星座通信系统测控模式探讨

立足星座通信系统的测控观点,基于卫星自主管理和采用新的伪码扩频测控体制,探讨简化地面测控管理所必需完成的大量复杂跟踪测量与控制任务的可行性,研究星座通信系统测控管理的操作设想。     

无人机测控通信系统中智能天线技术

针对无人机测控与信息传输系统中地面设备笨重、跟踪速度慢等问题,提出地面天线采用智能天线的方法,利用MUSIC(MUltiple SIgnal Classification,多重信号分类)算法实现对机载终端的DOA(Direction Of Ar-rival,波达方向)估计,并添加去相关操作对抗多径,利用基于LCMV(Linearly Constrained Minimum Variance,线性约束最小方差)准则的波束成形算法完成波束赋形,相较于传统的机械跟踪方式,具有设备质量小、成本低、机动性灵活性强和跟踪速度快等优势.仿真和实际测试结果表明,采用DOA估计和波束成形算法的智能天线能够在保证高增益的同时,实时准确地估计出有用信号和多径信号的来波信号方向,并正确完成波束指向,具有很高的工程应用价值.     

Optimum and Suboptimum Synchronizer for Binary FSK Communication Systems

This paper considers a binary frequency-shift-keying (FSK) communication system with an adaptive receiver. Partially coherent detection is accomplished exploiting phase and bit synchronization directly extracted from the information-bearing waveform. The optimum (maximum a posteriori probability criterion) estimators of the relevant channel parameters are found along with some suboptimum realizations. It turns out that these schemes are decision-directed tracking systems that may be implemented using standard circuitry.     

Linear FM Signal Formats for Beacon and Communication Systems

This paper examines the capabilities of the class of linear FM spread-spectrum signals within the context of potential communications systems usage in order to establish some performance criteria and bounds that permit comparison with other spread-spectrum formats. A systematic basis is provided for parameter selection for this class of signals by examining the interaction a mong the frequency-modulation indices, time-bandwidth product, and cross-talk criteria that determine the number of effective linear FM signals (or channels) that can be used within the constraints of a bounded time-frequency region. A general expression is derived relating N, the number of useful signals, R2, a cross-talk parameter, ToWo, the mean time-bandwidth product, and ?max and ?min, the maximum and minimum FM rates of the signal set. Canonic signal processor structures are described for ensembles of linear FM signals that have either constant duration or constant bandwidth. It is then shown that the signal modulation format can be modified in accordance with classical paired-echo theory to expand the utility of this class of signals in both synchronous and nonsynchronous operations to yield the equivalent of time-division and code multiplexing. Possible applications for this signal format are discussed.     

近距离的无线通信系统的构建

首先介绍使用ET13X340/330无线通信芯片构建300MHz近距离无线通信平台的原理和方法,然后简介使用ET13X211/221无线通信芯片构建27MHz无线通信系统的方法,最后对这二种芯片的使用方法和效果作了讨论和比较.     

从CIDS,CMS看客舱通信系统的发展

介绍了Ａ－３４０ＣＩＤＳ系统及Ｂｏｅｉｎｇ－７７７ＣＭＳ系统，分析了客舱通信系统的现状及发展，为航空公司在机型改装及设备配置时提供参考     

Orbiting Platform Communication and Data Management Systems

The communications and tracking (C&T) system on board the orbiting platform communicates with the ground facilities through the TDRS satellites. The C&T system operates on Ku and S-band. Using a high gain antenna the Ku-band channel can support a downlink data rate of 300 Mbps through the TDRS single axis channel. The S-band system communicates with the orbiter and with both multiple and single axis TDRS channels. The Data Management System (DMS) provides the following services to the orbiting platform: data distribution within and between core systems and payloads, data processing facilities for core systems, data base management, time and frequency standards, and overall platform management and control. The DMS is a distributed data processing network. The nodes are connected by a local area network (LAN). Each node is autonomous. Since the design is modular, nodes can be added or deleted without disturbing the system. Sensors and effectors communicate with the core system software via the network through multiplexers/demultiplexers.     

Digital Communication Systems in Impulsive Atmospheric Radio Noise

Analyses are presented of the performance of binary and M-ary coherent and noncoherent communication systems operating in the impulsive atmospheric radio noise environment. The receiver is usually a maximum likelihood detector for white Gaussian interference and therefore has the form of a parallel bank of matched filters followed by decision circuitry. By employing a Poisson or generalized Shot noise model for the impulsive noise with a suitable probability density function (pdf), closed-form expressions and bounds of error probabilities for M-ary noncoherent and coherent amplitude-shift keying (ASK), phase-shift keying (PSK), and frequency-shift keying (FSK) systems are obtained and the results discussed.     

