The GPS vector tracking loop based on the iterated unscented unscented Kalman filter under the large initial error

Recently, several researchers have studied the vector tracking loop to obtain an improved signal tracking performance in GPS receiver. The advantage of the vector tracking loop is that noise is reduced in all of the tracking channels. Also this can operate successfully when the conventional tracking loop approach fails. However the vector tracking loop provides a degraded performance when the navigation filter has the large initial error because this loop controls the digital controlled oscillator of each channel by using the navigation filter. To solve this problem, this paper proposes the vector tracking loop based on the iterated unscented Kalman filter (IUKF). The simulation results show that the vector tracking loop based on the IUKF is better than that based on the EKF under the large initial error.