Catalog maintenance of low-earth-orbit satellites: Principles of the algorithm

In Russia, the main source of information on orbital and ballistic characteristics of manufactured Earth satellites is the catalog of these objects maintained by the Space Surveillance System. Maintenance of this catalog is performed in real time by a complex automatic system, which includes a network of sensors and software tools for processing acquired data in automatic and interactive modes. The general structure and characteristics of this system for low-Earth-orbit satellites were first reported in February 1992 in Moscow at the conference on space debris and were published in 1993 [Khutorovsky, Z, N., "Satellite Catalog Maintenance:" Space Studies, Vol. 31, No. 4, 1993, pp. 104-114 (translated from Russian)]. In continuation of that publication, the issues of the design of the system of software tools for automatic catalog maintenance are considered. Statistical decision theory is the basis for the synthesis of this system (complex algorithm), Analysis of the informational efficiency of this algorithm under real conditions is performed. It is demonstrated that the algorithm comprises two major components: primary determination of orbits and tracking. These are two continuous processes permanently interacting with each other. The character of this interaction is determined by the time-spatial pattern describing situations when the special "informativity" condition for the measurements is disturbed, A very general outline of these processes, following from the theory, is defined. Then the implemented algorithms for primary orbit determination and tracking are described. The methods of statistical decision theory under conditions of various types of a priori uncertainty are used in the synthesis of these procedures.