微弱GPS信号捕获算法以及硬件实现
摘要
全球定位系统(NAVSTAR Global Positioning System, GPS)是美国在上世纪七十年代开始研制,于1994年全面建成的新一代卫星导航与定位系统,具有高精度、全天候、全覆盖等优点。在常见的交通、测绘、精确授时等领域都有着广泛的应用。
随着集成电路技术的突破性发展,微处理器和芯片集成度有了长足的进步,由专用硬件电路进行信号捕获的运算,可以极大的提高计算能力,降低功耗；由处理器判断运算结果、调整运算方案,可以提高整个捕获过程中的灵活性。所以在基带芯片中采用硬件运算和软件控制相结合的方式,是最有竞争力的方案。
本文首先介绍了GPS的基础知识,然后介绍了GPS技术中使用的扩频通信的信号特征和结构,并在此基础上介绍了常用于专用集成电路(Application Specific Integrated Circuits, ASIC)的线性滑动相关捕获算法。针对弱信号的特点,重点研究了所需时间短的频域循环相关捕获算法,相干积分和非相干积分运算对捕获性能的影响,以及在捕获微弱信号的过程中,长时间积分运算时进行码相位补偿对的重要性。在硬件电路实现的过程中,考虑到电路的复杂度和硬件资源,采用了平均采样的方法,降低了逻辑的复杂性,并且减小了电路面积。本课题中详细的给出了捕获硬件电路中各个模块的原理、功能以及仿真结果。捕获电路的功能和性能在现场可编程门阵列(Field Programmable Gate Array, FPGA)中得到了验证。本文在最后给出了捕获电路在台积电(TSMC) 65纳米的Low Power工艺库下的面积。
本文讨论的微弱GPS捕获算法普遍适用于的扩频通信的信号捕获,算法和实现方案,对研究下一代的导航定位系统,对“伽利略”或者“北斗”都有一定的借鉴意义。
GPS (NAVSTAR Global Positioning System) is began development in the last 70's by United States, built in 1994. It is a new generation satellite based navigation and positioning system, and has been widely used in transport, mapping, precise timing and other fields.
With the breakthrough in integrated circuit technology, especially microprocessors science and integration density, it is more and more popular to use microprocessor and dedicated acquisition logic in baseband chips. The use of microprocessor can increase the flexibility of the acquisition process, and the use of VLSI arithmetic logic can enhance the performance and cut off the power consumption.
The theory, structure and characteristic of GPS signal will be coverd in this paper. The methods of signal acquisition will be discussed, including serial search acquision, parallel frequency space search acquisition, coherent and incoherent integration, and C/A code phase compensation for weak singal.
The acquision party is implemented by logic, and described in block leve, and validated on the FPGA (Field Programmable Gate Array) platform. At last, the size and time report will be represent under the 65LP technology library of TSMC.
Weak GPS signal acquisition algorithm discussed in this article, which is well adapted to the direct sequence spread spectrum communication system, and has certain reference to the next generation satellite navigation and positioning system, such as "Galileo" and "Dipper"
随着集成电路技术的突破性发展,微处理器和芯片集成度有了长足的进步,由专用硬件电路进行信号捕获的运算,可以极大的提高计算能力,降低功耗；由处理器判断运算结果、调整运算方案,可以提高整个捕获过程中的灵活性。所以在基带芯片中采用硬件运算和软件控制相结合的方式,是最有竞争力的方案。
本文首先介绍了GPS的基础知识,然后介绍了GPS技术中使用的扩频通信的信号特征和结构,并在此基础上介绍了常用于专用集成电路(Application Specific Integrated Circuits, ASIC)的线性滑动相关捕获算法。针对弱信号的特点,重点研究了所需时间短的频域循环相关捕获算法,相干积分和非相干积分运算对捕获性能的影响,以及在捕获微弱信号的过程中,长时间积分运算时进行码相位补偿对的重要性。在硬件电路实现的过程中,考虑到电路的复杂度和硬件资源,采用了平均采样的方法,降低了逻辑的复杂性,并且减小了电路面积。本课题中详细的给出了捕获硬件电路中各个模块的原理、功能以及仿真结果。捕获电路的功能和性能在现场可编程门阵列(Field Programmable Gate Array, FPGA)中得到了验证。本文在最后给出了捕获电路在台积电(TSMC) 65纳米的Low Power工艺库下的面积。
本文讨论的微弱GPS捕获算法普遍适用于的扩频通信的信号捕获,算法和实现方案,对研究下一代的导航定位系统,对“伽利略”或者“北斗”都有一定的借鉴意义。
GPS (NAVSTAR Global Positioning System) is began development in the last 70's by United States, built in 1994. It is a new generation satellite based navigation and positioning system, and has been widely used in transport, mapping, precise timing and other fields.
