基于扩频理论软件接收机的研究
|
摘要
本论文将介绍一种软件模拟硬件的方法来实现PCM-CDMA-BPSK中频信号的快捕、跟踪和解调。关于扩频信号的传统的研究是在理想的条件下，比如低码率、窄动态范围、窄频率变化范围等等。对高动态、高码率、低信噪比、大多普勒及变化的码长和码率的扩频信号的快捕是本文的难点。
在扩频信号的捕获过程中要求有较小的时延和较高的概率，本文介绍一种二维信号的捕获方法，这种方法结合伪PN码和载波频率的获取，捕获时延将大幅度降低，实际上，扩频信号的检测是接收系统的关键。本文介绍一种通过积累能量新方法来改善输入信号的信噪比从而改善检测性能。
接收机稳定可靠地跟踪被捕获信号保证成功解调是必要的，本文介绍一种改善的锁相环设计方法，这种方法采用自适应参数和变带宽跟踪技术来调整输入信号改善捕获和跟踪性能。捕获和跟踪的性能指标：伪随机信号码率1M～5M比特/秒，码长是255、511，接收灵敏度是-118dB，信号动态范围是70dB载波普勒是±75kHz，目标捕获在0.2秒内。
In this thesis, a kind of software method is researched to realize the functions of fast acquisition , tracking and demodulation of PCM-CDMA-BPSK intermediate frequency signals.Conventional research on spread spectrum signals is in the case of ideal conditions, such as low code rate , narrow dynamic range , narrow frequency-changing range and so on. The specialities and difficulties of spread spectrum signals in this thesis are high dynamic. high code rate. low signal-to-nosie radio. wide Doppler range. varied code length, varied code rate, which have more difficulties.
Little acquisition time and high acquisition probability are required during the capturing process of spread spectrum signals. In this thesis, a kind of 2-dimention signal acquisition method is presented which combines parallel PN code phase and carrier frequency acquisition, as a result the acquisition time is shortened greatly. Besides, according to the fact that the detection of spread spectrum signals is always the key point in the receiving system. A new method is presented in this thesis by which accumulates the energy to improve the signal-to-nosie ratio of input-signals, consequently improve the detection performance.
It is necessary that the receiver tracks the acquired signals steadily and credibly to ensure the successful demodulation process. In this thesis, an improved tracking loop design method is presented which adopts self-adaptation parameters and varied bandwidth tracking technique to adapt to the input signals, and improves the acquisition and tracking performance.
The performance targets of acquisition and tracking: the code rate of pseudorandom signals is 1M-5MHz, the code length is 255. 511, the receiving sensitivity is -118dBm,the dynamic range is 70dB. the Doppler of carrier is 75kHz,
the time that 10 targets are captured within 0.2s.
在扩频信号的捕获过程中要求有较小的时延和较高的概率，本文介绍一种二维信号的捕获方法，这种方法结合伪PN码和载波频率的获取，捕获时延将大幅度降低，实际上，扩频信号的检测是接收系统的关键。本文介绍一种通过积累能量新方法来改善输入信号的信噪比从而改善检测性能。
接收机稳定可靠地跟踪被捕获信号保证成功解调是必要的，本文介绍一种改善的锁相环设计方法，这种方法采用自适应参数和变带宽跟踪技术来调整输入信号改善捕获和跟踪性能。捕获和跟踪的性能指标：伪随机信号码率1M～5M比特/秒，码长是255、511，接收灵敏度是-118dB，信号动态范围是70dB载波普勒是±75kHz，目标捕获在0.2秒内。
In this thesis, a kind of software method is researched to realize the functions of fast acquisition , tracking and demodulation of PCM-CDMA-BPSK intermediate frequency signals.Conventional research on spread spectrum signals is in the case of ideal conditions, such as low code rate , narrow dynamic range , narrow frequency-changing range and so on. The specialities and difficulties of spread spectrum signals in this thesis are high dynamic. high code rate. low signal-to-nosie radio. wide Doppler range. varied code length, varied code rate, which have more difficulties.
