Adaptive antenna array and method of operating same

Claim 3

A method according to claim 1 and further including the steps of: changing the phase of each of said R K signals by 90° to obtain respective signals R KC ; demodulating said R K and R KC signals; bandpass filtering said demodulated R K and R KC signals to obtain signals S K and S KC respectively of said second bandwidth and which are representative of the individually demodulated S KA signals; bandreject filtering said demodulated R K and R KC signals to obtain signals I K +N K and I KC +N KC respectively lying outside said second bandwidth and which are representative of said individual interference signals I KA and said noise N KA ; performing time average correlations on signals S S and S K ; S S and S KC ; I S +N S and I N +N K ; I S +N S and I KC +N KC ; and using said time average correlations to modify said complex weights u k +jv k .

Claim 4

A method according to claim 2 wherein said complex weights are modified according to the expressions ##EQU1## where the overbar indicates time average correlation of the signals below, and where C and C 2 are predetermined loop gains.

Claim 5

A method according to claim 2 wherein said complex weights are modified according to the expressions ##EQU2## where the overbar indicates time average correlation of the signals below, and where C 1 and C 2 are predetermined loop gains.

Claim 6

A method according to claim 2 wherein said steps for forming terms R K , R KC , S K , S KC , I K +N K , and I KC +N KC are performed sequentially for various values of K, 1≦K≦N.

Claim 7

A method according to claim 2 wherein said steps of forming terms R K , R KC , S K , I K +N K , and I KC +N KC are performed in parallel where 1≦K≦N.

Claim 8

A method according to claim 4 wherein said predetermined loop gains are constant.

Claim 9

A method according to claim 4 wherein said predetermined loop gains are time variable.

Claim 10

An adaptive antenna array for maximizing the ratio of information signal power to interference plus noise power comprised of: a plurality of N antenna elements for generating composite electrical signals R K =S KA +I KA +N KA where 1≦K≦N, S KA is a modulated information signal in a first frequency band, I KA is at least one interference signal in said first frequency band, and N KA is noise produced in said antenna elements; multiplication means for multiplying each of said signals R K by respective complex weights u k +jv k to form product terms; adder means for summing all of said product terms to thereby form a signal R S ; demodulation means for demodulating said R S signal; bandpass filter means for filtering said demodulated R S signal to obtain a signal S S of a second bandwidth that is substantially less than said first bandwidth and which is representative of the sum of the demodulated S KA signals; bandreject filter means for filtering said demodulated R S signal to obtain a signal I S +N S lying outside of said second bandwidth which is representative of the sum of said interference signal I KA and said noise N KA ; means for generating signals P se and P I which respectively indicate the power in said signals S S and I S +N S and; means for modifying said complex weights u k +jv k such that the time rate of change u k is proportional to the rate of change of T e with respect to u k , and such that the time rate of change of v k is proportional to the rate of change T e with respect to v k , where T e is representative of the ratio of P se to P I .

Claim 11

An adaptive antenna array for maximizing the ratio of information signal power to interference plus noise power comprised of: a plurality of N antenna elements for generating composite electrical signals R K =S KA +I KA +N KA where 1≦K≦N, S KA is a modulated information signal in a first frequency band, I KA is at least one interference signal in said first frequency band, and N KA is noise produced in said antenna elements; multiplication means for multiplying each of said signals R K by respective complex weights u k +jv k to form product terms; adder means for summing all of said product terms to thereby form a signal R S ; demodulation means for demodulating said R S signal; bandpass filter means for filtering said demodulated R S signal to obtain a signal S S of a second bandwidth that is substantially less than said first bandwidth and which is representative of the sum of the demodulated S KA signals; bandreject filter means for filtering said demodulated R S signal to obtain a signal I S +N S lying outside of said second bandwidth which is representative of the sum of said interference signal I KA and said noise N KA ; means for generating signals P se and P I which respectively indicate the power in said signals S S and I S +N S and; means for modifying said complex weights u k +jv k such that the time rate of change u k is proportional to the rate of change of T e with respect to u k , and such that the time rate of change of v k is proportional to the rate of change T e with respect to v k , where T e is representative of the ratio of P se to P I .

Claim 12

An adaptive antenna array according to claim 9 and further including, means for changing the phase of each of said R K signals by 90° to obtain respective R KC signals; means for demodulating said R K and R KC signals; means for bandpass filtering said demodulated R K and R KC signals to obtain signals S K and S KC respectively of said second bandwidth and which are representative of the individually demodulated S KA signals; means for bandreject filtering said demodulated R K and R KC signals to obtain signals I K +N K and I KC +N KC respectively lying outside said second bandwidth and which are representative of said individual interference signals I KA and said noise N KA ; means for performing time average correlations on signals S S and S K ; S S and S KC ; I S +N S and I N +N K ; I S +N S and I KC +N KC ; and means for combining said time average correlations to modify said complex weights u k +jv k .

Claim 13

An adaptive antenna array according to claim 10 wherein said means for combining including means for modifying said complex weights according to the expressions ##EQU3## where the overbar indicates time average correlation of the signals below, and where C, and C 2 are loop gains.

Claim 14

An adaptive antenna array according to claim 10 wherein said means for combining includes means for modifying said complex weights according to the expressions ##EQU4## where the overbar indicates time average correlation of the signals below, and where C 1 and C 2 are loop gains.

Claim 15

An adaptive antenna array according to claim 10 and further including switching means between said antenna elements and a single set of said means for demodulating means for bandpass filtering means for bandreject filtering, and means for time average correlating to enable terms R K , R KC , S K , S KC , I K +N K and I KC +N KC to be sequentially formed for various values of K, 1≦K≦N.