共查询到19条相似文献,搜索用时 250 毫秒
1.
在合理选择通信系统参量和通信信道参量的基础上,利用MonteCarlo方法模拟了卫星接收到的水下平台上行激光通信信号.分析了卫星接收信号的空间和时间分布特性,以及与望远镜接收视场角的关系,并计算了接收信号的信噪比,得出了3°望远镜视场角和15μs信号积分时间的优化参量.基于计算结果,根据激光脉冲的PPM调制方式和最大似然检测方法,计算了系统的通信误码率,同时分析了海气界面、云等传输介质对通信的影响.研究结果表明:根据文中给定通信系统参量,在典型海水、海气界面、云等环境条件下,卫星与激光信号中心水平距离5km范围内信号误码率10-4.因此位于水下60m的水下平台可能实现对卫星上行激光通信. 相似文献
2.
星载激光对水下目标通信可行性研究 总被引:10,自引:0,他引:10
简要分析了通信信道中各传输介质的特性,确定了合理的传输介质光学参量。并根据一定的通信系统参量,利用蒙特卡罗方法模拟了水下目标接收信号的时间和空间分布。蒙特卡罗估计误差与平均值比值的上限小于0.3%。根据模拟的结果,得出了优化的接收系统采样时隙和接收望远镜视场角,进而计算了接收信噪比。在此基础上,基于激光脉冲的脉冲位置调制(PPM)方式和最大似然检测,计算出通信系统的误码率。研究结果表明,在较恶劣环境条件下,利用星载激光系统可以实现对水下目标的良好通信。 相似文献
3.
《中国光学与应用光学文摘》2007,(1)
TN929.12007010738星载激光对水下目标通信可行性研究=Feasibility studyof laser communications from satellite to submerged plat-form[刊,中]/刘金涛(中科院上海精密机械所先进激光技术与应用系统实验室.上海(201800)),陈卫标//光学学报.—2006,26(10).—1441-1446分析了通信信道中各传输介质的特性,确定了合理的传输介质光学参量。根据一定的通信系统参量,利用蒙特卡罗方法模拟了水下目标接收信号的时间和空间分布。蒙特卡罗估计误差与平均值比值的上限小于0.3%。根据模拟结果,得出了优化的接收系统采样时隙和接收望远镜视场角,进而… 相似文献
4.
根据大气激光通信传输方程和黑体辐射理论提出了计算激光引信中接收光学系统接收视场的方法,通过接收视场确定了接收光学系统的初始结构参数,设计了焦距为15 mm,视场角为2ω≮±7°的柱透镜光学系统.采用倒置法,将线阵CCD探测器置于准直物镜的焦面上接收信号,解决了接收光学系统后截距过短无法安置线阵CCD的问题,扩大了测量范围,又保证了精度,测量误差为1%.针对激光引信的结构特点,设计了测量激光引信接收光学系统视场角的自动测试系统.实验测试结果表明该引信的视场角都在合格范围内,重复精度≤5%,满足设计的要求. 相似文献
5.
6.
激光引信接收光学组件的研究与测试 总被引:1,自引:0,他引:1
根据大气激光通信传输方程和黑体辐射理论提出了计算激光引信中接收光学系统接收视场的方法,通过接收视场确定了接收光学系统的初始结构参数,设计了焦距为15 mm,视场角为2ω≮±7°的柱透镜光学系统.采用倒置法,将线阵CCD探测器置于准直物镜的焦面上接收信号,解决了接收光学系统后截距过短无法安置线阵CCD的问题,扩大了测量范围,又保证了精度,测量误差为1%.针对激光引信的结构特点,设计了测量激光引信接收光学系统视场角的自动测试系统.实验测试结果表明该引信的视场角都在合格范围内,重复精度≤5%,满足设计的要求. 相似文献
7.
