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.
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.
作者
宋捷
鲁祖坤
陈飞强
于美婷
孙广富
SONG Jie;LU Zukun;CHEN Feiqiang;YU Meiting;SUN Guangfu(College of Electronic Science and Technology,National University of Defense Technology,Changsha 410073,China)
出处
《全球定位系统》
CSCD
2021年第4期106-112,共7页
Gnss World of China
基金
国家自然科学基金(62003354)。
