GNSS接收机中采样率对时间鉴别力的影响  

Influence of Sampling Rate on Time Discrimination in GNSS Receiver

作　　者：柯颋[1] 胡修林[1] 刘禹圻[1] 冉一航[1] 

机构地区：[1]华中科技大学电子与信息工程系,武汉430074

出　　处：《宇航学报》2010年第12期2722-2729,共8页Journal of Astronautics

摘　　要：探讨了GNSS系统中,伪码跟踪环的时间鉴别力与采样率之间的定量关系,提出了时间鉴别力的性能评估准则及其计算方法。然后以GPSL5信号为例,重点考察多普勒效应对采样系统时间鉴别力的影响。实验表明,一般来说,随着采样率的增加,采样系统的时间鉴别力也会随之提高。但是当采样率接近或者恰好等于码片速率的整数倍时,采样系统的时间鉴别力会陡然下降。虽然多普勒效应能够显著改善等量采样系统的时间鉴别力,但是与设计良好的非等量采样率相比,其改善程度十分有限。本文提出的算法可以应用于GNSS数字接收机设计工作,以选择"较优"的采样率,即以较低的硬件成本实现较高的时间鉴别力。The quantitative relationship between time discrimination of DLL and sampling rate in GNSS（Global Navigation Satellite System）receiver is investigated.A calculable performance evaluation criterion is proposed.And then using the GPS L5 code as an example,the influence of sampling rate on time discrimination is analyzed with the emphasis on Doppler effect.The results show that in general,with the increase of sampling rate,the time discrimination gets better,except for the special case of commensurable sampling,i.e.,as the sampling rate is close to an integer multiple of chip rate,the time discrimination would degrade dramatically.Although in the special case,time discrimination can be significantly improved by using Doppler effect,it is still very poor compared with other well designed noncommensurable sampling rates.Therefore,the proposed method can be applied for GNSS receiver design to choose a better sampling rate,and can achieve better time discrimination performance with lower implementation cost.

关 键 词：GNSS 接收机 采样率 时间鉴别力 性能评估准则 

分 类 号：TN967.1[电子电信—信号与信息处理]