基于扩频测控系统的关键技术设计与实现
发布时间：2018-11-23 15:54
【摘要】：扩频通信作为近年来迅速发展的一种通信技术,由于其抗干扰性能好、保密性高、高精度测距等特点,在军用通信和民用通信中得到了广泛的应用。本文对扩频测控中的关键技术扩频信号的捕获和同步进行了研究,并将其运用到国内某弹载应答机中。由于弹载应答机的信号处理模块芯片资源有限,在对传统匹配滤波器捕获法的捕获性能和占用资源进行软件仿真和分析后,引出了数字差动滤波器捕获法。通过仿真和分析,该方法在完全不影响捕获性能的前提下,能够节省将近一半的硬件逻辑资源和功耗,是很值得在扩频测控系统中使用的方法。由于地面信号和弹载应答机之间的相对高速运动会产生很大的多普勒频偏,使用普通的锁相环进行载波跟踪将非常困难。本文提出了一种叉积自动频率跟踪算法和二阶锁频环辅助三阶锁相环相结合的载波跟踪方法,对其进行软件仿真和硬件测试。再使用码环的载波辅助技术提高跟踪精度,并给出具体设计方案。对其进行实测和分析后,该环路在载噪比为27dB·Hz时,能够对信号进行精确跟踪。最后,在弹载应答机上使用FPGA实现了本文提出的扩频信号捕获和同步设计,给出实际测量结果:系统捕获时间为1.8s,测量伪距均值为5802.5ns,标准差为0.19ns,方差为0.0361ns2。测量精度高,满足技术指标要求。
[Abstract]:Spread spectrum communication, as a rapidly developing communication technology in recent years, has been widely used in military and civil communications because of its good anti-jamming performance, high confidentiality and high precision ranging. This paper studies the acquisition and synchronization of spread spectrum signal, which is the key technology of spread spectrum measurement and control, and applies it to a domestic missile transponder. Because of the limited chip resources of the signal processing module of the missile transponder, the acquisition performance of the traditional matched filter capture method and the resource occupation are simulated and analyzed by software, and the digital differential filter acquisition method is introduced. The simulation and analysis show that this method can save nearly half of the hardware logic resources and power consumption without affecting the acquisition performance at all. It is worth using in the spread spectrum measurement and control system. Because the relative high speed motion between the ground signal and the missile transponder will produce a very large Doppler frequency offset, it will be very difficult to track the carrier by using the ordinary phase-locked loop (PLL). In this paper, an automatic frequency tracking algorithm based on cross product and a carrier tracking method based on second-order frequency locked loop aided third-order phase-locked loop are proposed. The software simulation and hardware test are carried out. The tracking accuracy is improved by using the carrier-assisted technique of the code loop, and the specific design scheme is given. After the measurement and analysis, the loop can track the signal accurately when the carrier to noise ratio is 27dB Hz. Finally, the acquisition and synchronization design of spread spectrum signals proposed in this paper is realized by using FPGA on the missile transponder. The actual measurement results are as follows: the acquisition time of the system is 1.8s, the mean of measurement pseudo-range is 5802.5ns, and the standard deviation is 0.19ns. The variance was 0.0361nS2. The measurement accuracy is high and meets the requirement of technical index.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN914.42
[Abstract]:Spread spectrum communication, as a rapidly developing communication technology in recent years, has been widely used in military and civil communications because of its good anti-jamming performance, high confidentiality and high precision ranging. This paper studies the acquisition and synchronization of spread spectrum signal, which is the key technology of spread spectrum measurement and control, and applies it to a domestic missile transponder. Because of the limited chip resources of the signal processing module of the missile transponder, the acquisition performance of the traditional matched filter capture method and the resource occupation are simulated and analyzed by software, and the digital differential filter acquisition method is introduced. The simulation and analysis show that this method can save nearly half of the hardware logic resources and power consumption without affecting the acquisition performance at all. It is worth using in the spread spectrum measurement and control system. Because the relative high speed motion between the ground signal and the missile transponder will produce a very large Doppler frequency offset, it will be very difficult to track the carrier by using the ordinary phase-locked loop (PLL). In this paper, an automatic frequency tracking algorithm based on cross product and a carrier tracking method based on second-order frequency locked loop aided third-order phase-locked loop are proposed. The software simulation and hardware test are carried out. The tracking accuracy is improved by using the carrier-assisted technique of the code loop, and the specific design scheme is given. After the measurement and analysis, the loop can track the signal accurately when the carrier to noise ratio is 27dB Hz. Finally, the acquisition and synchronization design of spread spectrum signals proposed in this paper is realized by using FPGA on the missile transponder. The actual measurement results are as follows: the acquisition time of the system is 1.8s, the mean of measurement pseudo-range is 5802.5ns, and the standard deviation is 0.19ns. The variance was 0.0361nS2. The measurement accuracy is high and meets the requirement of technical index.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN914.42
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6 谢建全;谢R，
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