FIRST RESULTS OF CLARIFYING OF ORBITAL ELEMENTS OF LOW-ORBIT SPACECRAFT USING OBSERVATIONS OF THE RI "MAO" DOPPLER STATION

Анотація

18 artificial satellites of the Earth, which
emit radio signal at a frequency of 430-440 MHz during their
flight in the Mykolaiv visibility zone, were found as a result
of the searching carried out in the RI "MAO". 10 of 18 satel-
lites during not less than 7 days each were automatically
tracked by the Doppler station created in the RI “MAO”. The
frequency of received radio signal was automatically deter-
mined as a result of spectral processing of radio signal ampli-
tudes registered by the station during satellite tracking.
Herewith 5 of 10 satellites emitted non-harmonic broadband
signals. The radial velocity of satellites is calculated using the
frequency of received radio signals.
The obtained values of radial velocity changing in time
were used to clarify TLE (Two-Line Element) orbital el-
ements of satellites. Initial orbital elements were down-
loaded from the space-track.org site. It would be noted
that model values of Doppler shift of frequency, obtained
using the initial orbital elements, also use for searching
radio signals emitted by tracked satellites and received by
the station. The regular (mean) and random (standard de-
viation) components of the difference (O-C) of measured
and model values of radial velocity were calculated. A
comparison of the regular and random components of O-C
was made, which showed their slight decreasing after clar-
ifying orbital elements.
In order to improve the accuracy of the orbit determination,
it is proposed to upgrade the station's hardware and software in
order to reduce synchronizing and frequency determination
errors. It is also proposed to use more accurate models as Dop-
pler measurements, and the motion of satellite