摘要
地球表面接收到的卫星导航信号强度通常远低于环境热噪声,并且其所处电磁环境越来越复杂,人们越来越关心在干扰环境下导航接收机的工作性能。模数转换器(ADC)作为数字式导航接收机中射频通道与基带处理的中间环节,其量化造成的有用信号损耗直接影响着接收机的整体性能。对于连续波干扰(CWI)与热噪声环境下ADC量化对卫星导航信号的影响,现有文献大多是基于数值模拟实验寻找答案,缺少理论推导。通过概率统计理论深入研究了在CWI干扰环境下任意位数(bits)ADC均匀量化对接收机相关信干噪比的影响,得出了明确的量化后信干噪比表达式,并给出近似最优的ADC量化门限选取法则。通过数学推导和仿真分析得出结论,在没有辅助抗干扰手段和采用均匀量化的情况下,2 bit的ADC量化即可达到最大的输出信干噪比。
The power of the satellite navigation signals received at the earth surface is typically much lower than the ambient thermal noise, and increasingly complex electromagnetic environment needs to be dealt with. The per- formance of navigation receivers in interference scenarios has got more and more attention. As the bridge between rac[io frequency channel and baseband processor, Analog to Digital Converter （ADC） directly impacts the overall performance of GNSS receivers through its quantization loss on useful signal. The ADC quantization loss on the post-correlation signal-to-noise ratio has been researched mostly based on simulation or experiment, without theoret- ical formula derivation. The expression of uniform quantization loss with arbitrary bits ADC is theoretically derived based on the probability and statistics theory, when the input interference is a continuous wave （CWI）. A near-op- timal quantization interval criterion is given with analyzing the minimize quantization loss. It is concluded that 2 bits ADC quantization can achieve the maximum post-correlation signal to Noise plus interference ratio （SINR） in the uniform quantization case, when there is no other anti-jamming means.
出处
《科学技术与工程》
北大核心
2013年第7期1847-1851,共5页
Science Technology and Engineering
