Features of measuring three-dimensional coordinates and velocity vector of air objects within coverage of overall range-finding facilities for diversity reception

Abstract

The features of managing radar coverage formed by overall range-finding systems for diversity reception that measure longitude, latitude and altitude, including those of low-flying air objects using broadband phase-code manipulated (PCM) signals are considered. The named coordinates are defined by Newton's method, which finds solution to the system of three transcendental equations binding unknown coordinates of objects with measured overall ranges from transmitter to object and from object to each of the receivers.

Dependences for estimation accuracy of altitude on true flight altitude of objects are given for signal bandwidth of 10 or 20 MHz and for three or six receivers of radar range cells. Possibility of measuring three-dimensional velocity vector of air object is analyzed by solving a system of nonlinear equations binding the sum of projections of object's velocity vector to directions from transmitter to object and from object to each receiver with measured Doppler frequencies in local Cartesian coordinate system. Besides, operating features of overall range-finding algorithm for diversity reception involving multipath signal reflected from air object are examined. Output performance of the analyzed three-coordinate overall range-finding system is estimated by comparing it with a two-coordinate single radar. It is demonstrated that increasing pulse train, decreasing scanned area, increasing wavelength and decreasing noise ratio does not only make up for a significant drop in directivity factor of isotropic transceiver antennas in overall range-finding system, but also enables to reduce significantly transmitter power or target scattering cross-section.