Small Polarimetric Adaptive Array for Airborne GPS Jammer Suppression
Abstract
MIT Lincoln Laboratory has designed, built, tested, and analyzed a small polarimetric adaptive array for airborne GPS jammer suppression. The array has 7 channels and is configured as a square array. The array consists of a right-hand circularly polarized (RHCP) reference element and 3 dual-linearly polarized elements. The rationale for the design was to create a 7-channel array with 1 RHCP reference element that had acceptable levels of mutual coupling and fit within a 7 inch by 7 inch footprint. The approach taken was to convert 3 of the 4 elements of a 4-element RHCP array to 3 dual-linearly polarized elements. This modification actually simplifies the construction of the array by eliminating 3 hybrid couplers. This modification results in up to 6 degrees of freedom for the polarimetric array. The concept of using dual-polarized elements in an adaptive array was considered by R.T. Compton, Jr. and presented in his text, Adaptive Antennas. He showed that using dual-polarized elements allows a polarization null to be directed towards an interfering source while receiving a desired signal that is co-linear with the interferer and the receiver, provided the desired signal and the interfering signal have somewhat different polarizations. He also showed that using an array with different element patterns can have better performance than an array of isotropic elements under certain conditions. This paper will concentrate on the measured performance of the small polarimetric adaptive array. The complex element patterns of the array were measured on a small ground plane in an MIT Lincoln Laboratory indoor chamber, and a few azimuthal patterns were measured with the array on a Falcon 20 aircraft in the Patuxent River Chamber.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2004
- Accession Number
- ADA432593
Entities
People
- Dennis Blejer
- Eugene C. Ngai
- Tri T. Phuong
Organizations
- Massachusetts Institute of Technology