Resolving more sources with multi-frequency coarrays in high-resolution direction-of-arrival estimation

This paper presents a multi-frequency method to increase the number of incoherent sources that can be resolved using multiple signal classification (MUSIC). The method uses coarray equivalence to construct a ldquovirtual correlation matrixrdquo with a higher dimension than the number of receiving elements. This allows for more sources to be resolved than with traditional MUSIC, where the number of sources must be less than the number of receiving elements. This method will prove to be useful in situations where the number of antenna elements must be limited, but there are many sources. The method as presented here has restrictions on the types of sources that can be resolved.