A Novel Model for Direction Finding and Phase Center With Practical Considerations

The data model for direction of arrival (DOA) estimation is revisited and studied with more attention to the practical implementation of the antenna arrays and verified through measurement results. A complete data model for a single-channel direction finding system that includes, for the first time, the effects of the switching mechanism among antennas is presented. In order to combat coupling among antenna elements and the radio frequency switch nonidealities, a comprehensive model is developed, which includes more accurate noise modeling. The effect of the phase center (PC) in DOA estimation is then discussed and an improved data model is presented, which includes the antenna's PC movement. The Cramer-Rao bound for circular arrays including the newly introduced parameter for the PC is derived. The new model shows significant improvement in the estimation accuracy.