Apparatus, methods and computer program for evaluating multiple null forming antenna processors and jammers

• US 5,940,033 A
• Filed: 01/20/1998
• Issued: 08/17/1999
• Est. Priority Date: 01/20/1998
• Status: Expired due to Term

• Current Assignee: The United States Government As Represented By The Secretary Of The Army
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Rodman, Edward F., Locher, Robert J., Burtis, Cynthia E., McAvoy, David P.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/009,512
• Time in Patent Office: 574 Days
• Field of Search: 342/417, 342/378, 342/379, 342/16, 342/19
• US Class Current: 342/378
• CPC Class Codes: G01S 7/36 Means for anti-jamming , e.g. ECCM, i.e. electronic counter-counter measures
• CPC Class Codes: H01Q 3/2611 Means for null steering; Adaptive interference nulling

Abstract

An automated interactive antenna patterning apparatus depicts adaptive array antenna patterns and selects adaptive antenna array characteristics. The apparatus comprises an antenna modeling means building an adaptive antenna description, representing a number of antenna elements, means for determining angle-of-arrival, means for rank-ordering, means for sorting, means for antenna patterning and data output means providing composite antenna patterns for each array receiver. The adaptive antenna patterning apparatus better determines adaptive null steering antenna patterns produced in the presence of numerous interference sources. Also, automated interactive antenna patterning methods provide for depicting adaptive array antenna patterns and selecting adaptive antenna array characteristics, comprising the steps of forming an adaptive antenna description, determining angle-of-arrival, rank-ordering interference peaks, building a nulling table in a sorting means, calculating a total interference signal level and a signal to noise ratio plus interference ratio for each array receivers, forming an antenna pattern at the receivers, applying each pattern to determine nulled interference signal-to-noise level at each receiver and providing a data output means with the composite antenna pattern for each receiver. A computer-readable medium whose contents cause a computer system to depict adaptive antenna array characteristics as an article of manufacture is also provided.

Claims

1. An automated interactive antenna patterning apparatus for depicting adaptive array antenna patterns and selecting adaptive antenna array characteristics, comprising:

a means for antenna modeling, having a data loading means and a loop back inquiry means, receives a plurality of input data files and a plurality of operator parameter selections;

said plurality of input data files including a plurality of antenna files and an antenna gain table;

said plurality of operator parameter selections including a number of antenna elements, antenna element spacing, maximum null depth, type of antenna, type of element, selected signal and a maximum null depth;

said modeling means constructs an adaptive antenna description, said antenna description representing a plurality of elements;

a means for link operating permits the operator to input said plurality of antenna configuration files and select an antenna gain table for each of said plurality of elements of the antenna description;

said modeling means simulates a plurality of interference signals, a nonadaptive reference element, a plurality of incoming signal inputs and a plurality of total noise inputs in the presence of said antenna description;

said modeling means resolves said plurality of interference signals as seen by said antenna description;

a node counter is initialized and checked;

said link selection means permits the operator to select a single link operating mode or multiple link operating mode for said antenna description;

when said single link operating mode is selected, said antenna description is transmitted to a means for determining angle-of-arrival;

said angle-of-arrival determination means, having a plurality of angle-of-arrival algorithms, calculates a plurality of angles of arrival of said plurality of interference signals for each receiving antenna of the antenna description at said node counter;

a jammer signal initial noise level means and a jammer signal variables means utilizing said plurality of angles of arrival and a background noise input cooperate with said angle-of-arrival determination means to calculate an initial noise level for a selected antenna of said antenna description;

said initial noise level is provided to a said jammer signal initial noise level means, said jammer signal initial noise level means and said jammer signals variable means provide a prenulled Signal-to-Noise ratio to a means for rank-ordering;

said rank-ordering means, having a plurality of ordering algorithms, calculates a plurality of interference signal peaks of said antenna description and rank orders said plurality of interference signal peaks by order of signal strength in a nulling table input provided to a means for sorting;

said sorting means constructs a nulling table;

said nulling table indicating where to place a null in antenna patterns providing a composite antenna pattern with the highest achievable Signal-to-Noise plus Interference ratio, S/(N+I);

said sorting means directs nulls at said plurality of interfering signals while simultaneously directing a peak at a desired signal;

said sorting means applies nulls to the incoming signals representing signal gain and delay factors and sorts a plurality of simulated jammer signals;

said nulling table, adjusting a plurality of gain factors and a plurality of delay factors, and in cooperation with a nulling table application means provides a sorted output to said nulling table application means;

