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专著名称:
China Satellite Navigation Conference (CSNC) 2012 Proceedings
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主编单位: China Satellite Navigation Conference (CSNC) 2012 Proceedings
出版时间: 2012-05-16
出版社: Springer-Verlag Berlin Heidelberg
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编写人员: 巴晓辉
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著作性质: 电子、通信与自动控制技术
编辑出版单位: China Satellite Navigation Conference (CSNC) 2012 Proceedings
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参编内容: 应用于弱GNSS信号的牵引和跟踪方法
著作简介: Usually, a GPS receiver uses the digital phase-locked loop (DPLL) or digital frequency-locked loop (DFLL) as the carrier tracking loop. The success rate of pull-in process may be low under the condition of very low signal-to-noise rate (SNR), which will affect the time to first fix (TTFF) even if the receiver can successfully acquire the weak signal. An effective algorithm based on FFT for pull-in and tracking processing of weak GNSS signal is presented, which overcomes the influence of the navigation bit transition. The algorithm realizes a lot non-coherent integration through FFT processing and every input point of FFT is the accumulation of coherent integration of 20 ms. The outputs of FFT show the frequency offset, according to which the local carrier frequency is adjusted. The experimental results show that this method can effectively improve the success rate of the pull-in process and reduce the time-consuming of the pull-in process when the GPS signal power level is as low as -155 dBm. After pull-in process, the method also can keep steady tracking under the same condition.
其它备注: 国外出版-外文