Adaptive nulling methods for GPS reception in multiple-interference environments
First Claim
1. A method of reducing the contribution of at least one interference signal to a composite signal that includes said interference signal and at least one global positioning system (GPS) signal wherein each interference signal propagates along an associated signal path, the method comprising the steps of:
- receiving said composite signal with an array of antenna elements to form a plurality of respective received signals wherein said antenna elements are positioned in a spatial arrangement;
combining said received signals to form a combined signal;
expressing a weight vector that comprises the phases of a plurality of said received signals as a combination of a set of orthonormal basis vectors that are multiplied by a corresponding set of initial coefficients wherein said orthonormal basis vectors have a mathematical interrelationship with said spatial arrangement;
for a first one of said orthonormal basis vectors, adjusting said phases via said interrelationship to obtain a respective coefficient that corresponds with a reduction of said combined signal; and
repeating said adjusting step for the remainder of said orthonormal basis vectors;
said contribution reduced by the reduction of said combined signal via a spatial relationship between said signal path and said spatial arrangement; and
the reduction of said combined signal hastened by the uncoupled nature of said orthonormal basis vectors.
1 Assignment
0 Petitions
Accused Products
Abstract
Methods are disclosed for receiving GPS signals in the presence of multiple interference signals. The methods feature the orthogonal projection of sub-optimal weight vectors onto sets of orthonormal basis vectors. They facilitate the use of single-port reception techniques in which power is monitored only at a single GPS array output port regardless of the number of array elements. The methods do not require prior knowledge of interference signal structure and their use of uncoupled orthonormal basis vectors facilitates the simultaneous adjustment of array weights and rapid convergence to an optimal set of weights.
-
Citations
28 Claims
-
1. A method of reducing the contribution of at least one interference signal to a composite signal that includes said interference signal and at least one global positioning system (GPS) signal wherein each interference signal propagates along an associated signal path, the method comprising the steps of:
-
receiving said composite signal with an array of antenna elements to form a plurality of respective received signals wherein said antenna elements are positioned in a spatial arrangement; combining said received signals to form a combined signal; expressing a weight vector that comprises the phases of a plurality of said received signals as a combination of a set of orthonormal basis vectors that are multiplied by a corresponding set of initial coefficients wherein said orthonormal basis vectors have a mathematical interrelationship with said spatial arrangement; for a first one of said orthonormal basis vectors, adjusting said phases via said interrelationship to obtain a respective coefficient that corresponds with a reduction of said combined signal; and repeating said adjusting step for the remainder of said orthonormal basis vectors; said contribution reduced by the reduction of said combined signal via a spatial relationship between said signal path and said spatial arrangement; and the reduction of said combined signal hastened by the uncoupled nature of said orthonormal basis vectors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A method of reducing the contribution of at least one interference signal to a composite signal that includes said interference signal and at least one global positioning system (GPS) signal wherein each interference signal propagates along an associated signal path, the method comprising the steps of:
-
receiving said composite signal with an array of antenna elements to form a plurality of respective received signals wherein said antenna elements are positioned in a spatial arrangement; combining said received signals to form a combined signal; expressing a weight vector that comprises the phases of all but a reference one of said received signals as a combination of a set of orthonormal basis vectors that are multiplied by a corresponding set of initial coefficients wherein said orthonormal basis vectors have a mathematical interrelationship with said spatial arrangement; for a first one of said orthonormal basis vectors, adjusting said phases via said interrelationship to obtain a respective coefficient that corresponds with a reduction of said combined signal; and repeating said adjusting step for the remainder of said orthonormal basis vectors; said contribution reduced by the reduction of said combined signal via a spatial relationship between said signal path and said spatial arrangement; and the reduction of said combined signal hastened by the uncoupled nature of said orthonormal basis vectors. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
-
Specification