小波滤波在时间同步系统中应用研究
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摘要
利用全球导航卫星系统(GNSS)接收机输出的秒脉冲(1PPS)信号作为标准信号,对本地振荡器输出的1PPS信号实施同步,实现了时间同步系统。针对GNSS接收机输出的1PPS信号抖动噪声对时间同步系统同步性能的影响,研究了一种抑制抖动影响的滤波器。滤波器采用小波滤波器结合滑动平均滤波器的方式,其中小波滤波采用自定义的阈值及阈值函数。对所实现的滤波器开展了滤波处理实验,实验结果表明,该滤波方案对GNSS接收机输出的1PPS信号的噪声抑制效果优于常用的卡尔曼滤波器,所实现的时间同步系统输出的1PPS信号精度达到1.17 ns,相比于GNSS接收机输出的1PPS信号精度提高一个数量级。
We have realized a time synchronization system using the one pulse per second(1 PPS) signal provided by the global navigation satellite system(GNSS) receiver as reference signal to synchronize the 1 PPS signal output of the local oscillator. Aiming at the influence of the jitter noise of GNSS receiver 1 PPS signal on synchronization performance of the time synchronization system, we designed a filter that can suppress the jitter effect. The filter adopted the manner of wavelet filter combining with moving average filter, in which the wavelet filter used custom-defined threshold and threshold functions. Filtering processing experiment was conducted using the designed filter, the experiment results reveal that the jitter noise suppression effect for the 1 PPS signal of the GNSS receiver using the proposed filtering scheme is better than that using commonly used Kalman filter. The 1 PPS output signal accuracy of the proposed time synchronous system reaches 1.17 ns, which is one order superior to the 1 PPS signal accuracy of GNSS receiver.
We have realized a time synchronization system using the one pulse per second(1 PPS) signal provided by the global navigation satellite system(GNSS) receiver as reference signal to synchronize the 1 PPS signal output of the local oscillator. Aiming at the influence of the jitter noise of GNSS receiver 1 PPS signal on synchronization performance of the time synchronization system, we designed a filter that can suppress the jitter effect. The filter adopted the manner of wavelet filter combining with moving average filter, in which the wavelet filter used custom-defined threshold and threshold functions. Filtering processing experiment was conducted using the designed filter, the experiment results reveal that the jitter noise suppression effect for the 1 PPS signal of the GNSS receiver using the proposed filtering scheme is better than that using commonly used Kalman filter. The 1 PPS output signal accuracy of the proposed time synchronous system reaches 1.17 ns, which is one order superior to the 1 PPS signal accuracy of GNSS receiver.
引文
[1] GONG F Y, SICHITIU M L. On the accuracy of pairwise time synchronization[J]. IEEE Transactions on Wireless Communications, 2017, 16 (4):2664- 2677.
[2] LIN L, ZHANG J L, MA M D, et al. Time synchronization for molecular communication with drift[J]. IEEE Communications Letters, 2017, 21(3):476- 479.
[3] ZHAN L W, LIU Y, YAO W X, et al. Utilization of chip-scale atomic clock for synchrophasor measurements[J]. IEEE Transactions on Power Delivery, 2016, 31(5):2299- 2300.
[4] CROSSLEY P A, GUO H, MA Z. Time synchronization for transmission substations using GPS and IEEE 1588[J]. Csee Journal of Power and Energy Systems, 2016, 2(3):91-99.
[5] ZHAO J C, ZHAN L W, LIU Y L, et al. Measurement accuracy limitation analysis on synchrophasors[C]. IEEE Power & Energy Society General, 2015:1- 5.
[6] 李保东,刘利,居向明,等. 卫星双向定时精度分析[J]. 时间频率学报, 2010, 33(2):129-133.LI B D, LIU L, JU X M, et al. Precision analysis of satellite two-way timing[J]. Journal of Time & Frequency, 2010, 33(2):129-133.
