Abstract.
The
article discusses the issue of determining the area essential for the
reflection of radio signals in the bistatic location of the Moon using two
radars, one of which is on Earth, the other on the lunar orbital spacecraft.
Based on the Fresnel approximation, the region of greatest reflection is
defined as a portion of the surface whose center is found from the condition of
equality of angles between the normal to the surface and the directions from
this point to the receiver and transmitter. The radius of the reflection area
is associated with the Fresnel zones, and it is believed that the reflection
from the first zone makes the greatest contribution to the reflected signal,
however, both practice and numerical simulation show that a surface
significantly exceeding 3-4 Fresnel zones is involved in the formation of the
reflected signal. The linear dimensions of the reflection area also depend to a
small extent on the ruggedness of the relief of the study area. Consequently,
when preparing experiments, predicting and interpreting measurement results, it
is necessary to involve a digital 3-D model of the lunar surface. The article
presents the derivation of formulas for determining the surface area boundary,
which makes the greatest contribution to the formation of the reflected signal.
Coordinates can be determined in real time mode by the height, longitude and
latitude of the spacecraft.
Key words: bistatic radar, coordinates, reflected spot, the Moon,
spacecraft.
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