said nulling table application means, having a plurality of nulling algorithms, utilizes said nulling table and said sorted output to calculate a Signal-to-Noise Plus Interference ratio of said array and applies a nulling table output to a plurality of incoming signal inputs and a plurality of total noise inputs to reduce said plurality of incoming signals between said plurality of total noise inputs and said maximum null depth, said nulling table application means provides said nulling table output to a nulled interference means;

said nulled interference means and a desired signal means of said nulling table application means calculates a nulled Signal-to-Noise Plus Interference output to produce a series of nulls, said nulled interference means providing said nulled Signal-to-Noise Plus Interference output to a link selection means;

said link selection means compares said nulled Signal-to-Noise Plus Interference output with an array threshold value from said initial link status output;

when the operator has selected a single link, said link selection means increments a node once; and

an antenna patterning means constructs an adaptive antenna pattern output provided to a data output means depicting a single antenna array pattern.

2. The automated interactive antenna patterning apparatus, as recited in claim 1, further comprising:

said rank-ordering means orders said plurality of interference signal peaks of said antenna description and rank orders said plurality of interference signal peaks by order of signal strength in said nulling table input according to strongest and weakest signal levels;

said plurality of operator parameter selections including a number of antenna elements, antenna element spacing, maximum null depth, type of antenna, type of element, selected signal, a maximum null depth;

said plurality of input data files including a link data file, a jammer file, an antenna file and a gain table allowing the operator to input a plurality of friendly and threat equipment laydowns, a plurality of desired and threat signal levels for each of said plurality of receiver antennas;

said link data file containing information about the relevant communications links of a given network; and

said jammer file having location, signal power and frequency data for each of a plurality of jammers of interest.

3. The automated interactive antenna patterning apparatus, as recited in claim 2, wherein:

the number of said plurality of nulls which can be applied to incoming signals is one less than the total number of antennas provided in said antenna description;

said plurality of nulls not being negated by previous nulls;

said plurality of nulls not being degraded by previous nulls; and

the formation of said plurality of nulls being based on the setting of the phase shifts and gains.

4. The automated interactive antenna patterning apparatus, as recited in claim 3, further comprising:

the operator selecting a virtual width beam;

said rank-ordering means detects said plurality of inflection points when a rising signal strength changes to a falling signal strength by swinging said virtual width beam through said array in one degree increments on a 360°

scale; and

said interference signal peaks being points of maximum signal strength corresponding to a plurality of strong jammers.

5. The automated interactive antenna patterning apparatus, as recited in claim 4, further comprising:

said plurality of operator parameter selections permit placing a second null on each of said peaks, beginning with the strongest peak; and

said plurality of operator parameter selections permit optimizing said desired signal with a plurality of spare tracking loops.

6. The automated interactive antenna patterning apparatus, as recited in claim 5, further comprising said nulling table, having a listing of nulls and optimizations compiled by said sorting means, represents signal gain and delay factors.

7. The automated interactive antenna patterning apparatus, as recited in claim 6, further comprising:

said nulled interference means calculates a signal level and an interferer level reduced below a total noise level;

said nulled interference means having power set to said total noise level because signals cannot be reduced below the noise floor; and

said signal level and said interferer levels cannot be reduced by more than said maximum null depth.

8. The automated interactive antenna patterning apparatus, as recited in claim 7, further comprising:

said rank-ordering means disregarding a plurality of peaks which fall within boresight; and

said rank ordering means, in constructing said nulling table, provides said sorted output in order of signal strength.

9. The automated interactive antenna patterning apparatus, as recited in claim 8, further comprising said antenna pattern output is provided for each of said receivers in a communications scenario.

10. The automated interactive antenna patterning apparatus, as recited in claim 8, further comprising:

said data output means is a printing means when the operator has selected said single antenna output pattern;

said printing means provides a printed report of a plurality of communications link status characteristics; and

said data output means displays said adaptive antenna pattern output and said plurality of communications link status characteristics.

11. The automated interactive antenna patterning apparatus, as recited in claim 8, further comprising:

said link selection means permits the operator to select said single link mode of operation; and

said link selection means permits the operator to select a multiple network link mode of operation.

12. The automated interactive antenna patterning apparatus, as recited in claim 1, further comprising a computer system having a plurality of software programs.

