ALGORITHM FOR CALCULATING DIRECTIONS TO A RADIO SOURCE 

Vladimir A. Maklashоv, Postgraduate student, Samara National Research University named after academician S. P. Korolev (34 Moskovskoye highway, Samara, Russia), E-mail: kipres@ssau.ru
Rustam M. Mirzoev, Postgraduate student, Samara National Research University named after academician S. P. Korolev (34 Moskovskoye highway, Samara, Russia), E-mail: kipres@ssau.ru 

621.396 

10.21685/2307-4205-2021-1-7 

Background. The passive method of direction finding does not allow measuring the range to a radio emission source (RES) using the classical single-position method. One of the ways to solve this problem is to use multi-position direction finding stations. However, at the same time, difficulties arise in determining the coordinates of the RES, due to the following features of the method: direction finding stations are located on aircraft (AC), and RES – on the earth's surface; on board the aircraft it is possible to place only linear antenna arrays, which make it possible to determine by the phase method the bearing of the RES in only one (horizontal) plane. The difference in the heights of the location of the object and the RES leads to errors direction finding measurements, which reduces the accuracy of determining the coordinates of the RES. With the practical use of this method and the construction of equipment, these features must be met. For this, it is necessary to introduce algorithms for correction, compensation, and maneuver to reduce the influence of the angle of sight of the RES on the accuracy of direction finding. The purpose of this work is to reduce the errors in determining the direction finding and coordinates of the RES.
Materials and methods. A direction finding correction algorithm is proposed. Simulation of target location is carried out. Estimates of the error in determining the bearing and position of the RES. The influence of altitude on the direction finding error is determined.
To obtain the coordinates of the target, the "Target Location" algorithm was used. This takes into account the additional phase incursion. A bearing correction algorithm has been developed, which is based on the triangulation method. Simulation was carried out in the MATLAB environment.
Results. Modeling the correction algorithm on a test model made it possible to reduce the bearing determination error from 4.9 to 0.1 degrees. The azimuth error to the target has decreased from 15 to 0.3 degrees. The position determination error decreased from 3 km to several tens of meters. 
Conclusions. The consistency of the correction algorithm was proved by modeling. As a result of the simulation, it was found that the error in determining the bearing and coordinates of the RES using the correction algorithm is reduced by about 50 times. The data obtained make it possible to develop functional software for electronic warfare (EW) systems. 

algorithm, direction finding, radio emission source, mathematical modeling, calculation, efficiency