Comparison of two options for building three-coordinate electronic intelligence stations

Abstract

The subject–coordinate measurement methods in ground electronic intelligence (ELINT) stations. The goal is to conduct a comparative analysis of two options for the composition ground ELINT stations in terms of accuracy of measuring coordinate information. The tasks to be solved are as follows: assessing the accuracy of determining the coordinates of the time difference of arrival method (TDOAМ) and hybrid method (HM); obtaining analytical ratios for estimating the root-mean-square error (RMSE) of the accuracy of measuring the altitude of radio emission sources (RES) of these methods; on the basis of the obtained estimates and analytical ratios, a comparative analysis of the methods, under conditions where the accuracy of the coordinate information obtained by both methods is commensurate; and development of recommendations regarding the practical application of HM coordinate measurements. The methods used are: the theory of measurements and the theory of evaluation of coordinate information. The following results were obtained: a comparative analysis of the TDOAМ and HM was performed according to the RMSE of the determination of plane coordinates and the altitude of the RES. The accuracy assessment was performed in a known way, based on the linearization of the functional dependence between the measured primary parameters (range differences, elevation angle) and spatial coordinates by expanding in a Taylor series with the deduction of the first two terms of the series. Calculations have shown that the presence of the third side station has very little effect on the accuracy of determining plane coordinates. Significant differences appear only in the results of estimating the RMSE of the RES altitude. To compare the methods, analytical relationships were obtained for estimating the RMSE of the altitude measurement. The condition is determined under which the accuracy of determining the altitude for the HM is not worse than that for the TDOAМ (the accuracy is the same). Starting from this value and further, when using the HM, the altitude is determined more accurately. Conclusions. An HM of high-precision determination of 3 coordinates in ELINT stations, based on measuring two distance differences and direction finding (DF) in the elevation plane, can, with a smaller number of side stations (two instead of three), provide accuracy no worse than the known TDOAM. However, this requires that the RMSE value for DF in elevation should be tenths of degrees. The practical application of HM is possible for the issuance of target designations on air defense missile systems radar.