为了评估大气湍流对机载激光通信系统的影响,理论分析和数值计算了机载激光通信链路中传输光场的二阶特性,包括接收光斑尺寸、光斑偏移量、光束相干半径、光束到达角起伏。计算结果表明:大气湍流对空间激光通信系统的影响主要在低空对流层,并随着机载平台高度的增加而降低。由于受到低空大折射率结构常数的影响,上行链路的接收光斑尺寸、光斑漂移量比下行链路大。下行链路光束到达角抖动比上行链路大,其值为若干rad。提出的模型及计算结果,可以为机载激光通信系统设计及性能评估提供参考。 相似文献
8.
9.
10.
11.
提出了一种新的多进制无线光通信技术,其基本原理是用一组相互易区分的空间图案代替传统无线通信中的会聚光斑传递信息.分析了该通信方案的信道容量,结果表明无线光通信系统存在未被利用的空间自由度,其大小与系统收发孔径和光波波长有关,与光场空间分布无关.通过合理设置系统的结构参数和设计信号图案,可以利用无线光通信系统的空间自由度增加信道容量.提出了一种实现该技术的光电系统方案,其关键组成部分为空间光调制器和图象相关器.详细描述了信号处理过程,具体包括二维相关处理、比较判决和进制转换三部分.分析了该方案的误码性能,得到了平均误码率的估算公式,分析得到了可降低误码率的信号设计基本规则.最后用一个透镜阵列处理器通过实验验证了该通信方案. 相似文献
12.
For 6G and future communication technologies, integration of navigation and communication has become a hot research topic, which can greatly improve the transmission data rate and can be applied to self-driving vehicles. In former research, a novel integrated navigation and communication signal has been designed by combining traditional global navigation satellite system (GNSS) and cyclic code shift keying (CCSK) signals. In this paper, we design an enhancement strategy for this signal, optimizing the number of cyclic shifts of the CCSK signal, which can make larger values of cross-correlation function align with the peak value of self-correlation function to overcome the cross-correlation interference and improve communication performance. Simulation results validate that the proposal not only can avoid interference between navigation and communication signals, but also can improve the signal detection probability and reduce the transmit error rate. Taking Beidou B1I signal as an example, when the signal to noise ratio (SNR) is set to -27 dB, the detection probabilities for the navigation and communication signals increase about 11.4% and 13.5%, respectively, while the symbol error rate (SER) for the navigation and communication signals decrease about 16.3% and 17.8%, respectively. 相似文献
13.
A novel full-duplex radio-over-fiber system is proposed and demonstrated, in which an external modulator and an optical interleaver are used to generate dual octupling-frequency optical millimeter waves for two base stations and wavelength reuse for uplink connection. This scheme is simplified and low-cost because no additional laser is utilized for uplink connection at two base stations and one laser at central office works for two base stations simultaneously. The frequency of local oscillator signal is reduced largely due to frequency octupling. The theorem about how to generate optical millimeter waves is analyzed. The simulation results show that the bidirectional 5 Gb/s system has a perfect performance because the power penalty for the downlink and uplink signals of two base stations are less than 0.6 dB after successful transmission over 60 km standard single mode fiber. 相似文献
14.
In this paper, we analyze the outage probability of the radio over intersatellite optical wireless communication system in the presence of satellite vibration with bias error. The lower-based Mach–Zehnder modulator, optical booster amplifier and optical preamplifier are employed. First, the models of the proposed system and channel are given. Then the outage probability for a given bit error ratio (BER) of a quadrature phase shift keying signal is obtained in the presence of satellite vibration with bias error. Numerical results of outage probability with different bias error and average BER are given. Results indicate that the outage probability is obviously influenced by the pointing error and the optimum telescope diameter to minimize the outage probability exists. With the same pointing error condition, the value of the optimal telescope diameter will increase with the reduction of the given average BER. 相似文献
15.
Wenhe Du Feizhan Chen Zhongmin Yao Ruibo Ai Daosen Liu Quanling Cui 《Journal of Russian Laser Research》2013,34(4):351-355
In satellite–ground laser communications, atmospheric turbulence in the link degrades the performance of the system, so it is very important to estimate its influence on the performance of the system. The bit-error rate (BER) is an important parameter to indicate the communication performance of the system, which is directly used to judge the quality of the communication system. Using the results of our two previous papers, we analyze the joint influence of Kolmogorov turbulence from the ground up to 6 km and non-Kolmogorov turbulence above 6 km on the BER. These kinds of turbulence are associated respectively with the uplink and the downlink propagation channels for the geosynchronous orbit satellite communication system. 相似文献
16.