[7] 李铎,吴红卫,顾思洪. GPS驯服CPT原子钟方法研究[J]. 电子学报,2018, 46 (5):1194-1199.LI D, WU H W, GU S H. Study on GPS-disciplined CPT atomic clock[J]. Acta Electronica Sinica, 2018, 46(5):1194-1199.
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[9] SHMALIY Y S, KHAN S H, ZHAO S. General unbiased FIR filter with applications to GPS-based steering of oscillator frequency[J].IEEE Transactions on Control Systems Technology, 2017, 25(3):1141-1148.
[10] 张杰,周栋明. GPS驯服中无偏滑动平均滤波算法的研究[J].电子学报,2013,41(2):412- 416.ZHANG J, ZHOU D M. Improved moving average filter for GPS disciplined[J]. Acta Electronica Sinica, 2013, 41(2):412- 416.
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[12] 刘东辉,陈德智,孙晓云,等. 一种基于小波分析的除噪方法[J]. 仪器仪表学报,2000, 21(6):636- 637, 656.LIU D H, CHEN D ZH, SUN X Y, et al. A new denoise method using wavelet for ECT signals[J]. Chinese Journal of Scientific Instrument, 2000, 21(6): 636- 637, 656.
[13] TAVELLA P. Statistical and mathematical tools for atomic clocks[J]. Metrologia, 2008, 45(6):S183.
[14] 孟中, 甘至宏. 实时小波滤波器在空间相机像移速度滤波中的设计与实施[J]. 仪器仪表学报, 2013, 34(12):31-35.MENG ZH, GAN ZH H. The design and implementation of real-time wavelet filter on filtering for image movement velocity of space camera[J]. Chinese Journal of Scientific Instrument, 2013,34(12):31-35.
[15] ANGEL P, MORRIS C. Analyzing the mallat wavelet transform to delineate contour and textural features[J]. Computer Vision and Image Understanding, 2000, 80(3):267- 288.
[16] 宋丽君,蒋建虎. 小波阈值降噪中阈值函数族的一般构造方法[J]. 计算机工程与应用, 2017,53(19):236- 240.SONG L J, JIANG J H. General constructing method of function family in threshold de-noising based onwavelet[J]. Computer Engineering and Applications, 2017, 53(19):236- 240.
[17] LI Y H, LIU G Q, LI S Q. Synchronization system design of ground electromagnetic probe based on FPGA and GPS[J]. Advanced Materials Research, 2012(588- 589):1611-1614.
[18] 杨俊,陈智勇,余钫,等. 基于FPGA与TDC的GPS- 铷钟时间同步系统[J].宇航计测技术,2012,32(1):30-33.YANG J, CHEN ZH Y, YU F, et al. A GPS-Rubidium clock synchronization system based on FPGA and TDC[J]. Journal of Astronautic Metrology and Measurement, 2012, 32(1):30-33.
[19] ZUCCA C, TAVELLA P. A mathematical model for the atomic clock error in case of jumps[J]. Metrologia, 2003, 40(3):S257.
[20] IEEE Std. 1588- 2002 IEEE Standard for a precision clock sybchronization protocol for networked measurement and control systems[S]. 2002.
[2] LIN L, ZHANG J L, MA M D, et al. Time synchronization for molecular communication with drift[J]. IEEE Communications Letters, 2017, 21(3):476- 479.
[3] ZHAN L W, LIU Y, YAO W X, et al. Utilization of chip-scale atomic clock for synchrophasor measurements[J]. IEEE Transactions on Power Delivery, 2016, 31(5):2299- 2300.
[4] CROSSLEY P A, GUO H, MA Z. Time synchronization for transmission substations using GPS and IEEE 1588[J]. Csee Journal of Power and Energy Systems, 2016, 2(3):91-99.
[5] ZHAO J C, ZHAN L W, LIU Y L, et al. Measurement accuracy limitation analysis on synchrophasors[C]. IEEE Power & Energy Society General, 2015:1- 5.
