EVALUATION OF RADIO SOURCE’S COORDINATES BASED ON SOLUTION OF LINEARIZED SYSTEM OF EQUATIONS BY RANGE-DIFFERENCE METHOD

Grin' Il'ya Vladimirovich, Undergraduate student, Nizhny Novgorod State University named after N. I. Lobachevsky (23 Gagarina avenue, Nizhny Novgorod, Russia), yelowt@mail.ru
Ershov Roman Aleksandrovich, Postgraduate student, Nizhny Novgorod State University named after N. I. Lobachevsky (23 Gagarina avenue, Nizhny Novgorod, Russia), yelowt@mail.ru
Morozov Oleg Aleksandrovich, Doctor of physical and mathematical sciences, professor, sub-department of information technologies in physical research, Nizhny Novgorod State University named after N. I. Lobachevsky (23 Gagarina avenue, Nizhny Novgorod, Russia), oa_morozov@nifti.unn.ru
Fidel'man Vladimir Romanovich, Doctor of engineering sciences, professor, head of sub-department of information technologies in physical research, Nizhny Novgorod State University named after N. I. Lobachevsky (23 Gagarina avenue, Nizhny Novgorod, Russia), fidelman@nifti.unn.ru

621.396

Background. One of the most common methods for determining the coordinates of a radio source in passive systems of positioning is the range-difference method. As a navigation parameter the range-difference method uses the difference of distances from the source to the spaced synchronized receivers determined by mutual time delay of the received signals. Determination of the radio source’s coordinates is based on solving a system of nonlinear equations, and requires significant computational costs. The field of application of the range-difference method is associated with the need to measure the navigational parameters under changing frequency characteristics of the received signals due to the influence of the Doppler Effect arising during the signal propagation in satellite systems, and under low signal-tonoise ratio, which significantly increases the computational complexity of the problem to be solved. The main purpose is to enhance the computational efficiency of the algorithm of determining the radio source’s coordinates by the range-difference method, which is achieved by initial assessment of coordinates obtained from the solution of the linearized system of equations and by using a computationally efficient algorithm for determining the mutual time delay of the received signals in the presence of the Doppler shift of signals under a low signal-to-noise ratio.
Materials and methods. The results presented in this paper were obtained by computer simulation of signal processing in the passive satellite system of radio source positioning on the general-purpose processor (CPU), and using parallelization of computations on the GPUs.
Results. The authors developed an algorithm for radio source positioning, using an initial estimate of the source’s coordinates based on the solution of the linearized equations of the range-difference method to be aaplied in a satellite positioning system. The characteristics of the proposed algorithm were also investigated.
Conclusions. It is shown that the use of the proposed approach has achieved significant performance gains in calculation of radio source’s coordinates. An important feature of the proposed algorithm is that it can be used for detecting and determining the location of radio sources in real time.

range-difference method, mutual time delay, determination of coordinates.

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