Digital beamforming for an electronically scanned radar system

A method of digital beamforming in an electronically scanned radar system comprising:

• forming a predetermined number of antenna elements to transmit a received signal to a receiver;
• controlling the sensitivity of the antenna elements by performing a digital beamforming function in a digital beam former;
• forming a time multiplexed switch matrix to time the transmission of the received signal from the antenna elements to the receiver;
• and
• utilizing a Doppler function on the received signal prior to the digital beamforming function to manage a target motion induced phase shift across the antenna elements with the digital beam former, wherein utilizing the Doppler function comprises employing a Doppler frequency filter followed by a Doppler compensation function, the Doppler frequency filter to differentiate between a multiple number of the received signals, and the Doppler compensation function to compensate for the target motion induced phase shift for a center frequency of a particular Doppler frequency filter.

An electronically scanned radar system comprising:

• a predetermined number of antenna elements for transmitting a received signal to a receiver;
• an overlapped subarray feed network for receiving the received signals from the antenna elements, and for forming a predetermined phase center spacing to define a location of a grating lobe;
• a digital beam former for controlling the sensitivity of the antenna elements;
• and
• a time multiplexed switch matrix for receiving the received signals from the overlapped subarray feed network, and for timing the transmission of the received signals to the receiver a Doppler function comprising a Doppler frequency filter followed by a Doppler compensation function, wherein the Doppler function is performed on the recieved signal prior to the digital beamforming function, the Doppler frequency filter differentiates between a multiple number of the received signals, and the Doppler compensation function compensates for the target motion induced phase shift for a center frequency of a particular Doppler frequency filter, wherein the Doppler compensation function and the digital beamforming function are performed separately on each frequency of the recieved signals from the Doppler frequency filter.