摘要
为了测试卫星定位系统接收机的性能,须用信号模拟器来模拟各种条件下真实的卫星发射信号。卫星信号模拟器由软件、硬件和上位机三部分组成。系统主要包含目标运动轨迹计算、误差计算、导航电文生成及信号调制发射等功能模块。中频信号处理中的多普勒频移模拟是高动态卫星信号模拟器要解决的一项关键技术。为此,提出了一种全相参的多普勒模拟算法,基于真实的高动态运动模型解算出伪码和载波的频率字,在现场可编程门阵列(FPGA)中通过数控振荡器(NCO)设计产生真实的动态卫星信号。通过实际测试并与理论数据进行了比对验证,模拟出的动态特性与真实卫星信号的多普勒特性一致。
For the purpose of testing the performances of satellite positioning system receivers, a signal simulator is needed that can emulate the real satellite signals under all kinds of conditions. The high dynamic satellite signal simulator device consists of hardware, software and position machine. The system comprises the target trajectory calculation module, the error calculation module, the satellite navigation parameters generation module, and the signal modulation module, etc. Doppler frequency shift simulation in the error calculation module is a key technique that must be solved for the high dynamic satellite signal simulator. A physical meaning of the Doppler simulation in a satellite channel is given. According to the frequency parameters of code and carrier calculated from a high dynamic model, the satellite transmitting signal could be produced by the numerical controlle oscillater（NCO） design based on field programmable gate array（FPGA）. By the real hardware testing and validating it with the theoretic data, the results show that high dynamic simulation corresponds to the rules of the real satellite signal＇s Doppler characteristics.
出处
《航空学报》
EI
CAS
CSCD
北大核心
2008年第5期1252-1257,共6页
Acta Aeronautica et Astronautica Sinica
基金
国家自然科学基金(60027001)
航空基金(2006ZC51032)
关键词
卫星定位系统
信号模拟器
多普勒频移模拟
高动态
全相参
satellite positioning system
signal simulator
Doppler frequency shift simulation
high dynamic
phase-coherent