13. An automated interactive antenna patterning method for depicting adaptive array antenna patterns and selecting adaptive antenna array characteristics, comprising the steps of:

loading a plurality of input data files and a plurality of operator parameter selections onto a means for antenna modeling;

said antenna modeling means having a data loading means and a loop back inquiry means, said plurality of input data files including a plurality of antenna files and an antenna gain table, said plurality of operator parameter selections including a number of antenna elements, antenna element spacing, maximum null depth, type of antenna, type of element, selected signal and a maximum null depth;

constructing an adaptive antenna description in said antenna modeling means, said antenna description representing a plurality of elements;

inputting said plurality of antenna configuration files with a means for link operating;

selecting an antenna gain table for each of said plurality of elements of the antenna description;

said modeling means simulating a plurality of interference signals, a nonadaptive reference element, a plurality of incoming signal inputs and a plurality of total noise inputs in the presence of said antenna description;

said modeling means resolving said plurality of interference signals as seen by said antenna description;

initializing a node counter;

checking said node counter;

selecting a single link operating mode or multiple link operating mode for said array with said link selection means;

transmitting said antenna description to a means for determining angle-of-arrival when said single link operating mode is selected;

calculating a plurality of angles of arrival of said plurality of interference signals for each receiving antenna of the antenna description at said node counter, by said angle-of-arrival determination means, said angle-of-arrival determination means having a plurality of angle-of-arrival algorithms;

calculating an initial noise level for a selected antenna of said antenna description by said angle-of-arrival determination means, said angle-of-arrival determination means cooperating with a jammer signal initial noise level means and a jammer signal variables means, utilizing said plurality of angles of arrival and a background noise input;

providing said initial noise level to said jammer signal initial noise level means, said jammer signal initial noise level means and said jammer signals variable means providing a prenulled Signal-to-Noise ratio to a means for rank-ordering;

calculating a plurality of interference signal peaks of said antenna description, said rank ordering means, having a plurality of ordering algorithms, rank orders said plurality of interference signal peaks by order of signal strength in a nulling table input provided to a means for sorting;

constructing a nulling table in said sorting means;

placing a null in an antenna pattern, said nulling table provides a composite antenna pattern with the highest achievable Signal-to-Noise plus Interference ratio, S/(N+I);

directing nulls at said plurality of interfering signals, said sorting means simultaneously directing a peak at a desired signal;

applying the nulls to the incoming signals representing signal gain and delay factors, said sorting means, having constructed said nulling table, sorts a plurality of simulated jammer signals;

adjusting a plurality of gain factors and a plurality of delay factors, said nulling table in cooperation with a means for nulling application provides a sorted output to said nulling table application means;

calculating a Signal-to-Noise Plus Interference ratio of said array, said nulling table application means, having a plurality of nulling algorithms, using said nulling table and said sorted output, applies a nulling table output to a plurality of incoming signal inputs and a plurality of total noise inputs to reduce said plurality of incoming signals between said plurality of total noise inputs and said maximum null depth said nulling table application means provides said nulling table output to a means for nulled interference;

calculating a nulled Signal-to-Noise Plus Interference output, said nulled interference means and a desired signal means of said nulling table application means, producing a series of nulls, said nulled interference means provides said nulled Signal-to-Noise Plus Interference output to a link selection means;

comparing said nulled Signal-to-Noise Plus Interference output with an array threshold value from said initial link status output, in said link selection means;

incrementing a node once by said link selection means when the operator has selected a single link; and

constructing an adaptive antenna pattern output in said patterning means, said antenna patterning means providing said adaptive antenna pattern output to a data output means depicting a single antenna array pattern.

14. The automated interactive antenna patterning method, as recited in claim 13, wherein:

said rank-ordering means orders said plurality of interference signal peaks of said antenna description and rank orders said plurality of interference signal peaks by order of signal strength in said nulling table input according to strongest and weakest signal levels;

said plurality of operator parameter selections including a number of antenna elements, antenna element spacing, maximum null depth, type of antenna, type of element, selected signal, a maximum null depth;

said plurality of input data files including a link data file, a jammer file, an antenna file and a gain table allowing the operator to input a plurality of friendly and threat equipment laydowns, a plurality of desired and threat signal levels for each of said plurality of receiver antennas;

said link data file containing information about the relevant communications links of a given network; and

said jammer file having location, signal power and frequency data for each of a plurality of jammers of interest.

15. The automated interactive antenna patterning method, as recited in claim 14, wherein:

the number of said plurality of nulls which can be applied to incoming signals is one less than the total number of antennas provided in said antenna description;

said plurality of nulls not being negated by previous nulls;

said plurality of nulls not being degraded by previous nulls; and

the formation of said plurality of nulls being based on the setting of the phase shifts and gains.

