Array processing: Difference between revisions

Revision as of 12:08, 31 January 2016

Revision as of 06:06, 7 June 2016

Line 164:

Since <math>\mathbf{a}</math> is generally not known, <math>\mathbf{P}_a^{\perp}</math> can be constructed using the eigen-decomposition of <math>\mathbf{R}</math>, in particular the matrix containing an orthonormal basis of the noise subspace, which is the orthogonal complement of <math>\mathbf{a}</math>. The disadvantages to this approach include altering the visibilities covariance matrix and coloring the white noise term.<ref>{{cite journal

| author author1= Jamil Raza, |author2=Albert-Jan Boonstra, |author3=Alle-Jan van der Veen | date = February 2002

| date = February 2002

| title = Spatial Filtering of RF Interference in Radio Astronomy

| journal = IEEE Signal Processing Letters

Line 183 ⟶ 182:

This approach requires much more computationally intensive matrix manipulations, and again the visibilities covariance matrix is altered.<ref>{{cite journal

| author author1= Amir Leshem, |author2=Alle-Jan van der Veen | date = August 16, 2000

| date = August 16, 2000

| title = Radio astronomical imaging in the presence of strong radio interference

| journal = IEEE Transactions on Information Theory

Line 203 ⟶ 201:

where <math>\lambda_1(2 \alpha - \alpha^2) \approx \sigma_s^2</math> by selecting the appropriate <math>\alpha</math>. This scheme requires an accurate estimation of the interference term, but does not alter the noise or sources term.<ref>{{cite journal

| author author1= Amir Leshem, |author2=Albert-Jan Boonstra, |author3=Alle-Jan van der Veen | date = November 2000

| date = November 2000

| title = Multichannel Interference Mitigation Techniques in Radio Astronomy

| journal = Astrophysical Journal Supplement Series