GPS AOA estimation based on a modified despreader

The Global Positioning System (GPS) is designed to estimate the locations of users or objects, and has a variety of civilian and military applications. Although angles-of-arrival (AOAs) may be required to enhance the desired GPS signals, it is difficult to estimate explicit AOA information because a GPS signal has a low power relative to the noise level. In this paper, we propose a GPS AOA estimation method based on a modified despreader and the constant modulus (CM) array cost function. This technique has a low computational complexity compared with other AOA estimation methods, such as the Multiple Signal Classification (MUSIC) algorithm, because it does not require a singular value decomposition (SVD). It also has good estimation performance in low signal-to-noise ratio (SNR) environments.