16. The automated interactive antenna patterning method, as recited in claim 15, further comprising the steps of:

selecting a virtual width beam;

detecting said plurality of inflection points by said rank-ordering means when a rising signal strength changes to a falling signal strength by swinging said virtual width beam through said array in one degree increments on a 360°

scale; and

said interference signal peaks being points of maximum signal strength corresponding to a plurality of strong jammers.

17. The automated interactive antenna patterning method, as recited in claim 16, wherein:

said plurality of operator parameter selections permit placing a second null on each of said peaks, beginning with the strongest peak; and

said plurality of operator parameter selections permit optimizing said desired signal with a plurality of spare tracking loops.

18. The automated interactive antenna patterning method, as recited in claim 17, further comprising said nulling table, having a listing of nulls and optimizations compiled by said sorting means, represents signal gain and delay factors.

19. The automated interactive antenna patterning method, as recited in claim 18, further comprising the steps of:

calculating a signal level and an interferer level by said nulled interference means reduced below a total noise level;

said nulled interference means having power set to said total noise level because signals cannot be reduced below the noise floor; and

reducing said signal level and said interferer levels by no more than said maximum null depth.

20. The automated interactive antenna patterning method, as recited in claim 19, further comprising the steps of:

said rank-ordering means disregarding a plurality of peaks falling within boresight; and

said rank ordering means, in constructing said nulling table, provides said sorted output in order of signal strength.

21. The automated interactive antenna patterning method, as recited in claim 20, further comprising providing said antenna pattern output for each of said receivers in a communications scenario.

22. The automated interactive antenna patterning method, as recited in claim 20, further comprising the steps of:

said data output means being a printing means when the operator has selected said single antenna output pattern;

providing a printed report of a plurality of communications link status characteristics from said printing means; and

displaying said adaptive antenna pattern output and said plurality of communications link status characteristics by said data output means.

23. The automated interactive antenna patterning method, as recited in claim 20, wherein:

said link selection means permits the operator to select said single link mode of operation; and

said link selection means permits the operator to select a multiple network link mode of operation.

24. The automated interactive antenna patterning method, as recited in claim 13, further comprising the step of employing a computer system having a plurality of software programs.

25. A computer-readable medium whose contents cause a computer system to depict adaptive array antenna patterns and select adaptive antenna array characteristics, said computer system having an antenna modeling means, a means for determining angle-of-arrival, a means for rank-ordering, a means for sorting and a means for antenna patterning, comprising:

said antenna modeling means, having a data loading means and a loop back inquiry means, receives a plurality of input data files and a plurality of operator parameter selections;

said plurality of input data files including a plurality of antenna files and an antenna gain table;

said plurality of operator parameter selections including a number of antenna elements, antenna element spacing, maximum null depth, type of antenna, type of element, selected signal and a maximum null depth;

said modeling means constructs an adaptive antenna description, said antenna description representing a plurality of elements;

a means for link operating permits the operator to input said plurality of antenna configuration files and select an antenna gain table for each of said plurality of elements of the antenna description;

said modeling means simulates a plurality of interference signals, a nonadaptive reference element, a plurality of incoming signal inputs and a plurality of total noise inputs in the presence of said antenna description;

said modeling means resolves said plurality of interference signals as seen by said antenna description;

a node counter is initialized and checked;

said link selection means permits the operator to select a single link operating mode or multiple link operating mode for said array;

when said single link operating mode is selected, said array is transmitted to said angle-of-arrival determination means;

said angle-of-arrival determination means, having a plurality of angle-of-arrival algorithms, calculates a plurality of angles of arrival of said plurality of interference signals for each receiving antenna of the antenna description at said node counter;

a jammer signal initial noise level means and a jammer signal variables means utilizing said plurality of angles of arrival and a background noise input cooperate with said angle-of-arrival determination means to calculate an initial noise level for a selected antenna of said antenna description;

said initial noise level is provided to jammer signal initial noise level means, jammer signal initial noise level means and said jammer signals variable means provide a prenulled Signal-to-Noise ratio to said rank-ordering means;

said rank-ordering means, having a plurality of ordering algorithms, calculates a plurality of interference signal peaks of said antenna description and rank orders said plurality of interference signal peaks by order of signal strength in a nulling table input provided to said sorting means;

said sorting means constructs a nulling table;

