GPS微弱信号捕获跟踪算法

上官伟; 王晶晶; 蔡伯根; 王剑; 梁前浩

doi:10.19818/j.cnki.1671-1637.2010.05.019

GPS微弱信号捕获跟踪算法

doi: 10.19818/j.cnki.1671-1637.2010.05.019

上官伟^{1, 2,},
王晶晶¹,
蔡伯根¹,
王剑^{1, 2},
梁前浩¹

1.
北京交通大学电子信息工程学院, 北京 100044
2.
北京交通大学轨道交通控制与安全国家重点实验室, 北京 100044

基金项目:

国家自然科学基金项目 60736047

国家863计划项目 2009AA11Z221

轨道交通控制与安全国家重点实验室自主研究课题 RCS2009ZT013

中央高校基本科研业务费专项资金项目 2009JBM005

铁道部科技研究开发计划项目 Z2009-059

详细信息

作者简介:
上官伟（1979-）, 男, 陕西乾县人, 北京交通大学讲师, 工学博士, 从事交通信息工程及控制研究

中图分类号: U491.51
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出版历程
- 收稿日期: 2010-06-24
- 刊出日期: 2010-10-25

Acquisition and track algorithm of GPS weak signal

1.
School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China
2.
State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, Beijing 100044, China

More Information

Author Bio:
SHANGGUAN Wei(1979-), male, lecturer, PhD, +86-10-51687111, wshg@bjtu.edu.cn

摘要

摘要: 在GPS微弱信号捕获算法设计中, 为提高捕获灵敏度, 采用相干积分与非相干积分结合的方式消除数据码长度对相干积分增益的影响, 采用差分相干积分减小非相干积分中的平方衰耗。为了提高信号捕获速度和精度, 利用FFT工具进行伪码与载波频率捕获, 采用延迟锁定环(DLL) 与锁相环(PLL) 实现GPS微弱信号的跟踪。最后对GPS微弱信号的捕获跟踪算法进行仿真实现。应用结果表明: 通过仿真技术能有效地复现出捕获和跟踪载噪比为25dB.Hz^-1的GPS微弱信号, 差分相干积分捕获灵敏度比相干-非相干积分高0.8dB, 频率捕获误差小于1.25Hz, 码捕获误差小于0.1码元。
- 信息工程 /
- GPS微弱信号 /
- 相干积分与非相干积分 /
- FFT快速伪码捕获 /
- 载波跟踪
Abstract: During the design process of acquisition algorithm for GPS weak signal, in order to increase acquisition sensitivity, a method that combined coherent integration with noncoherent integration was adopted to eliminate the influence of data code length on coherent integration gain, and a differential coherent integration was proposed to reduce the square tenuation in noncoherent integration. Instead of traditional methods, FFT-based code and carrier acquisition algorithm was implemented to improve acquisition speed and accuracy. DLL and PLL were used in GPS weak signal track. Finally, the acquisition and track of GPS weak signal were realized by simulation. The result indicates that it is a good approach to track and capture GPS weak signal with the CNR of 25 dB·Hz^-1 by simulation technology. The sensitivity of differential coherent acquisition is 0.8 dB larger than the sersitivity of coherent-noncoherent integration, frequency acquisition error is less than 1.25 Hz, and code acquisition error is less than 0.1 code.
- information engineering /
- GPS weak signal /
- coherent-noncoherent integration /
- FFT code acquisition /
- carrier tracking

HTML全文

图 1 相干-非相干积分原理

Figure 1. Principle of coherent-noncoherent integration

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图 2 差分相干积分原理

Figure 2. Principle of differential coherent integration

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图 3 FFT码捕获原理

Figure 3. Principle of FFT code acquisition

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图 4 GPS信号跟踪环原理

Figure 4. Tracking loop principle of GPS signal

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图 5 码跟踪环原理

Figure 5. Tracking loop principle of code

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图 6 载波相位跟踪环原理

Figure 6. Tracking loop principle of carrier phase

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图 7 GPS微弱信号捕获结果比较

Figure 7. Comparison of acquisition results for GPS weak signal

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图 8 GPS微弱信号跟踪情况

Figure 8. Tracking condition of GPS weak signal

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图 9 高灵敏度GPS软件接收机在微弱信号环境中的应用

Figure 9. Application of high-sensitive GPS software receiver in weak signal environments

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表 1 测量数据与跟踪数据比较

Table 1. Comparison between measurement data and tracking data

参数	NovAtel接收机	软件接收机	误差
T₀/s	201 600	201 600	0.000 000 000 0
M₀/rad	-0.538 531 468 980	-0.279 852 300 000	0.258 679 169 0
C′_uc/rad	0.000 006 046 146 154	0.000 006 046 146 154	0.000 000 000 0
C′_us/rad	0.000 004 302 710 295	0.000 004 302 710 295	0.000 000 000 0
C′_rc/rad	288.437 5	288.437 5	0.000 000 000 0
C′_rs/rad	117.093 75	117.093 75	0.000 000 000 0
C′_hc/rad	0.000 000 104 308 128 400	0.000 000 104 308 128 400	0.000 000 000 0
C′_hs/rad	0.000 000 158 324 837 700	0.000 000 158 324 837 700	0.000 000 000 0
i₀/rad	0.942 885 294 250	0.942 886 600 000	0.000 001 305 8
i′/ (rad·s^-1)	-0.000 000 000 028 215 461	-0.000 000 000 104 647 200	0.000 000 000 1

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