Phased array multiple area nulling antenna architecture

• US 5,579,016 A
• Filed: 09/20/1995
• Issued: 11/26/1996
• Est. Priority Date: 09/20/1995
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: TRW Inc. (Northrop Grumman Corporation)
• Inventors: Wong, William C., Westall, Kenneth E., Wolcott, James L.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US08/531,262
• Time in Patent Office: 433 Days
• Field of Search: 342/378, 342/383, 342/384
• US Class Current: 342/378
• CPC Class Codes: H01Q 3/22 varying the orientation in accordance with variation of frequency of radiated wave
• CPC Class Codes: H01Q 3/2605 Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays

Abstract

An adaptive nulling communication system for nulling undesired signals from communication signals in multiple separate and distinct coverage areas is disclosed. The adaptive nulling communication system includes a phased array antenna having multiple receiving elements to form a single aperture for receiving multiple signals. A first set of beam forming networks coupled to the phased array antenna forms the multiple separate and distinct coverage areas. A distribution network coupled to the first set of beam forming networks distributes the signals received from these coverage areas. A nulling processor having a second beam forming network coupled to the distribution network weights and adjusts the second beam forming network in response to the undesired signals to null these undesired signals from the communication signals.

Claims

1. An adaptive nulling communication system for nulling undesired signals from communication signals in multiple separate and distinct coverage areas having at least two separate and distinct primary coverage areas, said system comprising:

phased array antenna means for receiving a plurality of signals, said phased array antenna means including a plurality of receiving elements for receiving said plurality of signals, each of said signals having a signal characteristic;

a plurality of first beam forming networks coupled to said phased array antenna means for providing signal coverage to said multiple separate and distinct coverage areas, each of said first beam forming networks coupled to each of said receiving elements;

distribution means for distributing a plurality of signals received from said multiple separate and distinct coverage areas;

a plurality of second beam forming networks coupled to said distribution means for nulling said undesired signals; and

a plurality of processors corresponding to at least the number of separate and distinct primary coverage areas for weighting and adjusting said plurality of second beam forming networks in response to said undesired signals, wherein said plurality of second beam forming networks nulls said undesired signals from said communication signals, each of said processors assigned to a separate and distinct coverage area of interest and each of said processors including characterizing means for identifying communication signals from an assigned coverage area of interest and for suppressing communication signals outside said assigned coverage area of interest based on said signal characteristics of said plurality of signals.

2. The adaptive nulling communication system as defined in claim 1 wherein said phased array antenna means includes a phased array antenna, said phased array antenna includes said plurality of receiving elements forming a single aperture.

3. The adaptive nulling communication system as defined in claim 1 wherein each of said first beam forming networks forms multiple separate and distinct coverage areas.

4. The adaptive nulling communication system as defined in claim 3 further comprising a controller for weighting and adjusting each of said first beam forming networks to form said multiple separate and distinct coverage areas.

5. The adaptive nulling communication system as defined in claim 4 wherein said controller weights and adjusts each of said first beam forming networks over time to cover different sets of multiple separate and distinct coverage areas for specific time frames to provide agile beam coverage.

6. The adaptive nulling communication system as defined in claim 1 wherein each of said characterizing means includes filtering means for filtering said communication signals from said assigned coverage area and for rejecting said communication signals from outside said assigned coverage area.

7. The adaptive nulling communication system as defined in claim 1 wherein each of said characterizing means includes variable oscillator means for tracking said communication signals from said assigned coverage area and for rejecting said communication signals from outside said assigned coverage area.

8. An adaptive nulling communication system for nulling undesired signals from communication signals in multiple separate and distinct coverage areas having at least two separate and distinct primary coverage areas, said system comprising:

phased array antenna having a plurality of receiving elements forming a single aperture for receiving a plurality of signals, each of said signals having a signal characteristic;

a plurality of first beam forming networks coupled to said phased array antenna, each of said first beam forming networks coupled to each of said receiving elements wherein each of said first beam forming networks forms multiple separate and distinct coverage areas;

distribution network coupled to said plurality of first beam forming networks to distribute a plurality of signals received from said multiple separate and distinct coverage areas; and

a plurality of nulling processors corresponding to at least the number of separate and distinct primary coverage areas, each of said nulling processors having a second beam forming network coupled to said distribution network, each of said nulling processors weights and adjusts a second beam forming network in response to said undesired signals to null said undesired signals from said communication signals, wherein each of said nulling processors includes characterizing means for suppressing users outside a coverage area of interest based on said signal characteristics of said plurality of signals.

