### ASA 126th Meeting Denver 1993 October 4-8

## 2aUW5. Predicting bistatic target scattering from monostatic data.

**Harry A. Schenck
**

**
**
*[Code 702S), RDT&E Div., Naval Command Control and Ocean Surveillance
Ctr., San Diego, CA 92152-7520]
*

*
*
Characterizing bistatic scattering from a target for many angles of
incidence is expensive and time consuming even in ideal laboratory conditions,
and essentially infeasible in an operational environment. Consequently,
extending the value of monostatic data by using it to estimate the bistatic
target strength is extremely desirable. Previous efforts to do this have severe
limitations or restrictions in their applicability. A new technique that
combines numerical modeling and experiment will be described. The crux of this
method is to rely on modeling to supply the far-field propagator function that
predicts the scattering in any direction when the surface values are known, and
to determine the surface values by least-squares approximation from knowledge
of the monostatic scattering and the principle of reciprocity which requires
the scattering matrix to be symmetric). An example will be shown in which the
complete three-dimensional scattering field was estimated for a rigid
axisymmetric body given only the monostatic target strength at angles in one
plane from 0 to 180 deg. Rules that relate the number of monostatic
observations needed to the frequency and the complexity of the target will be
described. The extension of this technique to nonrigid scatterers will be
discussed.