With the breakthrough in integrated circuit technology, especially microprocessors science and integration density, it is more and more popular to use microprocessor and dedicated acquisition logic in baseband chips. The use of microprocessor can increase the flexibility of the acquisition process, and the use of VLSI arithmetic logic can enhance the performance and cut off the power consumption.
The theory, structure and characteristic of GPS signal will be coverd in this paper. The methods of signal acquisition will be discussed, including serial search acquision, parallel frequency space search acquisition, coherent and incoherent integration, and C/A code phase compensation for weak singal.
The acquision party is implemented by logic, and described in block leve, and validated on the FPGA (Field Programmable Gate Array) platform. At last, the size and time report will be represent under the 65LP technology library of TSMC.
Weak GPS signal acquisition algorithm discussed in this article, which is well adapted to the direct sequence spread spectrum communication system, and has certain reference to the next generation satellite navigation and positioning system, such as "Galileo" and "Dipper"
引文
[1]Elliott D.Kaplan著．寇艳红译，GPS原理与应用(第2版)[M]．北京：电子工业出版社,2007
[2]崔保延(美)著,陈军等译,GPS软件接收机基础(第2版)[M].北京：电子工业出版社,2007
[3]米斯拉(美),恩格(美)著,罗鸣等译,全球定位系统——信号、测量与性能[M].北京：电子工业出版社,2008
[4]南方测绘仪器有限公司.GPS培训班教材-GPS定位原理及应用.doc[EB],http://www.southsurvey. com/ 2010-05-23
[5]中国科技大学GPS实验室.GPS篇-正文[EB],http://www. eefocus. com/article/08-06/44206s. html 2010-05-24
[6]网络, GPS系统组成之GPS卫星[EB],http://www.gpsfield.com/principle/GPS%20System%20satellite. htm 2010-01-21
[7]P. Massat and M. Zeitzew, "The GPS constellation design - current and projected" [A] in Proceedings of ION National Technical Meeting 'Navigation 2000' [C]. Long Beach, California. January 21-23, 1998.
[8]北京麦格天宝科技发展有限公司技术支持部.GPS原理概述.ppt [EB], http://wenku. baidu. com/view/dca0a0254635eefdc8d33374. html 2010-05-22
[9]GPS报.挑战与机遇卫星导航的产业发展及现状 [EB],http://www. gpsbao. com/info/report/8266. html 2010-09-25
[10]Tsui, J. B Y. Microwave Receivers with electronic warfare applications[M].New York: Wiley, 1986
[11]Kai Borre, Dennis M. Akos, Nicolaj Bertelsen, Peter Rinder, Soren Holdt Jensen. A Software-Defined GPS and Galileo Receiver - A Single-Frequency Approach[M]. Boston · Basel · Berlin Birkhauser, 2007
[12]韩帅,导航接收机在弱信号下C/A码捕获技术研究[D],哈尔滨：哈尔滨工业大学,2007年7月
[13]周广宇,微弱GPS信号的捕获与跟踪处理的研究与实现[D],上海：上海 交通大学,2009年1月
[14]刘佳欣,扩频信号空域抗干扰滤波、码捕获的设计与FPGA实现[D],安徽：国防科技大学,2009年4月
[15]Skolnik, M. I. Introduction to radar systems[M]. New York: McGraw-Hill,1962
[16]Barton, D. K., Modern radar sysem analysis[M]. Norwood:Artech House,1988
[17]The SPIRENT, Inc. datasheet for STR4500 [EB]http://www.spirentfederal.com/GPS/Products/STR4500/Overvie w.2009-10-22
[18]The Maxim-IC, Inc. datasheet for MAX2769[EB] http://china.maxim-ic.com/datasheet/index.mvp/id/5241 2009-10-21
[19]The Dini Grop, Inc. datasheet for DN9200K10, [EB] http://www.dinigroup.com/DN9200k10PCI.php.2009-10-23
[20]The Xilinx, Inc. datasheet for Virtex-5. [EB] http://www.xilinx.com/products/virtex5/index.htm.2009-10-18
[21]陈涛,GPS接收机基带信号处理的研究和设计[D],上海：上海交通大学,2009年1月
[22]Tsui, James B. Y, Fundamentals of global positioning system receivers A Software Approach[M]. Hoboken:John Wiley & Sons, inc. 2005
[23]Luke Winternitz, Michael Moreau, Gregory J. Boegner, Sirotzky, Navigator GPS Receiver for Fast Acquisition and Weak Signal Space Applications[A]. ION GNSS Meeting[C], Long Beach, CA, September 21-24,2004.