单光子源通常采用基于高斯光束的高度衰减激光脉冲,假设激光束具有初始高斯时域脉冲波形和TEM01模拉盖尔-高斯空域分布.基于折射率起伏的Rytov近似和修正von Karman谱模型,研究了大气湍流对星地量子通信单光子捕获概率的影响;建立了上行信道和下行信道的单光子捕获概率理论模型;针对低轨卫星-地面站间激光链路,对单光子捕获概率进行了分析.结果表明:上行信道的单光子捕获概率强烈依赖于地面折射率结构常数C2n(0),且随着C2n(0)的增加而减小;然而,下行信道的单光子捕获概率并不依赖于C2n(0),即大气湍流对其没有影响. 相似文献
17.
Wenhe Du Hengjun Zhu Daosen Liu Zhongmin Yao Chengjiang Cai Xiufeng Du Ruibo Ai 《Journal of Russian Laser Research》2012,33(5):456-463
In the past half a century, satellite laser communication has caught the attention of scientists due to its distinct advantages in comparison with conventional satellite microwave communication. For ground-to-satellite and satellite-to-ground data links, the atmosphere is a part of the communication channel; thus, atmospheric turbulence severely degrades the performance of satellite laser communication systems. In general, the Kolmogorov turbulence model is used to study the effect of atmosphere turbulence on satellite laser communications since it has been confirmed by numerous direct measurements of temperature and humidity fluctuations in the atmospheric boundary layer. However, increasing experimental evidence and theoretical investigations have shown that the Kolmogorov theory is sometimes inadequate to describe atmospheric statistics properly, in particular, in some domains of the atmosphere. We analyze the joint influence of Kolmogorov turbulence from the ground to 6 km and non-Kolmogorov turbulence above 6 km on the spot size associated with the uplink and downlink propagation channels for a satellite laser communication system in the geosynchronous orbit, using a power spectrum of non-Kolmogorov turbulence with power law ?5 that describes the refractiveindex fluctuations in the atmosphere above 6 km and considering the combined power spectrum of Kolmogorov and non-Kolmogorov turbulence. Before this analysis, we study the joint influence of the Kolmogorov turbulence from the ground to 6 km and non-Kolmogorov turbulence above 6 km on the scintillation indices of laser beams. 相似文献
18.
Hong Wen 《Optics Communications》2008,281(8):2083-2088
In this paper, we present a full-duplex radio-over-fiber system incorporating both optical millimeter-wave (mm-wave) generation and wavelength reuse for uplink connection. The optical double sidebands (DSB) signal is generated by using only one inexpensive broadband direct modulation laser (DML), to which a mixing RF signal is applied. An optical interleaver is then used to separate the first-order optical sidebands from the optical carrier of optical DSB signal. The separated first-order optical sidebands are beat to generate mm-wave signal that has double the frequency of the RF drive signal, while the separated optical carrier is reused as light source to remodulate uplink signal. Both detailed theoretical analysis and experiments to demonstrate the feasibility of the proposed system are presented. Experiment result shows that the bidirectional 2.5 Gb/s data can be successfully transmitted over 40 km standard single-mode fiber (SSMF) with less than 2 dB power penalty. 相似文献
19.
为了研究地星上行和星地下行激光链路孔径内接收光强信号的典型特征,基于大气湍流理论和位相屏方法,计算了短波和中波红外激光在特定大气相干长度条件下,孔径内接收激光功率与总功率的比值及起伏情况。根据统计结果讨论了上下行大气通道传播特性的差异,结果表明相同外界条件下,直径50 cm孔径内接收的下行激光信号强度大于上行激光信号强度1个数量级以上,其信号的起伏程度也低于上行激光;中等湍流下,下行激光孔径接收光强的概率分布函数服从对数正态分布,最大概率接收功率比与无湍流条件下的功率比值一致,分别为0.42%(1.315 m)和 0.26%(3.8 m)。 相似文献