低轨星座短报文通信中的扩频信号二维快捕优化与实现

张军; 郑立荣; 林宝军; 沈苑; 龚文斌; 帅涛

doi:10.11728/cjss2021.06.976

低轨星座短报文通信中的扩频信号二维快捕优化与实现

doi: 10.11728/cjss2021.06.976 cstr: 32142.14.cjss2021.06.976

张军^1,2,3,
郑立荣¹,
林宝军^2,3,
沈苑^2,3,
龚文斌^2,3,
帅涛^3,4

1. 复旦大学信息科学与工程学院上海 200433;
2. 中国科学院微小卫星创新研究院上海 201203;
3. 中国科学院大学北京 100049;
4. 中国科学院上海天文台上海 200030

基金项目:

上海市科委课题项目资助（16511103000）

详细信息

作者简介:

张军,E-mail:zhangjun@microsate.com

中图分类号: TN927
计量
- 文章访问数: 947
- HTML全文浏览量: 157
- PDF下载量: 40
- 被引次数:
  0(来源:Crossref)
  
  0(来源:其他)
出版历程
- 收稿日期: 2020-08-14
- 修回日期: 2021-08-19
- 刊出日期: 2021-11-15

Optimization and Implementation of Two-dimensional Fast Acquiring DSSS Burst Datagram Communication for LEO Satellite Constellation

1. School of Information Science and Engineering, Fudan University, Shanghai 200433;
2. Innovation Academy for Microsatellites, Chinese Academy of Sciences, Shanghai 201203;
3. University of Chinese Academy of Sciences, Beijing 100049;
4. Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030

摘要

摘要: 极弱信号、大多普勒动态变化条件下的接收机抗干扰、快速捕获同步技术是低轨卫星短报文数据通信的研究难点.本文首先分析了多普勒特性对低轨卫星扩频信号快捕的影响，讨论了现有各种捕获策略的优缺点.在此基础上提出双倍采样、补零的部分匹配滤波与快速傅里叶变换相结合的二维并行快速捕获优化设计方案，并进行了性能仿真分析，最后结合面向判决的同步技术，给出接收机原理样机捕获时间的实现结果.在给定前导码条件下，优化后的二维并行捕获平均时间为10ms，远低于常规扩频码并行捕获的秒量级捕获时间，可以较好地满足低轨卫星星座全球短报文数据突发通信及随遇接入需求.
- 低轨卫星星座 /
- 短报文通信 /
- 快速捕获 /
- 直接序列扩频 /
- 快速傅里叶变换
Abstract: Large Doppler shifts and extremely weak signal in the condition of short datagram burst LEO satellite communication are always the technical challenges for fast acquisition receiver. Firstly, the influence of Doppler characteristics on the fast acquisition of LEO satellite spread spectrum signal is analyzed, and the advantages and disadvantages of different acquisition strategies are discussed. Based on double-sampling zero-padding technology of partial matched filter and Fast Fourier Transform (FFT), Optimization and implementation of two-dimensional parallel fast acquiring Direct Sequence Spread Spectrum (DSSS) signal processing method is presented. Different from the single sampling scheme in which the input signal is sampled according to the chip rate, the double sampling scheme has two sampling signals reaching the correlator in each chip time. That is, the correlator works on a clock with twice than the chip rate. The correlator selects a sampling signal at each interval and inputs it to the PN code part correlator for correlation operation, and then outputs the maximum value after passing through the FFT module and energy accumulation module for judgment. Therefore, the maximum sampling signal-to-noise ratio loss is about 0.9 dB, which greatly improves the performance compared with the single sampling method. Finally, combined with the decision oriented carrier forward estimation and PN code feedback synchronization technology, the actual test shows that the average acquisition time of the receiver is 10 ms, which is much lower than the tradition parallel acquisition time of PN sequence code in seconds order. It can better meet the service requirements of short datagram burst communication system with random access for LEO satellite constellation.
- Low-Earth Orbit (LEO) satellite constellation /
- Short datagram burst communication /
- Fast acquisition /
- Direct-Sequence Spread Spectrum (DSSS) /
- Fast Fourier Transform (FFT)

HTML全文

参考文献(17)

