The local carrier optimization technology in anti-jamming satellite navigation receiver
-
摘要: 载波数字振荡器(NCO)是导航接收机中对接收信号进行载波剥离处理的关键部分. 在接收机的基带数字信号处理模块中,NCO通过量化位宽和地址字长分别对本地载波信号的幅值和频率进行量化,即通过存储器数据的位宽和深度设计本地载波. 在给定输入信号/干扰动态范围下,根据本地载波的特点,优化设计了载波NCO中只读存储器(ROM)的幅值量化位宽和地址字长,使其适应实际工程需求,在保证信噪比(SNR)损耗和频率误差的条件下避免了本地载波存储的冗余. 实验结果表明:从需求出发设计导航接收机本地载波的最优位宽和深度,可保证数字下变频SNR损耗小于0.1 dB,本地载波实际输出频率相对误差小于0.1%,且最优位宽和深度小于优化前,减小了存储资源占用率,有效地提高了本地载波输出信号在动态信号和干扰下的适应性.
-
关键词:
- 全球卫星导航系统(GNSS)接收机 /
- 本地载波 /
- 量化位宽 /
- 地址字长 /
- 参数优化
Abstract: Carrier numerically controlled oscillator (NCO) is a key part of the navigation receiver to strip the carrier of the received signal. In the digital signal processing module, the numerically controlled oscillator quantizes the amplitude and frequency of the local carrier signal through the quantization width and addressing word. The local carrier is designed by the bit width and depth of the memory data. Under the dynamic range of given input signal/interference, this paper optimizes the design of the quantization width and addressing length of the read-only memory (ROM) in the NCO according to the characteristics of the local carrier, adapting it to the actual engineering requirement, which avoids the redundancy of local carrier storage while ensuring the performance of signal-to-noise ratio (SNR) and frequency accuracy. The experimental results show that designing the optimal quantization width and addressing word of the navigation receiver local carrier based on the requirements can ensure the digital down-conversion SNR ratio loss less than 0.1 dB, the relative error of the actual output frequency of the local carrier less than 0.1%, and the optimal quantization width and addressing word less than the value before optimization. The storage resource occupancy rate was reduced, and the adaptability of the local carrier signal under dynamic signals and interference was effectively improved. -
表 1 量化位宽优化分析
输入SNR/dB 平均值 标准差 −20 3.17 0.465 8 0 3.55 0.431 8 10 4.73 0.562 7 30 8.14 0.808 5 50 11.22 0.314 7 表 2 量化位宽优化前后分析
dB 输入SNR 优化前SNR损耗 优化后SNR损耗 N=3 N=7 N=15 −20 0.077 6 0.063 6 0.061 5 0.047 0 0.112 9 0.064 5 0.069 7 0.069 10 0.540 7 0.071 0 0.073 0 0.053 30 11.247 5 0.181 8 0.071 2 0.052 50 30.907 2 7.148 0 0.067 2 0.051 表 3 量化位宽典型场景分析
