A null despreader for interference suppression in GPS

作者：Hwang Suk seung; Shynk John J^*

来源：International Journal of Satellite Communications and Networking, 2011, 29(4): 315-332.

DOI：10.1002/sat.976

• global positioning system
• interference suppression
• beamforming
• null despreader

The Global Positioning System (GPS) utilizes low-power spread-spectrum signals and thus is vulnerable to various types of high-power interference sources. It requires at least four satellites for estimating three-dimensional user positions and the receiver clock bias. In this paper, we propose a blind adaptive GPS receiver that is based on a new despreader and the one-stage constant modulus (CM) array. The despreader consists of a conventional GPS despreader and a so-called null despreader, which together modify the received signal so that the CM array can extract the GPS signal of interest. The beamformer not only rejects jammers and extracts the GPS signal of interest without explicit direction-of-arrival (DOA) information of any of the signals but also it has a low computational complexity compared with conventional techniques, such as minimum-variance distortionless-response (MVDR) beamforming. As a conventional despreader can recover only one GPS signal, multiple despreaders are usually required for separating multiple GPS signals. We also explore an extension of the proposed null despreader to detect multiple GPS signals. Computer simulation examples are presented to illustrate the performance of the receiver for different types of jammer signals.

• 出版日期2011-8