中文摘要：

首先从理论和实测数据模拟两方面分析了SA取消后各类误差源对GPS测速的影响,推导并计算了GPS单点测速可能达到的精度水平。然后用静态数据模拟动态测速试验和实测动态数据测速与同步高精度惯导测速的动态试验进行验证。结果表明,采用载波相位导出的多普勒观测值使用静态数据模拟动态测速,其精度可以达到mm/s级;用接收机输出的多普勒观测值进行测速时,其精度为cm/s级。在动态测速试验中,GPS单点测速方法（即多普勒观测值测速与导出多普勒观测值测速）间的符合精度达到cm/s级,与高精度的惯导测速结果的符合精度为dm/s级,而且和运动载体的动态条件（如加速度和加速度变化率的大小）具有很强的相关性。

英文摘要：

Error sources of velocity estimate have been changed since SA was off. Firstly in- fluence quantities of all kinds of error sources of velocity determination were analyzed, the potential accuracy of GPS absolute velocity estimate was derived from both theory and field GPS data simulation. After that, two tests were carried on to evaluate the performance of GPS absolute velocity determination in the case of a static and an airborne GPS receiver and INS （inertial navigation system） device kinematic case. In static mode, the user velocity has been estimated to several mm/s with the carrier-phase derived doppler measurements, and several cm/s with the receiver generated doppler measurements. In kinematic mode, GPS absolute velocity estimates were compared with the synchronized measurements from the high accuracy INS. The root mean square statistics of the velocity discrepancies between GPS and INS comes up to dm/s, moreover it has a strong correlation with the acceleration or jerk of the aircraft movement.