To solve the inter carrier interference （ICI） elimination problem of an M-band wavelet multi-carrier modulation system, this paper analyzes the principle of the ICI caused by the Doppler frequency shift and its math...To solve the inter carrier interference （ICI） elimination problem of an M-band wavelet multi-carrier modulation system, this paper analyzes the principle of the ICI caused by the Doppler frequency shift and its mathematical expression based on the M-band wavelet multi-carrier modulation system model. Through the analysis of the mathematical expression and combining with the perfect reconstruction conditions of the filter banks, we propose the design conditions of an M-band filter to reduce and eliminate the ICI. The impulse response model of the filter design conditions and an iterative algorithm is also established. The simulation results show that the proposed ICI reduction and elimination methods can effectively improve the system performance.展开更多
In deep space exploration,many engineering and scientific requirements require the accuracy of the measured Doppler frequency to be as high as possible.In our paper,we analyze the possible frequency measurement points...In deep space exploration,many engineering and scientific requirements require the accuracy of the measured Doppler frequency to be as high as possible.In our paper,we analyze the possible frequency measurement points of the third-order phase-locked loop(PLL)and find a new Doppler measurement strategy.Based on this finding,a Doppler frequency measurement algorithm with significantly higher measurement accuracy is obtained.In the actual data processing,compared with the existing engineering software,the accuracy of frequency of 1 second integration is about 5.5 times higher when using the new algorithm.The improved algorithm is simple and easy to implement.This improvement can be easily combined with other improvement methods of PLL,so that the performance of PLL can be further improved.展开更多
针对位置欺骗如何影响接收机的问题,使用TEXBAT(Texas Spoofing Test Battery)提供的2组无欺骗干扰场景数据集和2组不同场景的GPS位置欺骗数据集,建立了GPS位置欺骗模型,分析了欺骗场景下两种相位对齐模式对欺骗攻击的影响;利用GNSS-SD...针对位置欺骗如何影响接收机的问题,使用TEXBAT(Texas Spoofing Test Battery)提供的2组无欺骗干扰场景数据集和2组不同场景的GPS位置欺骗数据集,建立了GPS位置欺骗模型,分析了欺骗场景下两种相位对齐模式对欺骗攻击的影响;利用GNSS-SDR软件接收机对TEXBAT的原始高保真数字采样数据进行数据处理,分别得到软件接收机受欺骗与未受欺骗时的接收机载噪比、载波多普勒、码速率等随时间的变化情况;分析了两个位置欺骗场景对软件接收机跟踪阶段输出值的影响。实验结果表明,载噪比有大于3(dB·Hz)的波动,码速率方差会发生阶段性的增加和减少;多普勒频率的变化取决于欺骗场景的选取,不同场景的位置欺骗从不同角度有效影响了接收机定位结果。展开更多
正交时频空(orthogonal time frequency space,OTFS)技术是近年来出现的一种新型多载波调制技术。在OTFS技术中,数据信号在时延—多普勒域产生,经过逆偶有限傅里叶变换实现信号的时频二维扩展,以解决正交频分复用(orthogonal frequency ...正交时频空(orthogonal time frequency space,OTFS)技术是近年来出现的一种新型多载波调制技术。在OTFS技术中,数据信号在时延—多普勒域产生,经过逆偶有限傅里叶变换实现信号的时频二维扩展,以解决正交频分复用(orthogonal frequency division multiplexing,OFDM)技术在时频双选信道下干扰严重的问题。介绍了OTFS技术的基本原理,通过仿真验证其相比于OFDM技术的优势。对其研究现状进行分析总结,指出OTFS技术中的多址接入、信道估计和线性接收机等研究方向目前有待解决的问题。对OTFS技术在雷达—通信一体化系统中的应用前景进行分析和展望。展开更多
基金supported by the National Natural Science Foundation of China (Grant No.60872114)
文摘To solve the inter carrier interference （ICI） elimination problem of an M-band wavelet multi-carrier modulation system, this paper analyzes the principle of the ICI caused by the Doppler frequency shift and its mathematical expression based on the M-band wavelet multi-carrier modulation system model. Through the analysis of the mathematical expression and combining with the perfect reconstruction conditions of the filter banks, we propose the design conditions of an M-band filter to reduce and eliminate the ICI. The impulse response model of the filter design conditions and an iterative algorithm is also established. The simulation results show that the proposed ICI reduction and elimination methods can effectively improve the system performance.
基金supported by the National Natural Science Foundation of China(Grant Nos.11773060,11973074,U1831137 and 11703070)National Key Basic Research and Development Program(2018YFA0404702)+1 种基金Shanghai Key Laboratory of Space Navigation and Positioning(3912DZ227330001)the Key Laboratory for Radio Astronomy of CAS。
文摘In deep space exploration,many engineering and scientific requirements require the accuracy of the measured Doppler frequency to be as high as possible.In our paper,we analyze the possible frequency measurement points of the third-order phase-locked loop(PLL)and find a new Doppler measurement strategy.Based on this finding,a Doppler frequency measurement algorithm with significantly higher measurement accuracy is obtained.In the actual data processing,compared with the existing engineering software,the accuracy of frequency of 1 second integration is about 5.5 times higher when using the new algorithm.The improved algorithm is simple and easy to implement.This improvement can be easily combined with other improvement methods of PLL,so that the performance of PLL can be further improved.
文摘针对位置欺骗如何影响接收机的问题,使用TEXBAT(Texas Spoofing Test Battery)提供的2组无欺骗干扰场景数据集和2组不同场景的GPS位置欺骗数据集,建立了GPS位置欺骗模型,分析了欺骗场景下两种相位对齐模式对欺骗攻击的影响;利用GNSS-SDR软件接收机对TEXBAT的原始高保真数字采样数据进行数据处理,分别得到软件接收机受欺骗与未受欺骗时的接收机载噪比、载波多普勒、码速率等随时间的变化情况;分析了两个位置欺骗场景对软件接收机跟踪阶段输出值的影响。实验结果表明,载噪比有大于3(dB·Hz)的波动,码速率方差会发生阶段性的增加和减少;多普勒频率的变化取决于欺骗场景的选取,不同场景的位置欺骗从不同角度有效影响了接收机定位结果。
文摘正交时频空(orthogonal time frequency space,OTFS)技术是近年来出现的一种新型多载波调制技术。在OTFS技术中,数据信号在时延—多普勒域产生,经过逆偶有限傅里叶变换实现信号的时频二维扩展,以解决正交频分复用(orthogonal frequency division multiplexing,OFDM)技术在时频双选信道下干扰严重的问题。介绍了OTFS技术的基本原理,通过仿真验证其相比于OFDM技术的优势。对其研究现状进行分析总结,指出OTFS技术中的多址接入、信道估计和线性接收机等研究方向目前有待解决的问题。对OTFS技术在雷达—通信一体化系统中的应用前景进行分析和展望。
