中文摘要：

结合同相-正交环跟踪算法对数据调制的不敏感性以及全数字载波跟踪环设计灵活的特点,提出一种基于同相-正交环跟踪算法的全数字GPS载波跟踪方案。重点对其关键模块在FPGA平台上的设计与实现方法进行了研究。经过仿真验证,该设计方案在-30dB信噪比环境下能够准确地解调导航电文并实现对多普勒频移的精确跟踪,有效地改善了GPS载波跟踪环在低信噪比环境下的同步时间与跟踪精度。

英文摘要：

A design and implementation scheme of all digital carrier tracking loop is presented.Based on Costas loop tracking algorithm,the scheme utilizes the insensitiveness of Costas loop to data modulation and flexibility of all digital carrier tracking loop.The key modules′ design of the carrier tracking loop on FPGA development platform is researched emphatically.Simulation results demonstrate that the designed Costas loop can extract the navigation data bits from the original GPS signals and track Doppler frequency shift precisely with the signal noise ratio（SNR）of-30dB.It can effectively improve the tracking performance in synchronous time and tracking precision in the SNR environment of-30dB.