提高GPS卫星数字中频信号捕获性能的方法

GPS卫星发射的信号处于以加性高斯白噪声AWGN为干扰的背景下,若载噪比CNR较差,可能会使接收机一直都处于失捕状态,满足不了某些实时性定位应用的要求。为此,对现有的一种捕获方法———FFT相关法进行数值改进,以减小错捕、漏捕概率,并在若干个捕获周期都失捕的情况下,提出了应对的捕获措施,增大重新捕获的概率,以提高系统的可靠性。

If the ratio of carrier and noise is not high enough when the signals from the GPS satellites are under the disturbance of white Gaussian noise, the receiver may be always in the state of no acquisition and could not satisfy the demand of real-time location. Therefore, we improved an acquisition method, which made improvement on the calculation of FFT correlation to reduce the probability of acquisition by mistake or no acquisition. And as for the case of no acquisition in several periods, we put forward a measure to increase the probability of re-acquisition to enhance the reliability of the system.