| Interferometric imaging (aperture synthesis imaging) is a technique used
by radio astronomers to achieve angular resolution that far surpasses what is
possible with a single large aperture. A similar technique has been used
for radar imaging studies of equatorial ionospheric phenomena at the
Jicamarca Radio Observatory.
We present plans for adding an interferometric imaging capability to the
EISCAT Svalbard Radar (ESR), a capability which will contribute
significantly to several areas of active research, including naturally and
artificially enhanced ion-acoustic echoes and their detailed relation
in space and time to optical phenomena, polar mesospheric summer
echoes (PMSE), and meteor studies.
Interferometry using the two antennas of the ESR has demonstrated
the existence of extremely narrow, field-aligned scattering structures,
but having only a single baseline is a severe limitation for
such studies.
Building additional IS-class antennas at the ESR is not a trivial task.
However, the very high scattering levels in enhanced ion-acoustic echoes
and PMSE means that a passive receiver antenna of more modest gain should
still be capable of detecting these echoes.
In this paper we present
simulations of what an imaging interferometer will be capable of
observing for different antenna configurations and brightness
distributions, under ideal conditions, using two different image inversion
algorithms. We also discuss different antenna and
receiver technologies. |