dB 输入SNR SNR损耗 B=8 B=12 优化后 −20 0.027 6 0.014 0 0.017 0 −10 0.020 2 0.014 7 0.092 5 0 0.016 6 0.016 2 0.015 5 10 0.014 1 0.014 9 0.003 7 20 0.038 4 0.014 8 0.000 9 30 0.009 0 0.015 3 0.011 8 40 0.075 3 0.013 7 0.065 0 50 0.494 2 0.016 6 0.092 1 表 4 数据长度参数优化
数据长度/ms ${J_o}$ ${\delta _{f1}}$/% ${T_{{\rm{sum}}} }$/s 0.1 7 0.081 0 0.256 3 0.5 7 0.014 4 1.552 0 1.0 6 0.019 6 4.723 9 2.0 7 0.024 9 14.913 5 5.0 5 0.015 1 167.240 0 表 5 地址字长优化数据及性能分析
${f_o}$/Hz ${J_o}$ ${\delta _{f{\rm{1}}}}$/% ${\delta _{f{\rm{2}}}}$/% ${f_{ {J_o} } }$ 2 000 2 9.875 00 0.006 83 2 197.35 20 000 2 1.302 50 0.004 94 20 261.50 100 000 4 0.299 50 0.005 15 100 295.00 240 000 2 0.085 42 0.009 37 240 182.50 1 000 000 3 0.004 80 0.005 30 1 000 005.00 5 000 000 3 0.002 19 0.002 93 4 999 963.00 8 000 000 2 0.002 46 0.000 00 8 000 197.00 10 000 000 4 0.017 70 0.000 00 10 001 770.00 12 000 000 3 0.016 67 0.000 00 12 002 000.00 14 000 000 3 0.016 43 0.000 00 14 002 300.00 15 000 000 2 0.032 93 0.004 93 14 995 800.00 15 240 000 2 0.000 21 0.009 77 15 241 602.00 表 6 地址字长优化前后分析
${f_o}$/Hz ${\delta _{f{\rm{1}}}}$/% ${\delta _{f{\rm{2}}}}$/% 优化前 优化后 优化前 优化后 2 000 9.875 00 9.867 50 0.000 00 0.006 83 20 000 1.302 50 1.307 50 0.000 00 0.004 94 100 000 0.288 05 0.295 00 0.012 11 0.005 15 240 000 0.091 88 0.076 04 0.025 19 0.009 37 1 000 000 0.000 50 0.000 50 0.005 30 0.005 30 5 000 000 0.000 74 0.000 74 0.002 93 0.002 93 8 000 000 0.002 46 0.002 46 0.000 00 0.000 00 10 000 000 0.020 03 0.017 70 0.037 72 0.000 00 12 000 000 0.016 67 0.016 67 0.000 00 0.000 00 14 000 000 0.016 43 0.016 43 0.000 00 0.000 00 15 000 000 0.026 64 0.028 00 0.006 29 0.004 93 15 240 000 0.022 87 0.010 51 0.023 61 0.009 77 表 7 地址字长典型场景分析
本地载波标准频率/MHz 频率相对误差/% J=12 优化后 12.0 0.1116 0.1117 12.5 0.0680 0.0772 13.0 0.0346 0.0346 13.5 0.0741 0.0741 14.0 0.0857 0.0854 14.5 0.0690 0.0759 15.0 0.0300 0.0340 15.5 0.0886 0.0884 -
[1] 张亮, 贾小林, 王海春, 等. 北斗三号基本系统伪距单点定位性能分析[J]. 全球定位系统, 2019, 44(6): 20-26. [2] 陈星全. 新体制卫星导航系统的软件接收机的研究与实现[D]. 成都: 电子科技大学, 2020. [3] LI Z, ZHANG T S, QI F R, et al. Carrier phase prediction method for GNSS precise positioning in challenging environment[J]. Advances in space research, 2019, 63(7): 2164-2174. DOI: 10.1016/j.asr.2018.12.015 [4] 王飞雪, 郭桂蓉. 基于二阶采样的免混频全数字化正交解调[J]. 电子学报, 1999, 27(6): 118-119. DOI: 10.3321/j.issn:0372-2112.1999.06.026 [5] 刘春雅, 冯向莉. 基于CORDIC算法的数控振荡器及其FPGA实现[J]. 自动化与仪器仪表, 2015(8): 131-133. [6] 梁锦江. 快速锁定全数字锁相环的研究与设计[D]. 