Radio interferometric network for
Experimental radiointerferometric network was created with the purpose of providing independent continuous orbital support to the future Ukrainian geostationary telecommunication satellite (GTS) "Lybid". The network can be used to monitor the technological maneuvers of GTS, to detect the facts of its collision with space debris, to clarify a model of moving objects in geostationary orbits.
The basic principle of network operation is the use of passive radar method and correlation analysis to calculate TDOA (Time Difference Of Arrival) using signals of digital satellite television. The network synchronously receives these signals that are compliant with the standard of DVB-S (Digital Video Broadcasting-Satellite). Orbital position of satellite is determined by using measured values of the TDOA and station coordinates. To calculate the perturbed orbit of GTS, the network must consist of four or more stations.
Today, the network consists of five stations spaced out and located in:
- Institute of Radio Astronomy of the National Academy of Sciences of Ukraine (Kharkiv);
- Western Center of Radio Engineering Surveillance (Mukacheve);
- Rivne Minor Academy of Sciences of School Age Youth (Rivne);
- Ventspils University College (Ventspils, Latvia).
The orbital elements of a tracked satellite are determined by diurnal arrays of measured values of TDOA using the analytical model SGP4/SDP4 and the numerical model of integrating the satellite equations, given in the left and right columns of table, respectively. The numerical model takes into account the perturbations caused by the gravitational attraction of the Moon, the Sun and the nonspherical Earth. Note that the error of the numerical model is 5.4 times less than the error of the analytical model. Elements of the orbit received for one day are contained in three lines, numbered from zero. Zero row contains the same information in the left and right columns, namely:
Δτ = τi - τk ,