EFFICIENCY OF NEW METHODS FOR ESTIMATING ORBITS OF UNKNOWN NEAREARTH SPACE OBJECTS USING SHORT OPTICAL TRACKS OBTAINED OVER A FEW WEEKS INTERVAL

The work on a representative array of data demonstrates the capabilities of a new, essentially non‑linear algorithm for estimating the orbital parameters of near‑Earth space objects on several short optical tracks separated by long time pauses. The analysis of the work of the algorithm was carried out for five space objects moving in different orbits, including circular, high‑elliptical and low‑orbit with deceleration in the atmosphere and without it. When obtaining estimates of the parameters of the orbits, a priori information was not used. In all the experiments performed, including for very short tracks separated by a long pause in the observations, the minimum possible values of the quality criterion were achieved. The algorithm does not require large computing power – the calculation of the orbit on two tracks on a portable personal computer takes a split second.

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ALGORITHM FOR SELECTION OF LAUNCH ELEMENTS IN THE PRESENCE OF A PRIORI INFORMATION ABOUT ITS COMPOSITION AND STRUCTURE

Issues of radio electronics ◽

10.21778/2218-5453-2018-3-114-119 ◽

2018 ◽

pp. 114-119

Author(s):

O. I. Nemykin

Keyword(s):

Decision Making ◽

Loss Function ◽

Selection Process ◽

A Priori ◽

Measurement Information ◽

A Priori Information ◽

Space Objects ◽

Alternative Hypotheses ◽

Priori Information ◽

Selection Of

Traditional methods of the theory of statistical solutions are developed for cases of making single-valued two-alternative or multialternative solutions about the class of an object. Assuming the possibility of ambiguous multi-alternative (in the case of solving the problem of selection of space objects of three-alternative) decisions on the classification of of space objects at the stages of the selection process, a modification of the traditional statistical decision making algorithm is required. Such a modification of the algorithm can be carried out by appropriate selection of the loss function. In the framework of the Bayes approach, an additive loss function is proposed, the structure of which takes into account a priori information on the structure and composition of launch elements in relation to the classes «Launch vehicle» and «spacecraft». The algorithm of decision making is synthesized under the conditions of a priori certainty regarding the probabilistic description of the analyzed situation. It is shown that the problem of verifying three-alternative hypotheses can be reduced to an independent verification of three two-alternative hypotheses, which makes it possible to take particular solutions in the solution process and use a different set of the signs of selection for the formation of solutions for individual classes of space objects. The peculiarities of the implementation of the selection algorithm are discussed in the presence of a priori information and measurement information on starts of a limited volume. The synthesized Bayesian decision making algorithm has the properties necessary to solve the problem of selection of space objects at launch in real conditions in the presence of measuring information specified in the form of a training sample. Its architecture allows to form unambiguous and ambiguous decisions about each space object in the launch.

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CALIBRATION OF SENSOR CHANNEL DELAY UNCERTAINTIES FOR LINEAR MICROPHONE ARRAYS IN FAR FIELD

Journal of Circuits System and Computers ◽

10.1142/s021812669600042x ◽

1996 ◽

Vol 06 (06) ◽

pp. 607-618

Author(s):

MING ZHANG ◽

M.H. ER

Keyword(s):

Computer Simulations ◽

A Priori ◽

Microphone Arrays ◽

Far Field ◽

A Priori Information ◽

New Methods ◽

Sensor Channel ◽

Priori Information

In this paper, we present three new methods to calibrate the microphone channel delay uncertainties, and to estimate the talker location for linear microphone arrays in the far field. The proposed methods are based on different a priori information and can be applied to different cases, respectively. The proposed methods are simple and practical. The estimate errors are analytically derived and analyzed. Computer simulations and theoretical computations support the proposed methods.

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