成都: 电子科技大学, 2020. [7] WANG Y, YANG R, MORTON Y T. Kalman filter-based robust closed-loop carrier tracking of airborne GNSS radio-occultation signals[J]. IEEE transactions on aerospace and electronic systems, 2020, 56(5): 3384-3393. DOI: 10.1109/TAES.2020.2972248 [8] 杨凯, 黄海生, 邢永强. GPS接收机中数控振荡器电路的设计[J]. 信息技术, 2017(9): 58-61, 66. [9] 陈造, 郑庆敏. FPGA方法用于GPS/北斗双模接收机基带处理模块设计[J]. 测绘技术装备, 2019, 21(4): 25-29. [10] 杨晓昆, 徐沛虎, 胡强, 等. 一种高精度卫星导航模拟器本地数字中频载波生成方法[J]. 现代导航, 2019, 10(4): 258-261. DOI: 10.3969/j.issn.1674-7976.2019.04.005 [11] LU Z K, CHEN H M, CHEN F Q, et al. Blind adaptive channel mismatch equalisation method for GNSS antenna arrays[J]. IET radar, sonar and navigation, 2018, 12(4): 383-389. DOI: 10.1049/iet-rsn.2017.0416 [12] DAI X Z, NIE J W, CHEN F Q, et al. Distortionless space-time adaptive processor based on MVDR beamformer for GNSS receiver[J]. IET radar, sonar and navigation, 2017, 11(10): 1488-1494. DOI: 10.1049/iet-rsn.2017.0168 [13] 吴远斌, 李景文. 直接中频采样及数字相干检波的研究[J]. 电子学报, 1994, 22(10): 105-107. DOI: 10.3321/j.issn:0372-2112.1994.10.020 [14] LU Z K, NIE J W, WAN Y D, et al. Optimal reference element for interference suppression in GNSS antenna arrays under channel mismatch[J]. IET radar, sonar and navigation, 2017, 11(7): 1161-1169. DOI: 10.1049/iet-rsn.2016.0582 [15] 陈飞强, 聂俊伟, 苏映雪, 等. 载波相位辅助的卫星导航天线阵抗干扰算法[J]. 国防科技大学学报, 2015, 37(6): 69-73, 83. DOI: 10.11887/j.cn.201506014 [16] NIE J W, CHEN F Q, WANG F X, et al. Distortionless space-time adaptive processor for global navigation satellite system receiver[J]. Electronics letters, 2015, 51(25): 2138-2139. DOI: 10.1049/el.2015.2832 [17] 庞晶, 牟卫华, 唐小妹, 等. 相位量化误差对导航模拟信号伪距生成精度的影响分析[J]. 全球定位系统, 2014, 39(6): 6-10. [18] 刘征岳. 北斗导航接收机基带信号处理技术研究与实现[D]. 桂林: 桂林电子科技大学, 2014. [19] 孙爱晶, 党薇, 吉利萍. 通信原理[M]. 北京: 人民邮电出版社, 2013: 215-217. [20] WEN L S, LIANG X, ZHONG J, et al. Oscillation of the NCO model[J]. Physica a: statistical mechanics and its applications, 2012, 391(11): 3300-3307. DOI: 10.1016/j.physa.2011.12.039 [21] 曹广利, 宋茂忠. 卫星导航接收机中载波和码NCO的研究与实现[J]. 应用科技, 2012, 39(1): 1-4. DOI: 10.3969/j.issn.1009-671X.201108009 [22] 张阿宁, 赵萍. 基于FPGA的正交数控振荡器(NCO)的设计与实现[J]. 电子设计工程, 2011, 19(17): 149-152. DOI: 10.3969/j.issn.1674-6236.2011.17.054 [23] 吴兴存, 何谦, 殷雪明, 等. GNSS接收机中载波和伪码NCO的设计[J]. 电讯技术, 2011, 51(4): 79-83. DOI: 10.3969/j.issn.1001-893x.2011.04.017 [24] 黄旭伟. DDS杂散抑制技术研究[D]. 重庆: 重庆大学, 2007. [25] 黄旭伟, 吴玉成. 一种降低DDS相位截断误差的方法[J]. 信息与电子工程, 2007, 5(2): 142-146. DOI: 10.3969/j.issn.1672-2892.2007.02.015