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电表信号功耗低、扩频序列较短,因此在低信噪比和多普勒频偏下实现突发信号的精准捕获是接收机设计的重点。针对部分匹配滤波-快速傅里叶变换(PMF-FFT)算法非相干积累后信噪比增益不足的问题,引入了一种基于频域差分非相干的PMF-FFT算法,消除了非相干平方损耗对捕获增益的影响;进一步结合通信环境提出了一种改进频域差分非相干算法,研究对突发直接序列扩频信号的捕获,实现智能电表接收端无线信号的粗同步。仿真实验表明,在消耗相同计算资源的情况下,改进算法的信噪比增益高于传统非相干积累法。 相似文献
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GPS(Global Positioning System)接收机中,常用的捕获方法有时域串行捕获方法、基于FFT( Fast Fourier Transform)的并行频率捕获方法和基于FFT的并行码相位捕获方法,但在某些应用场景下,会对卫星信号的捕获速度提出更高的要求,因此给出了一种基于相关的SFFT(Sparse Fast Fourier Transform)的卫星信号快速捕获算法。该算法结合卫星信号伪随机码的强自相关性的特性,将原有的SFFT的幅度估值去掉,利用时域串行的捕获方法,将SFFT算法中输出的大值坐标点对应的本地伪码与接收卫星信号做相关,进而捕获卫星信号。通过实验对算法进行验证,并与已有的卫星信号捕获方法进行对比,结果表明该方法能有效地运用于卫星信号捕获中,并且该算法的运算量要比传统捕获算法更低。 相似文献
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设计在高动态环境下工作的GPS接收机,其难点之一便在于对卫星伪码的快速捕获。针对缩短GPS接收机捕获伪随机码时问的问题,在对GPS信号结构作出分析的前提下,解释了时域滑动相关的常规捕获方法;提出了基于FFT的快速捕获技术,并在Marlab环境下做了系统仿真,仿真结果显示捕获速度可以得到显著提高。 相似文献
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高动态GPS接收机研究的核心是信号的捕获与跟踪算法,在接收机硬件实现时,系统性能与资源消耗直接受捕获算法的影响。结合时域滑动相关法和基于FFT的频域捕获算法各自的优点,提出一种基于伪码互相关特性的快速捕获算法,在不影响系统性能的前提下,既加快了捕获速度,又降低了资源消耗,实现了捕获速度和资源消耗二者的平衡。 相似文献
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PN码捕获技术是扩频通信的关键技术之一,针对扩频通信中长伪码序列的快速捕获问题,伪码相位大范围不确定的搜索,串行捕获需要大量的时间,这对实时性要求高的扩频接收机用户是无法忍受的,并行捕获电路结构比较复杂,实现起来有一定的难度,而且占用大量的资源。文中提出了一种基于FPGA的扩频信号快速滑动相关捕获方法,来解决低信噪比条件下长伪码序列的捕获问题。文中着重论述了该系统的FPGA实现原理,并且基于FPGA进行开发,调制出了该系统的仿真波形,达到了理想的效果,实际应用中有效地改善了系统的性能。 相似文献
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信号捕获是全球定位系统(global positioning syetem,GPS)接收机的关键技术,本文对GPS中的串行、匹配滤波和并行伪码相位三种捕获算法进行了理论分析,同时针对捕获算法的捕获时间、捕获运算量、占用资源以及捕获结果进行了对比分析和仿真验证。仿真分析表明:三种捕获算法均能有效捕获GPS信号,它们各有优缺点但并行伪码相位捕获方案更适合大规模推广,使用价值高。 相似文献
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The authors present a new digital matched filter architecture: digital differential matched filter (DDMF), that employs novel schemes to reduce the number of multiplications and accumulations (M and A). Theoretical analysis shows that the DDMF saves half of the M and A hardware in comparison with the conventional filter, and maintains identical processing gain. This makes the proposed DDMF more suitable for direct sequence spread spectrum (DSSS) communication systems and low power VLSI implementations 相似文献
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本文在分析匹配滤波器的工作原理及制约数字匹配滤波器性能的主要参数后,在文献[5]所给出折叠匹配滤波器的基础上设计了一种改进的折叠匹配滤波器结构,该结构具有更好的可实现性和更少的FPGA资源消耗。该设计已经应用于某型号中频数字化直接序列扩频接收机中,并取得了满意的效果。 相似文献
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匹配滤波器的多相实现 总被引:1,自引:0,他引:1
本文介绍了匹配滤波器在直接序列扩频通信系统的同步捕获中的应用,研究了数字匹配滤波器的实现方法,提出了基于多相分解的实现结构。与传统的直接实现形式和折叠滤波器等改进形式相比,多相形式具有占用资源少的优点。 相似文献
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扩频信号的捕获与跟踪是扩频接收机进行定位解扩的基础,文中基于FPGA进行了扩频信号捕获与跟踪的设计实现。分析了该方案的匹配滤波器、载波跟踪环、码跟踪环的设计与实现方法。并通过BPSK调制,使用非相干扩频通信的PN码并行捕获算法实现信号的捕获。 相似文献
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Ching-Hung Chiou Chao-Wang Huang Kuei-Ann Wen Mau-Lin Wu 《Selected Areas in Communications, IEEE Journal on》2001,19(11):2142-2150
