Adaptive electronically steerable phased array

• US 4,189,733 A
• Filed: 12/08/1978
• Issued: 02/19/1980
• Est. Priority Date: 12/08/1978
• Status: Expired due to Term

• Current Assignee: Northrop Corporation
• Original Assignee: Northrop Corporation
• Inventors: Malm, Robert
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US05/967,572
• Time in Patent Office: 438 Days
• Field of Search: 343/100 LE, 343/100 CL, 343/100 SA, 343/854
• US Class Current: 342/368
• CPC Class Codes: H01Q 3/2617 Array of identical elements
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854

Abstract

An adaptive antenna system which enhances the desired signal in the output of the system while reducing the interference from signals arriving from directions other than that of the desired signal. The antenna system operates in conjunction with a modulation/demodulation system for spreading and despreading the spectrum of the desired signal. By a series of deterministic perturbations of phase shifters or other signal varying devices attached to the antenna elements, the system measures the effects of these perturbations: (1) on the wide-band energy in the output of the antenna, prior to spectrum despreading, and (2) on the narrow-band energy following despreading, and then adjusts the phase shifters or other signal varying devices so as to enhance the desired signal while reducing the interfering signals.

Claims

1. An adaptive receiving antenna system comprising:

a. a plurality of antenna elements for receiving electromagnetic signals,

b. a plurality of signal varying means connected to the outputs of predetermined ones of the antenna elements for varying each of the outputs of said predetermined antenna elements,

c. output combining means connected to the outputs of the signal varying means, and to the antenna elements to which no signal varying means are connected, for receiving and combining the outputs of the predetermined ones of the signal varying means and the outputs of the antenna elements to which no signal varying means are connected,

d. wide-band energy measurement means, connected to the output of the output combining means, for measuring the wide-band energy therein,

e. despreader means, connected to the output of the output combining means, for receiving and despreading the spectrum of the desired signal and for reducing the band-width of the signals emerging from the despreading means,

f. narrow-band energy measurement means, connected to the output of the despreader means, for measuring the narrow-band energy therein, and

g. controller and correlator means connected to the output of the wide-band energy measurement means and to the output of the narrow-band energy measurement means, which correlator and controller means controls each of the signal varying means to introduce variations into the outputs from the signal varying means so as to decrease the output from the wide-band energy measurement means and increase the output from the narrow-band energy measurement means.

2. The system as described in claim 1 wherein the signal varying means comprise phase shifting means for varying the phase of the output of the signal varying means.

3. The system as described in claim 1 wherein the signal varying means comprise magnitude varying means for varying the magnitudes of the outputs from the signal varying means.

4. The system as described in claim 1 wherein the signal varying means comprise phase and magnitude shifting means for varying the phases and magnitudes of the outputs from the signal varying means.

5. The system of claim 1 or 2 or 3 or 4 wherein the controller and correlator means in addition comprises random bit means for generating and inserting pseudo-random changes in the variations introduced into the signal varying means by the controller and correlator means.