Little acquisition time and high acquisition probability are required during the capturing process of spread spectrum signals. In this thesis, a kind of 2-dimention signal acquisition method is presented which combines parallel PN code phase and carrier frequency acquisition, as a result the acquisition time is shortened greatly. Besides, according to the fact that the detection of spread spectrum signals is always the key point in the receiving system. A new method is presented in this thesis by which accumulates the energy to improve the signal-to-nosie ratio of input-signals, consequently improve the detection performance.
It is necessary that the receiver tracks the acquired signals steadily and credibly to ensure the successful demodulation process. In this thesis, an improved tracking loop design method is presented which adopts self-adaptation parameters and varied bandwidth tracking technique to adapt to the input signals, and improves the acquisition and tracking performance.
The performance targets of acquisition and tracking: the code rate of pseudorandom signals is 1M-5MHz, the code length is 255. 511, the receiving sensitivity is -118dBm,the dynamic range is 70dB. the Doppler of carrier is 75kHz,
the time that 10 targets are captured within 0.2s.
引文
1．[美)J．K霍姆斯著，梁振兴，蔡开基译．相干扩展频谱系统．国防工业出版社．1985：468～499，488
2．查光明，熊焦祚，扩频通信．西安电子科技大学出版社。1990：142～152
3．樊昌信，詹道庸，徐柄祥．吴成柯．通信原理(第四版)．北京：国防工业出版社．1995：141～147
4．沈允春，扩频技术．国防工业出版社．1995：2～15
5．张厥盛，郑继禹等．锁相技术．西安电子科技大学出版社．1994：64～66
6．沈凤麟，叶中付，钱玉美．信号统计分析与处理．中国科学技术大学出版社．2001：232～237
7．[美]Wichael J．Yong著，邱仲潘等译．Visual C.6从入门到精通．电子工业出版社．1991
8．[美]H．L范特里斯．检测、估计和调制理论．(卷Ⅰ)，国防工业出版社．1983：307～313
9．卢满宏．扩频信号快捕算法的研究与实例．硕士论文：43～53
10．Duane Hanselman，Bruse Littlefield，李人厚等译．精通MATLAB．西安交通大学出版社．1998：208～210
11．查光明，潘孟菡．M序列优选对的计算机实现及平衡GOLD码组．成都电讯工程学报．增刊(2)．1985．23～25
12 谢京稳，郭军海．遥外测综合测量系统弹道计算方法．遥测遥控．2000．VOL．21：5～11
13．仰书耀．扩频通信系统的码同步．南京航空学院学报．1981：1
14．谈振辉，关皓．DS—CDMA系统的载波和伪码同步技术．2001
15．郭伟，余敬东．直接序列扩频通信信号的检测．通信学报 1993：383～385
16．王忠，刘晓玲，任苏萍．高动态GPS接收机动态性能分析与改善途
径．全球定位系统．1999．2：7～13
17．刘守翠，高速直接序列扩频多址通信解扩技术．全国第四届军事通信学术会议．1994．10：34～36
18．魏安全．扩频码的同步捕捉与跟踪．军事通信技术．1998．3
19．陆奔，郭经红，尤肖虎．CDMA移动通信中部分并行的PN全局捕获．第五届全国青年学术论文集：10～11
20．刘雅娟．直接序列扩频通信伪码同步的研究．无线电通信．第25卷．第1期(总第147期)：57～58
21 邱永红，甘仲民．扩频卫星通信系统软件仿真的研究．微波与通信．第1期．1999．2：78～81
22．朱近康．扩频通信的频谱相关检测方法．通信学报．1998．12：8～9
23. Dr. Roland E. Best. Phase-lock loops:147～180