A programmable pipelined digital differential matched filter (PDMF) implemented for a direct sequence spread spectrum receiver is proposed in this paper. To reduce the power consumption, the PDMF architecture is based on the synchronization combined PN code phase acquisition algorithm. Compared with the conventional PN code phase acquisition algorithm, the theoretical analysis result indicates that the PDMF acquires both power efficient and preferable detection. Depending on different applications, programmability allows the PDMF to implement 3-tap, 5-tap, or 11-tap Barker codes with the same hardware but different precisions for each tap coefficient. For short tap Baker codes, the architecture could adopt more precision on each tap coefficient to resist the channel noise. Simulation results also show that there are fewer errors of high sample precision with the same tape 相似文献
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The design of receiver architectures for use in direct sequence spread spectrum systems is reviewed. As it is difficult to construct the long matched filters for these systems, the authors propose a programmable receiver architecture which achieves the required high processing gain while, at the same time, simplifying the filter hardware requirements. Results are presented for a prototype receiver, based on digital signal processing (DSP) components, which can be reprogrammed for serial, serial-parallel or fully parallel operation while offering minimal degradation from theoretical performance 相似文献
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Puska H. Saarnisaari H. Iinatti J. Lilja P. 《Communications, IEEE Transactions on》2008,56(2):299-308
This paper investigates three code acquisition methods for direct sequence spread spectrum systems (DS/SS) utilizing smart antennas. The methods are suitable especially for receivers that consist of a smart antenna followed by a single correlator or a matched filter (IMF). The first method is the known fixed beam strategy where the whole angular uncertainty region is divided into small cells using conventional beamforming techniques. Therein, the receiver searches through all angular and delay cells via a serial search procedure. In the second method, the fixed division is made using advanced beamforming techniques, which provide improved tolerance against interference. In the third strategy, the direction-of-arrival (DOA) of incoming signals are estimated and utilized in the acquisition process. An advantage of this DOA estimation-based strategy, when compared to fixed beamforming methods, is a decrease in the region of uncertainty. Disadvantages are increased computational complexity and signal-to-noise ratio (SNR) limitations. The acquisition strategies are compared when the serial search acquisition of the code phase is made using either the correlator or the matched filter. The results indicate that a single antenna receiver gives the best acquisition performance when SNR is high. However, single antenna methods are sensitive to interference. On the other hand, DOA estimation-based methods offer shorter mean acquisition times than fixed beam methods, especially when the number of arriving signals is small. 相似文献