[1]	ZONG Ke, CAO Guixing, YAN Zhongwen. Development and application of data communication microsatellite constellation system[J]. Spacecraft Eng., 2011, 20(2):66-71(宗可, 曹桂兴, 闫忠文. 数据通信微小卫星星座系统的发展及应用[J]. 航天器工程, 2011, 20(2):66-71)
[2]	LIU Yang, LIU Wu, DAI Yuanyuan, et al. Optimization design of LEO short data communication constellation for emergency communication[J]. Modern Electron. Tech., 2019, 42(5):20-26(刘洋, 刘武, 戴媛媛, 等. 面向应急通信的低轨短数据通信星座优化设计[J]. 现代电子技术, 2019, 42(5):20-26)
[3]	YI Kechu, LI Yi, SUN Chenhua, et al. Recent development and its prospect of satellite communications[J]. J. Commun., 2015, 6:161-176(易克初, 李怡, 孙晨华, 等. 卫星通信的近期发展与前景展望[J]. 通信学报, 2015, 6:161-176)
[4]	LIU Yu, ZOU Guangnan, WANG Zhaojun, et al. Research on satellite short datagram communication system[J]. Radio Eng., 2014, 44(10):12-14(刘宇, 邹光南, 王兆俊, 等. 卫星短报文通信系统研究[J]. 无线电工程, 2014, 44(10):12-14)
[5]	LUO Jufeng, WANG Xiang, FU Yaoxian, et al. A new fast acquisition method of parallel search pseudo-code and frequency offset based on FFT[J]. J. Elect. Inf. Technol., 2011, 33(3):563-568(罗炬锋, 王翔, 付耀先, 等. 基于FFT并行搜索伪码和频偏的快速捕获新方法[J]. 电子与信息学报, 2011, 33(3):563-568)
[6]	DONG Zhihong, WU Siliang. New acquisition method for DSSS with large Dopple[J]. J. Syst. Eng. Elect., 2008, 30(8):1424-1426(董智红, 吴嗣亮. 大多普勒偏移下直接序列扩频信号捕获新方法[J]. 系统工程与电子技术, 2008, 30(8):1424-1426)
[7]	VITERBI A J. Principle of CDMA Spread Spectrum Communication[M]. Beijing:Posts and Telecom Press, 1997(VITERBI A J. CDMA扩频通信原理[M]. 北京:人民邮电出版社, 1997)
[8]	STIRLING-GALLACHER R A, HULBERT A P, POVEY G J R. A fast acquisition technique for a direct sequence spread spectrum signal in the presence of a large Doppler shift[C]//IEEE 4th International Symposium on. Spread Spectrum Techniques and Applications Proceedings. Mainz:IEEE, 1996
[9]	AKOPIAN D. Fast FFT based GPS satellite acquisition methods[J]. IEE Proc. Radar Sonar Nav., 2005, 152(4):277-286
[10]	LI Ju, CHEN He, JIN Junkun, et al. Two methods of rapid code acquisition based on FFT[J]. J. Elect. Inf. Technol., 2006, 28(10):1778-1781(李菊, 陈禾, 金俊坤, 等. 基于FFT的两种伪码快速捕获方案的研究与实现[J]. 电子与信息学报, 2006, 28(10):1778-1781)
[11]	WANG Airong, LEI Gang, YUE Sanchuang. An approach of acquiring spread spectrum signal and tracking frequency deviation under burst communication[J]. Fire Cont. Radar Technol., 2014, 43(4):56-59(王爱荣, 雷刚, 岳三创. 一种突发通信下扩频信号捕获及频偏跟踪方法[J]. 火控雷达技术, 2014, 43(4):56-59)
[12]	WANG Mengli, WANG Feixue. Estimation of satellite signal's propagation delay for fast and direct acquisition of long cycle and high rate pseudo-random code[J]. Chin. J. Space Sci., 2007, 27(3):253-257(王梦丽, 王飞雪. 长码快速直接捕获中卫星信号传播时延估计[J]. 空间科学学报, 2007, 27(3):253-257)
[13]	JIANG Wenbing. Research and Implementation of Satellite DSSS Short Burst Fast Demodulation Technology[D]. Nanjing:Nanjing University of Science & Technology, 2018:15-55(姜文兵. 卫星DSSS短突发快速解调技术研究和实现[D]. 南京:南京理工大学, 2018:15-55)
[14]	KAPLAN E D. Understanding GPS:Principles and Applications[M]. Beijing:Publishing House of Electronics Industry, 2002:124-125(KAPLAN E D. GPS原理与应用[M]. 北京:电子工业出版社, 2002:124-125)
[15]	FAN Chunlei, ZHU Qin. Noncoherent integration squaring-loss algorithm based on receiver operating characteristic curve[J]. Telecommun. Eng., 2012, 52(7):1169-1173(范春磊, 朱勤. 于接收机特性曲线的非相干积分平方损耗计算方法[J]. 电讯技术, 2012, 52(7):1169-1173)
[16]	CORAZZA G E. On the MAX/TC criterion for code acquisition and its application to DS-SSMA systems[J]. IEEE Trans. Commun., 1996, 44:1173-1182
[17]	SHUAI Tao, REN Qianyi, LIU Huijie, et al. Hybrid parallel PN code acquisition technique for LEO satellite spread spectrum communication[J]. J. Commun., 2007, 28(10):79-84(帅涛, 任前义, 刘会杰, 等. 低轨卫星扩频系统中的PN码混合并行捕获技术研究[J]. 通信学报, 2007, 28(10):79-84)