Adaptive spherical array with non-uniformly spaced taps for GPS signal processing

The Global Positioning System (GPS) is widely used for many applications but its performance can be impacted significantly by the environment. This can be overcome to a large extend by processing the signal in space and time. The space processing is achieved with a seven element planar array followed by an algorithm to calculate the antenna weights in such a way that the interferences can be nulled. The time processing is implemented with uniformly-spaced tap delays. This paper reports some alternatives to improve the performance of the system. First, a spherical array replaces the present planar array to increase the line-of-sight (LOS) at low elevation angles. Then, the tap delay spacing is incorporated. Results show an improvement in the bit-error-rate (BER) performance when non-uniformly spaced taps are used.