[24]Dennis M. Akos, A SOFTWARE RADIO APPROACH TO GLOBAL NAVIGATION SATELLITE SYSTEM RECEIVER DESIGN[D]. Ohio:Ohio University,1997
[25]Mark L. Psiaki, Block Acquisition of Weak GPS Signals in a Software Receiver [A]. ION GPS 2001 [C],11-14 September 2001, Salt Lake City, UT
[26]Sanjeev Gunawardena, DEVELOPMENT OF A TRANSFORM-DOMAIN INSTRUMENTATION GLOBAL POSITIONING SYSTEM RECEIVER FOR SIGNAL QUALITY AND ANOMALOUS EVENT MONITORING[D]Ohio:Ohio University, 2007
[27]Dennis M. Akos, Per-Ludvig Normark, Jeong-Taek Lee, Konstantin G. Gromov, James B. Y. Tsui, John Schamus, LOW POWER GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS) SIGNAL DETECTION AND PROCESSING[A]. ION GPS 2000[C],19-22 September 2000, Salt Lake City, UT,784-791
[28]Cillian O'Driscoll, Performance Analysis of the Parallel Acquisition of Weak GPS Signals[D]Ireland:National University of Ireland,2007
[29]ZHEN ZHU, CHARACTERIZATION OF GLOBAL POSITIONING SYSTEM EARTH SURFACE MULTIPATH AND CROSS CORRELATION FOR AIRCRAFT PRECISION APPROACH OPERATIONS USING SOFTWARE RADIO TECHNOLOGY[D]Ohio:Ohio University,2006
[30]ZHEN ZHU, AVERAGING CORRELATION FOR WEAK GLOBAL POSITIONING SYSTEM SIGNAL PROCESSING[D]Ohio:Ohio University,2002
[31]The Mentor Graphics, Inc. datasheet for ModelSim [EB] http://www.mentor.com/products/fv/modelsim.2009-10-19
[32]The MathWorks, Inc. Communications toolbox. [EB] http://www.mathworks.com/products/communications.2009-10-20
[33]刘晓莉,李云荣,一种基于FFT的高动态GPS信号快速捕获方法[J],系统仿真学报.2007年5月,第19卷第10期,2151-2155
[34]何兴,GPS系统C/A码的产生与捕获算法的仿真与研究[J],中国科技论文在线
[35]蔡秀雄,刘瑞芹,张凤元,GPS微弱信号捕获算法[J],火力与指挥控制.2009年8月,第34卷第8期,105-107
[36]李玉红,寇艳红,张其善.微弱GPS信号捕获算法研究[J],遥测遥控.2005,26(4)：61-65.
[37]胡丛玮,李晓玲,安雷.一种改进的GPS微弱信号捕获方法[J],武汉大学学报,2008,33(8)：821-823.
[38]翟传润,张婧.GPS软件接收机微弱信号捕获算法研究[J],电子测量技术,2008,31(5)：137-140.
