B. V. Belik - Engineer, JSC «Concern «Vega», Student, MFTI
D. N. Suzanskii - Ph.D. (Eng.), Associate Professor, Head of Department, JSC «Concern «Vega»
V. S. Chernov - Ph.D. (Eng.), Associate Professor, Leading Research Scientist, JSC «Concern «Vega»

In the process of development of radio detection and location systems a lot of attention is paid to the choice of reasonable methods for determination of the coordinates and motion variables of targets. These methods are based on the analysis of radio emission from radio sources, which operate on board of these targets. However, target ranging and closing-in velocity measurement based on information of signal lag and Doppler shift is impossible, because time when signal was emitted and carrier frequency of emitted signal are unknown. In this case measurement of angular coordinates of radio sources located on the target could be the main source of information about the target-s location and speed. If this is the case, indirect methods of target-s range and its speed estimation are used, where signal receivers are spaced-apart. In this article pseudotriangulation method and method of "imaginary base" were analyzed and modified. The application conditions were defined for the case where vehicle trajectory is represented by two oppositely oriented parallel lines in a horizontal plane, linked by circular arc.