Beam-space Processing Of Broad-band Multiple Beam Antenna Data For Source Localization
M.W. Hoffman, K.M. Buckley · 2005
This paper considers using an MBA, along with high resolution spatial spectrum estimation procedures, to estimate locations of broad-band EHF sources. In particular, spatial spectrum estimation with a one meter continuous aperture MBA is investigated, assuming a ten percent bandwidth centered at 44 GHz. Observed source rank, computed via a broad-band model of the MBA, is calculated over a range of locations. While the numerical rank (i.e., the number of dimensions required to represent a given fraction of source energy) of these observations can be greater than one, narrow-band processing for spatial spectrum estimation is shown to be sufficient for applications within the ten percent fractional bandwidth and a reasonable (25 dB for our case) dynamic range of source power. A consequence of the high ratio between the Ist and 2nd largest eigenvalues of the observation is that further focusing of a broad-band MBA source is unlikely to increase system performance. We suggest that usual narrow-band techniques for determination of the number of sources and signal subspace dimension (i.e., AIC or MDL on eigenvalues) should not be used. Finally, when a large dynamic range of sources is expected, broad-band processing will be required.