Data processing system for a phased array antenna

• US 4,872,016 A
• Filed: 09/06/1988
• Issued: 10/03/1989
• Est. Priority Date: 09/06/1988
• Status: Expired due to Fees

• Current Assignee: Grumman Aerospace Corporation Bethpage NY 11714
• Original Assignee: Grumman Aerospace Corporation (Northrop Grumman Corporation)
• Inventors: Kress, Robert W.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US07/240,960
• Time in Patent Office: 392 Days
• Field of Search: 342/380, 342/383, 342/372
• US Class Current: 342/380
• CPC Class Codes: G01S 7/2813 Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays specially adapted to secondary radar systems G01S13/762; aerials or aerials systems H01Q21/29, H01Q25/00
• CPC Class Codes: H01Q 3/2617 Array of identical elements

Abstract

A data processing system for a phased array antenna consisting of an array of transmit/receive elements which result in a significant reduction in the data processing requirements for the received signals. In operation, the RF transmitted and received beams are formed and steered in a conventional manner with a phase shifter and amplitude weighting for each element. However, a simplifying approximation is made in the signal processing of the received signals for interference suppression, which results in minimal degradation of the system performance. In such a system, interference suppression is obtained by generating nulls in the receive antenna pattern in the direction of the interference. The nulls are produced by adjusting the phase and amplitude (weight) of the received signal from each array element just enough to null the interference with minimal impact on the rest of the antenna pattern. Pursuant to the present invention, the signal processing requirements are significantly reduced by summing the outputs of adjacent array elements to produce a lesser number of summed signals, less than the number of elements in the array. Each summed signal is then directed to a weighted amplifier controlled to weigh the contribution of the particular summed signal to a composite output signal formed by a composite summing circuit, which sums the weighted output signals of all of the weighted amplifiers.

Claims

1. A data processing system for an electronically scanned, phased array antenna radar system, comprising;

a. an electronically scanned, phased array antenna comprising an array of n radiating and receiving elements, and a phase control circuit for each element, wherein the phase front of the antenna beam is controlled to steer the antenna beam by individually controlling the gain and phase excitation of each radiating element;

b. a signal receiver, including an interference suppressor processor, for processing signals received by said phased array antenna, wherein the receiver controls the gain and phase shift of the signals received by the elements to match the transmitted beam pattern, and wherein interference suppression is achieved by generating nulls in the received antenna pattern in the direction in which the interference is to be suppressed by adjusting the elements, and wherein the signal processing requirements are reduced by, means for summing the outputs of the phase control circuits for adjacent array elements to produce a number of summed signals less than the number of elements in the array, and each summed signal being directed to a weighted amplifier controlled by said interference suppressor processor to weight the contribution of that particular summed signal to a composite output signal formed by a composite summing means for summing the weighted output signals of the weighted amplifiers.

2. A data processing system for an electronically scanned, phased array antenna radar system, as claimed in claim 1, each radiating and receiving element comprising an endfire element having a maximum gain along the longitudinal axis of that element.

3. A data processing system for an electronically scanned, phased array antenna radar system, as claimed in claim 1, comprising n/2 summing means for said n elements, and wherein signals from two adjacent elements are summed by each summing means.

4. A data processing system for an electronically scanned, phased array antenna radar system, as claimed in claim 1, comprising n/3 summing means for said n elements, and wherein signals from three adjacent elements are summed by each summing means.

5. A data processing system for an electronically scanned, phased array antenna radar system, as claimed in claim 1, comprising a phase adjusting circuit, coupled between each element and the summing means for that element, for controlling the phase of the signal from that element to the summing means for that element.

6. A data processing system for an electronically scanned, phased array antenna radar system, as claimed in claim 1, comprising an interference suppressor processor, having an input from each summing means and an input from said composite summing means, for processing the input signals and for supplying an output control signal to each weighted amplifier.