9. The adaptive nulling communication system as defined in claim 8 wherein said receiving elements are selected from a group consisting of dipoles, crossed dipoles, helices, patches and horns.

10. The adaptive nulling communication system as defined in claim 8 wherein each of said first beaming forming networks simultaneously receives said plurality of signals from said receiving elements.

11. The adaptive nulling communication system as defined in claim 10 wherein each of said first beam forming networks includes a plurality of first variable amplitude and phase elements corresponding to the number of receiving elements and a first summer, wherein each of said first variable amplitude and phase elements weights and adjusts the amplitude and phase of signals received by each receiving element to generate resultant signals and said first summer sums said resultant signals in said first summer to generate said signals received from said multiple separate and distinct coverage areas.

12. The adaptive nulling communication system as defined in claim 8 further comprising a controller for weighting and adjusting each of said first beam forming networks to form said multiple separate and distinct coverage areas.

13. The adaptive nulling communication system as defined in claim 12 wherein said controller weights and adjusts each of said first beam forming networks over time to cover different sets of multiple separate and distinct coverage areas for specific time frames to provide agile beam coverage.

14. The adaptive nulling communication system as defined in claim 8 wherein each of said receiving elements is coupled to each of said first beam forming networks and each of said first beam forming networks is coupled to each of said second beam forming networks.

15. The adaptive nulling communication system as defined in claim 8 wherein each of said second beam forming networks includes a plurality of second variable amplitude and phase elements corresponding to the number of first beam forming networks and a second summer, wherein each of said second variable amplitude and phase elements weights and adjusts the amplitude and phase of said signals received from said multiple separate and distinct coverage areas to generate resultant signals and said second summer sums the resultant signals to generate a summed signal.

16. The adaptive nulling communication system as defined in claim 8 wherein each of said nulling processors includes a correlator for comparing a summed signal from a second beam forming network to each signal from each first beam forming network to determine which multiple separate and distinct coverage areas said undesired signals are transmitting from.

17. The adaptive nulling communication system as defined in claim 16 wherein each of said nulling processors further includes a high speed beam select switch for sampling each of said signals from each of said first beam forming networks.

18. The adaptive nulling communication system as defined in claim 16 wherein each of said correlators simultaneously compares a summed signal from a second beam forming network with each of said signals from each of said first beam forming networks.

19. A method for adaptively nulling undesired signals from communication signals in multiple separate and distinct coverage areas having at least two separate and distinct primary coverage areas, said method comprising the steps of:

receiving a plurality of signals from a phased array antenna having a plurality of receiving elements forming a single aperture;

coupling each of said receiving elements to each of a plurality of first beam forming networks;

forming multiple separate and distinct primary coverage areas and offset coverage areas from said plurality of first beam forming networks;

distributing a plurality of signals received in said primary coverage areas and said offset coverage areas to a plurality of second beam forming networks;

weighting and adjusting said plurality of second beam forming networks in response to said undesired signals with a plurality of nulling processors corresponding to the number of separate and distinct primary coverage areas to null said undesired signals from said communication signals;

assigning a separate and distinct primary coverage area of interest to each of said nulling processors; and

characterizing said communication signals in each of said nulling processors based on signal characteristics to suppress communication signals outside said assigned coverage area of interest of each of said nulling processors.

20. The method as defined in claim 19 wherein the step of forming multiple separate and distinct primary coverage areas and offset coverage areas from said plurality of first beam forming networks further includes the step of weighting and adjusting a plurality of variable amplitude and phase elements in each of said first beam forming networks.

21. The method as defined in claim 19 wherein the step of weighting and adjusting said plurality of second beam forming networks further includes the step of weighting and adjusting a plurality of second variable amplitude and phase elements in each second beam forming network.