Patent ID: 7477192

Claim:
A direction finding system for determining the direction of arrival at a particular location of signals received by a plurality of antennas that are arrayed in a known pattern in relation to the particular location, the system comprising: means for coding signals provided by at least some of the plurality of arrayed antennas in response to receipt of the signals within a predetermined band of frequencies; means for combining coded signals from different sets of less than all of the plurality of arrayed antennas to provide an analog combined signal; means for down-converting the frequency band of the analog combined signal; means for converting the down-converted analog combined signal to a digital signal representative of the combined coded signals; means for processing the digital signal to derive signals from the plurality of signals respectively provided by the different sets of less than all of the plurality of arrayed antennas; signal processing means for processing the derived signals to determine the directions of arrival of the signals that are received by each set of antennas; and means for selecting the different sets of antennas from which the received signals are provided for said coding and combination; wherein the signal processing means include: (a) means for processing the derived signals individually to estimate the directions of arrival of signals within said predetermined band of frequencies received by the respective antennas of each set; (b) means for processing derived signals for which a direction of arrival is estimated by the (a) means to estimate the magnitudes of the signals received by each of the different sets of antennas at different frequencies within the predetermined band of frequencies; and (c) means for processing the estimated directions of arrival and the estimated magnitudes of the signals received by the different sets of antennas to determine the directions of arrival of signals received by the antennas at said different frequencies.