[39]杨兴,谢志远,戎丽,基于FPGA的FFT处理器设计[J],国外电子元器件,2008年第5卷
[40]鲍庆龙,刘平,基于FPGA的高速FFT算法实现[J],微处理机2007年第02期,16-18
[41]姜华,GPS接收机接收模块的研究与VLSI实现[D],上海：上海交通大学微电子学院,2008年1月
[42]王先毅,GPS软件接收机设计与弱信号处理[D],北京：中国科学院研究生院,2008年6月
[43]魏敬法,GPS信号快速捕获的FPGA实现[D],北京：中国科学院研究生院,2005年4月
[44]武丽静,高动态GPS接收机数控振荡器与捕获算法研究[D],北京：北京邮电大学,2009年2月
[45]梁丽芳,基于FPGA利用FFT算法实现GPS c/A码捕获的研究[D],大连：大连海事大学,2009年6月
[46]陈芬芬,基于FPGA的GPS接收机基带处理器的研究与设计[D],山西：中北大学,2009年5月
[47]李万强,卫星定位接收机捕获与跟踪算法的研究与实现[D],哈尔滨：哈尔滨工业大学,2008年12月
[48]深圳市华颖锐兴科技有限公司.GPS接收机灵敏度分析[EB],http://www.hellognss.com/tech/Receiver/2010-01-19/355.html 2010-01-20
[2]崔保延(美)著,陈军等译,GPS软件接收机基础(第2版)[M].北京：电子工业出版社,2007
[3]米斯拉(美),恩格(美)著,罗鸣等译,全球定位系统——信号、测量与性能[M].北京：电子工业出版社,2008
[4]南方测绘仪器有限公司.GPS培训班教材-GPS定位原理及应用.doc[EB],http://www.southsurvey. com/ 2010-05-23
[5]中国科技大学GPS实验室.GPS篇-正文[EB],http://www. eefocus. com/article/08-06/44206s. html 2010-05-24
[6]网络, GPS系统组成之GPS卫星[EB],http://www.gpsfield.com/principle/GPS%20System%20satellite. htm 2010-01-21
[7]P. Massat and M. Zeitzew, "The GPS constellation design - current and projected" [A] in Proceedings of ION National Technical Meeting 'Navigation 2000' [C]. Long Beach, California. January 21-23, 1998.
[8]北京麦格天宝科技发展有限公司技术支持部.GPS原理概述.ppt [EB], http://wenku. baidu. com/view/dca0a0254635eefdc8d33374. html 2010-05-22
[9]GPS报.挑战与机遇卫星导航的产业发展及现状 [EB],http://www. gpsbao. com/info/report/8266. html 2010-09-25
[10]Tsui, J. B Y. Microwave Receivers with electronic warfare applications[M].New York: Wiley, 1986
[11]Kai Borre, Dennis M. Akos, Nicolaj Bertelsen, Peter Rinder, Soren Holdt Jensen. A Software-Defined GPS and Galileo Receiver - A Single-Frequency Approach[M]. Boston · Basel · Berlin Birkhauser, 2007
[12]韩帅,导航接收机在弱信号下C/A码捕获技术研究[D],哈尔滨：哈尔滨工业大学,2007年7月
[13]周广宇,微弱GPS信号的捕获与跟踪处理的研究与实现[D],上海：上海 交通大学,2009年1月
[14]刘佳欣,扩频信号空域抗干扰滤波、码捕获的设计与FPGA实现[D],安徽：国防科技大学,2009年4月
[15]Skolnik, M. I. Introduction to radar systems[M]. New York: McGraw-Hill,1962
[16]Barton, D. K., Modern radar sysem analysis[M]. Norwood:Artech House,1988
[17]The SPIRENT, Inc. datasheet for STR4500 [EB]http://www.spirentfederal.com/GPS/Products/STR4500/Overvie w.2009-10-22
[18]The Maxim-IC, Inc. datasheet for MAX2769[EB] http://china.maxim-ic.com/datasheet/index.mvp/id/5241 2009-10-21
[19]The Dini Grop, Inc. datasheet for DN9200K10, [EB] http://www.dinigroup.com/DN9200k10PCI.php.2009-10-23
[20]The Xilinx, Inc. datasheet for Virtex-5. [EB] http://www.xilinx.com/products/virtex5/index.htm.2009-10-18
[21]陈涛,GPS接收机基带信号处理的研究和设计[D],上海：上海交通大学,2009年1月
[22]Tsui, James B. Y, Fundamentals of global positioning system receivers A Software Approach[M]. Hoboken:John Wiley & Sons, inc. 2005
[23]Luke Winternitz, Michael Moreau, Gregory J. Boegner, Sirotzky, Navigator GPS Receiver for Fast Acquisition and Weak Signal Space Applications[A]. ION GNSS Meeting[C], Long Beach, CA, September 21-24,2004.
