AO=d·M_max, where d is the received size of the discrete step of measurements by the elevation angle.

EFFECT: high accuracy of measuring angular coordinates of low-altitude AO in "their insensitivity zone θ" at elevation angles comparable to the width of the beam pattern of the receiving elevation AA.

1 cl, 6 dwg