said nulling table indicating where to place a null in antenna patterns provides a composite antenna pattern with the highest achievable Signal-to-Noise plus Interference ratio, S/(N+I);

said sorting means directs nulls at said plurality of interfering signals while simultaneously directing a peak at a desired signal;

said sorting means applies nulls to the incoming signals representing signal gain and delay factors and sorts a plurality of simulated jammer signals;

said nulling table, adjusting a plurality of gain factors and a plurality of delay factors, and in cooperation with a nulling table application means provides a sorted output to said nulling table application means;

said nulling table application means, having a plurality of nulling algorithms, utilizes said nulling table and said sorted output to calculate a Signal-to-Noise Plus Interference ratio of said array and applies a nulling table output to a plurality of incoming signal inputs and a plurality of total noise inputs to reduce said plurality of incoming signals between said plurality of total noise inputs and said maximum null depth, said nulling table application means provides said nulling table output to a nulled interference means;

said nulled interference means and a desired signal means of said nulling table application means calculates a nulled Signal-to-Noise Plus Interference output to produce a series of nulls, said nulled interference means providing said nulled Signal-to-Noise Plus Interference output to a link selection means;

said link selection means compares said nulled Signal-to-Noise Plus Interference output with an array threshold value from said initial link status output;

when the operator has selected a single link, said link selection means increments a node once; and

said antenna patterning means constructs an adaptive antenna pattern output provided to a data output means depicting a single antenna array pattern.

26. The computer-readable medium, as recited in claim 25, wherein:

said rank-ordering means orders said plurality of interference signal peaks of said antenna description and rank orders said plurality of interference signal peaks by order of signal strength in said nulling table input according to strongest and weakest signal levels;

said plurality of operator parameter selections including a number of antenna elements, antenna element spacing, maximum null depth, type of antenna, type of element, selected signal, a maximum null depth;

said plurality of input data files including a link data file, a jammer file, an antenna file and a gain table allowing the operator to input a plurality of friendly and threat equipment laydowns, a plurality of desired and threat signal levels for each of said plurality of receiver antennas;

said link data file containing information about the relevant communications links of a given network; and

said jammer file having location, signal power and frequency data for each of a plurality of jammers of interest.

27. The computer-readable medium, as recited in claim 26, wherein:

the number of said plurality of nulls which can be applied to incoming signals is one less than the total number of elements provided in said antenna description;

said plurality of nulls not being negated by previous nulls;

said plurality of nulls not being degraded by previous nulls; and

the formation of said plurality of nulls being based on the setting of the phase shifts and gains.

28. The computer-readable medium, as recited in claim 27, further comprising:

the operator selecting a virtual width beam;

said rank-ordering means detects said plurality of inflection points when a rising signal strength changes to a falling signal strength by swinging said virtual width beam through said antenna description in one degree increments on a 360°

scale; and

said interference signal peaks being points of maximum signal strength corresponding to a plurality of strong jammers.

29. The computer-readable medium, as recited in claim 28, further comprising:

said plurality of operator parameter selections permit placing a second null on each of said peaks, beginning with the strongest peak; and

said plurality of operator parameter selections permit optimizing said desired signal with a plurality of spare tracking loops.

30. The computer-readable medium, as recited in claim 29, further comprising said nulling table, having a listing of nulls and optimizations compiled by said sorting means, represents signal gain and delay factors.

31. The computer-readable medium, as recited in claim 30, further comprising:

said nulled interference means calculates a signal level and an interferer level reduced below a total noise level;

said nulled interference means having power set to said total noise level because signals cannot be reduced below the noise floor; and

said signal level and said interferer levels cannot be reduced by more than said maximum null depth.

32. The computer-readable medium, as recited in claim 31, further comprising:

said rank-ordering means disregarding a plurality of peaks which fall within boresight; and

said rank ordering means, in constructing said nulling table, provides said sorted output in order of signal strength.

33. The computer-readable medium, as recited in claim 32, further comprising said adaptive antenna pattern output is provided for each of said receivers in a communications scenario.

34. The computer-readable medium, as recited in claim 32, further comprising:

said data output means is a printing means when the operator has selected said single antenna output pattern;

said printing means provides a printed report of a plurality of communications link status characteristics; and

said data output means displays said adaptive antenna pattern output and said plurality of communications link status characteristics.

35. The computer-readable medium, as recited in claim 32, further comprising:

said link selection means permits the operator to select said single link mode of operation; and

said link selection means permits the operator to select a multiple network link mode of operation.