[24]Dennis M. Akos, A SOFTWARE RADIO APPROACH TO GLOBAL NAVIGATION SATELLITE SYSTEM RECEIVER DESIGN[D]. Ohio:Ohio University,1997
[25]Mark L. Psiaki, Block Acquisition of Weak GPS Signals in a Software Receiver [A]. ION GPS 2001 [C],11-14 September 2001, Salt Lake City, UT
[26]Sanjeev Gunawardena, DEVELOPMENT OF A TRANSFORM-DOMAIN INSTRUMENTATION GLOBAL POSITIONING SYSTEM RECEIVER FOR SIGNAL QUALITY AND ANOMALOUS EVENT MONITORING[D]Ohio:Ohio University, 2007
[27]Dennis M. Akos, Per-Ludvig Normark, Jeong-Taek Lee, Konstantin G. Gromov, James B. Y. Tsui, John Schamus, LOW POWER GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS) SIGNAL DETECTION AND PROCESSING[A]. ION GPS 2000[C],19-22 September 2000, Salt Lake City, UT,784-791
[28]Cillian O'Driscoll, Performance Analysis of the Parallel Acquisition of Weak GPS Signals[D]Ireland:National University of Ireland,2007
[29]ZHEN ZHU, CHARACTERIZATION OF GLOBAL POSITIONING SYSTEM EARTH SURFACE MULTIPATH AND CROSS CORRELATION FOR AIRCRAFT PRECISION APPROACH OPERATIONS USING SOFTWARE RADIO TECHNOLOGY[D]Ohio:Ohio University,2006
[30]ZHEN ZHU, AVERAGING CORRELATION FOR WEAK GLOBAL POSITIONING SYSTEM SIGNAL PROCESSING[D]Ohio:Ohio University,2002
[31]The Mentor Graphics, Inc. datasheet for ModelSim [EB] http://www.mentor.com/products/fv/modelsim.2009-10-19
[32]The MathWorks, Inc. Communications toolbox. [EB] http://www.mathworks.com/products/communications.2009-10-20
[33]刘晓莉,李云荣,一种基于FFT的高动态GPS信号快速捕获方法[J],系统仿真学报.2007年5月,第19卷第10期,2151-2155
[34]何兴,GPS系统C/A码的产生与捕获算法的仿真与研究[J],中国科技论文在线
[35]蔡秀雄,刘瑞芹,张凤元,GPS微弱信号捕获算法[J],火力与指挥控制.2009年8月,第34卷第8期,105-107
[36]李玉红,寇艳红,张其善.微弱GPS信号捕获算法研究[J],遥测遥控.2005,26(4)：61-65.
[37]胡丛玮,李晓玲,安雷.一种改进的GPS微弱信号捕获方法[J],武汉大学学报,2008,33(8)：821-823.
[38]翟传润,张婧.GPS软件接收机微弱信号捕获算法研究[J],电子测量技术,2008,31(5)：137-140.
[39]杨兴,谢志远,戎丽,基于FPGA的FFT处理器设计[J],国外电子元器件,2008年第5卷
[40]鲍庆龙,刘平,基于FPGA的高速FFT算法实现[J],微处理机2007年第02期,16-18
[41]姜华,GPS接收机接收模块的研究与VLSI实现[D],上海：上海交通大学微电子学院,2008年1月
[42]王先毅,GPS软件接收机设计与弱信号处理[D],北京：中国科学院研究生院,2008年6月
[43]魏敬法,GPS信号快速捕获的FPGA实现[D],北京：中国科学院研究生院,2005年4月
[44]武丽静,高动态GPS接收机数控振荡器与捕获算法研究[D],北京：北京邮电大学,2009年2月
[45]梁丽芳,基于FPGA利用FFT算法实现GPS c/A码捕获的研究[D],大连：大连海事大学,2009年6月
[46]陈芬芬,基于FPGA的GPS接收机基带处理器的研究与设计[D],山西：中北大学,2009年5月
[47]李万强,卫星定位接收机捕获与跟踪算法的研究与实现[D],哈尔滨：哈尔滨工业大学,2008年12月
[48]深圳市华颖锐兴科技有限公司.GPS接收机灵敏度分析[EB],http://www.hellognss.com/tech/Receiver/2010-01-19/355.html 2010-01-20