“北斗二代”B1I信号捕获技术研究与实现

发布时间：2018-08-01 12:52

【摘要】：随着我国自主研制的“北斗二代”卫星导航系统成功投入运营,用户设备部分即北斗卫星导航接收机的研制也蓬勃发展,其中信号捕获是接收机研制过程中至关重要的第一步。目前信号捕获技术的研究主要集中于提高对GPS卫星信号捕获的精度和灵敏度等性能,然而“北斗二代”B1I信号比特极性翻转频繁的特性,导致针对GPS卫星信号的捕获算法无法直接应用于北斗导航接收机中,因此研究适用于“北斗二代”B1I信号的捕获技术对于北斗导航接收机的发展具有重要意义。论文首先对“北斗二代”卫星信号的结构和传统捕获算法进行了分析和研究,针对“北斗二代”B1I信号比特极性翻转频繁的问题,设计了时域并行的粗捕获算法,并对该算法进行了性能分析和实验验证。针对粗捕获得到的载波多普勒频移精度较低的问题,论文设计了利用切比雪夫线性最小二乘曲线拟合法改进数值逼近算法的载波频率精细捕获算法,并对该算法进行性能分析和实验验证,实验结果显示该算法对载波频率的估计精度达到20Hz,有效地提高了载波频率的估计精度。针对城市、室内等弱信号环境下的信号捕获,论文为GEO卫星和IGSO/MEO卫星分别设计了差分非相干积分算法和本地调制NH码的相干积分算法,通过弱信号实验测试,验证了算法可以提高7dB的弱信号捕获能力。最后论文将粗捕获算法、精捕获算法和弱信号捕获算法组成信号捕获系统,在FPGA+DSP的导航接收机开发平台上进行实现,并使用北斗二代卫星信号模拟器产生的信号对捕获系统进行性能测试,验证了硬件实现的正确性,实现对“北斗二代”B1I信号高精度和较高灵敏度的捕获。
[Abstract]:With the successful operation of the "Beidou second generation" satellite navigation system developed by our country, the development of the part of user equipment, Beidou satellite navigation receiver, is booming, in which signal acquisition is the first important step in the development of the receiver. At present, the research of signal capture mainly focuses on improving the accuracy and sensitivity of GPS satellite signal acquisition. However, the "Beidou second generation" B1I signal has the characteristics of frequent bit polarity reversal. Because the acquisition algorithm for GPS satellite signal can not be directly applied to Beidou navigation receiver, it is of great significance to study the acquisition technology of Beidou second generation B1I signal for the development of Beidou navigation receiver. Firstly, the structure of Beidou second generation satellite signal and the traditional acquisition algorithm are analyzed and studied. Aiming at the problem that the bit polarity flips frequently in Beidou second generation B1I signal, a parallel coarse acquisition algorithm in time domain is designed. The performance of the algorithm is analyzed and verified by experiments. Aiming at the low accuracy of carrier Doppler frequency shift obtained from coarse acquisition, a carrier frequency fine acquisition algorithm using Chebyshev linear least square curve fitting method is designed. The performance of the algorithm is analyzed and the experimental results show that the accuracy of carrier frequency estimation is up to 20 Hz, which can effectively improve the accuracy of carrier frequency estimation. For the signal capture in the weak signal environment such as city and indoor, the differential incoherent integral algorithm and the coherent integral algorithm of local modulated NH code are designed for GEO satellite and IGSO/MEO satellite respectively. It is verified that the algorithm can improve the weak signal acquisition ability of 7dB. Finally, the rough acquisition algorithm, fine acquisition algorithm and weak signal acquisition algorithm are composed of the signal acquisition system, which is implemented on the FPGA DSP navigation receiver development platform. The performance of the acquisition system is tested by using the signal generated by the Beidou second generation satellite signal simulator, which verifies the correctness of the hardware implementation and realizes the acquisition of the "Beidou second generation" B1I signal with high accuracy and high sensitivity.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN967.1

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