[6] 李保东,刘利,居向明,等. 卫星双向定时精度分析[J]. 时间频率学报, 2010, 33(2):129-133.LI B D, LIU L, JU X M, et al. Precision analysis of satellite two-way timing[J]. Journal of Time & Frequency, 2010, 33(2):129-133.
[7] 李铎,吴红卫,顾思洪. GPS驯服CPT原子钟方法研究[J]. 电子学报,2018, 46 (5):1194-1199.LI D, WU H W, GU S H. Study on GPS-disciplined CPT atomic clock[J]. Acta Electronica Sinica, 2018, 46(5):1194-1199.
[8] 张帆, 胡永辉, 何在民. 一种基于GNSS的可驯频标的设计与实现[J]. 时间频率学报, 2013, 36(1):28-32, 53.ZHANG F, HU Y H, HE Z M. A design and implementation of disciplined clock based on GNSS[J]. Journal of Time & Frequency, 2013, 36(1):28-32, 53.
[9] SHMALIY Y S, KHAN S H, ZHAO S. General unbiased FIR filter with applications to GPS-based steering of oscillator frequency[J].IEEE Transactions on Control Systems Technology, 2017, 25(3):1141-1148.
[10] 张杰,周栋明. GPS驯服中无偏滑动平均滤波算法的研究[J].电子学报,2013,41(2):412- 416.ZHANG J, ZHOU D M. Improved moving average filter for GPS disciplined[J]. Acta Electronica Sinica, 2013, 41(2):412- 416.
[11] HELSBY N C. GPS disciplined offset-frequency quartz oscillator[C]. IEEE International Frequency Control Symposium and PDA Exhibition Jointly with the 17th European Frequency and Time Forum, 2003:435- 439.
[12] 刘东辉,陈德智,孙晓云,等. 一种基于小波分析的除噪方法[J]. 仪器仪表学报,2000, 21(6):636- 637, 656.LIU D H, CHEN D ZH, SUN X Y, et al. A new denoise method using wavelet for ECT signals[J]. Chinese Journal of Scientific Instrument, 2000, 21(6): 636- 637, 656.
[13] TAVELLA P. Statistical and mathematical tools for atomic clocks[J]. Metrologia, 2008, 45(6):S183.
[14] 孟中, 甘至宏. 实时小波滤波器在空间相机像移速度滤波中的设计与实施[J]. 仪器仪表学报, 2013, 34(12):31-35.MENG ZH, GAN ZH H. The design and implementation of real-time wavelet filter on filtering for image movement velocity of space camera[J]. Chinese Journal of Scientific Instrument, 2013,34(12):31-35.
[15] ANGEL P, MORRIS C. Analyzing the mallat wavelet transform to delineate contour and textural features[J]. Computer Vision and Image Understanding, 2000, 80(3):267- 288.
[16] 宋丽君,蒋建虎. 小波阈值降噪中阈值函数族的一般构造方法[J]. 计算机工程与应用, 2017,53(19):236- 240.SONG L J, JIANG J H. General constructing method of function family in threshold de-noising based onwavelet[J]. Computer Engineering and Applications, 2017, 53(19):236- 240.
[17] LI Y H, LIU G Q, LI S Q. Synchronization system design of ground electromagnetic probe based on FPGA and GPS[J]. Advanced Materials Research, 2012(588- 589):1611-1614.
[18] 杨俊,陈智勇,余钫,等. 基于FPGA与TDC的GPS- 铷钟时间同步系统[J].宇航计测技术,2012,32(1):30-33.YANG J, CHEN ZH Y, YU F, et al. A GPS-Rubidium clock synchronization system based on FPGA and TDC[J]. Journal of Astronautic Metrology and Measurement, 2012, 32(1):30-33.
[19] ZUCCA C, TAVELLA P. A mathematical model for the atomic clock error in case of jumps[J]. Metrologia, 2003, 40(3):S257.
[20] IEEE Std. 1588- 2002 IEEE Standard for a precision clock sybchronization protocol for networked measurement and control systems[S]. 2002.