24. Niclsen P. T. on the Acquisition Behavior of Binary DILL,IEEE Vol. AES-11,P. 415-418,MAY 1975:32～36
25. R. C. Dixon,Spread spectrum Systems. (Second Edition). New York, 1984:234～245
26. Rob Shepherd. Engineering the Embedded Software Radio. IEEE Communication Magzine,Nov. 1999:76
27. Modulation and processing gain tradeoffs in DS-CDMA Spread Spectrum System[会，英]/Asano,D. K&hayashi T. //1998. IEEE 5th International Symposion on Spread Spectrum Techniques&Applications. Vol. 1 of 3-9-13(MAV):45～49
28. J. F. Kuehls and E. Geraniotis,"Presence Detection of Binary-Phase-Shifr-Keyed and Direct-Sequence Signals Using a Prefilter-Delay-and-Multiply Deveice" . IEEE Journal ON SAC,Vol. B. June 1990:915～933
2．查光明，熊焦祚，扩频通信．西安电子科技大学出版社。1990：142～152
3．樊昌信，詹道庸，徐柄祥．吴成柯．通信原理(第四版)．北京：国防工业出版社．1995：141～147
4．沈允春，扩频技术．国防工业出版社．1995：2～15
5．张厥盛，郑继禹等．锁相技术．西安电子科技大学出版社．1994：64～66
6．沈凤麟，叶中付，钱玉美．信号统计分析与处理．中国科学技术大学出版社．2001：232～237
7．[美]Wichael J．Yong著，邱仲潘等译．Visual C.6从入门到精通．电子工业出版社．1991
8．[美]H．L范特里斯．检测、估计和调制理论．(卷Ⅰ)，国防工业出版社．1983：307～313
9．卢满宏．扩频信号快捕算法的研究与实例．硕士论文：43～53
10．Duane Hanselman，Bruse Littlefield，李人厚等译．精通MATLAB．西安交通大学出版社．1998：208～210
11．查光明，潘孟菡．M序列优选对的计算机实现及平衡GOLD码组．成都电讯工程学报．增刊(2)．1985．23～25
12 谢京稳，郭军海．遥外测综合测量系统弹道计算方法．遥测遥控．2000．VOL．21：5～11
13．仰书耀．扩频通信系统的码同步．南京航空学院学报．1981：1
14．谈振辉，关皓．DS—CDMA系统的载波和伪码同步技术．2001
15．郭伟，余敬东．直接序列扩频通信信号的检测．通信学报 1993：383～385
16．王忠，刘晓玲，任苏萍．高动态GPS接收机动态性能分析与改善途
径．全球定位系统．1999．2：7～13
17．刘守翠，高速直接序列扩频多址通信解扩技术．全国第四届军事通信学术会议．1994．10：34～36
18．魏安全．扩频码的同步捕捉与跟踪．军事通信技术．1998．3
19．陆奔，郭经红，尤肖虎．CDMA移动通信中部分并行的PN全局捕获．第五届全国青年学术论文集：10～11
20．刘雅娟．直接序列扩频通信伪码同步的研究．无线电通信．第25卷．第1期(总第147期)：57～58
21 邱永红，甘仲民．扩频卫星通信系统软件仿真的研究．微波与通信．第1期．1999．2：78～81
22．朱近康．扩频通信的频谱相关检测方法．通信学报．1998．12：8～9
23. Dr. Roland E. Best. Phase-lock loops:147～180
24. Niclsen P. T. on the Acquisition Behavior of Binary DILL,IEEE Vol. AES-11,P. 415-418,MAY 1975:32～36
25. R. C. Dixon,Spread spectrum Systems. (Second Edition). New York, 1984:234～245
26. Rob Shepherd. Engineering the Embedded Software Radio. IEEE Communication Magzine,Nov. 1999:76
27. Modulation and processing gain tradeoffs in DS-CDMA Spread Spectrum System[会，英]/Asano,D. K&hayashi T. //1998. IEEE 5th International Symposion on Spread Spectrum Techniques&Applications. Vol. 1 of 3-9-13(MAV):45～49
28. J. F. Kuehls and E. Geraniotis,"Presence Detection of Binary-Phase-Shifr-Keyed and Direct-Sequence Signals Using a Prefilter-Delay-and-Multiply Deveice" . IEEE Journal ON SAC,Vol. B. June 1990:915～933