Protection of PSK Communication Systems with Adaptive Arrays

The performance of binary phase-shift-keyed (BPSK), binarydifferential phase-shift-keyed (DPSK), and quadrature phase-shift-keyed(QPSK) communication systems that use adaptive arrayantennas for interference rejection is examined. The case where thedesired signal is corrupted by continuous wave (CW) interference isspecifically addressed. The performance of the adaptive array andthe ideal BPSK, DPSK, and QPSK detectors are evaluated first andthe results of these calculations are combined to determine theoverall system performance. The bit-error probability at the systemoutput is used as the performance measure. Several examples arepresented which illustrate the effects of signal powers, arrivalangles, frequencies, and the array input bandwidth.     

一种串行通讯模块的ATS设计与实现

自动测试系统(ATS)广泛应用于各类产品(器件、部件、电路板、设备或系统)从设计、生产到使用维护的各个阶段.提出一套基于通讯模块测试的ATS的解决方案,体现了ATS模块化设计思想并提供了一种通用ATS的实现途径.对从事这方面的开发工作的读者会有所帮助.     

直接扩频通信系统中最小误码率准则下的特征相消器

首先研究最小误码率准则下的特征相消器,再由最小化误码率（MBER）准则和约束条件的最小均值输出能量（MMOE）准则之间存在的关系,将MBER准则下特征相消器的设计转化为约束条件的MMOE下的干扰抑制器的设计,并利用子空间跟踪算法实现MMOE准则下的干扰抑制器。仿真表明,采用子空间跟踪算法比同准则下的RLS算法有更低的计算量和更好的抗干扰效果。     

Optimal Utilization of Satellite Communication Systems through Supervisory Control

Users of satellite communication systems being designed are charcterized by diversity. System designers now have the capability of serving thousands of simultaneous users; the users need not all follow the same system parameters. Diversity and characteristics are shown, and an attempt is made to list all the parameters desired by users. Usage of satellite communications systems is projected to serve a maximum of 200 000 users by means of 10 multipurpose satellites. It is shown that a supervisory control system is necessary to achieve optimal utilization of the existing resources.     

卫星通信中16QAM信号的数字预失真研究

高阶信号通过功放时发生非线性失真,需对功放进行线性化补偿,功率回退法是最简单直接的线性化方法,但功放效率不高。数字信号处理技术的发展使得数字预失真技术成为补偿功放失真最有效的方式之一,在一定程度上促进了高阶调制信号在卫星通信中的应用,缓解频谱资源紧张问题。以16QAM信号为对象,着重研究了预失真器模型的两个关键因子——非线性阶数和记忆深度——对预失真性能的影响。仿真结果表明,相较于非线性阶数,记忆深度对预失真性能的影响更大;而且功率回退法和数字预失真方法的结合使用可以取得更好的预失真效果。     

Output Signal-to-Noise Ratios for Amplitude-Modulated Noise-Like Lasers

A general expression of the output SNR of a photodetector is derived for a noise-like laser amplitude-modulated by a stationary Gaussian random modulating signal in the presence of a background light. The electric field Vx(t) of the noise-like laser is assumed to be a stationary narrowband Gaussian random process with zero mean. Two types of modulating signal are considered, the baseband and bandpass modulating signals. More specifically, the effects of the center frequency of the modulating signal, the modulating degree, the bandwidth ration of the noise-like laser to the modulating signal, the effective average quantum rate, and input CNR on output SNR are studied. The detection characteristics of the noise-like laser are also made clear by comparison with the case of a coherent laser.     

设计模式在测控通信构件设计中的应用

为了有效缩短开发周期并提高软件质量,必须提升测控软件的复用性和可扩展性。针对实际通信软件开发中的僵化性问题,提出了使用设计模式进行构件化设计的思路。结合具体通信应用完成了可扩展通信构件的分解和设计,测控协议的更改周期从传统开发方式的数月缩减为几个工作日,测控软件的维护成本得以大幅降低。通过对通信构件搭建过程的逐步介绍可以看出,设计模式是大规模构件化结构设计的基础,能够解决航天测控软件中常见的突出问题。     

网络编码在无线通信系统物理层中的应用

在对网络编码技术概念及发展现状的研究基础上,分析网络编码在无线通信系统物理层中的应用,重点研究物理层网络编码技术以及网络编码与信道编码的联合设计,并进行综述.一方面,介绍物理层网络编码机制,对物理层网络编码的主要研究热点进行分类,包括物理层网络编码的编解码设计、同步问题、与其他传输技术的结合、信息容量分析以及应用场景扩展,总结现有成果及发展方向.另一方面,研究不同网络编码与信道编码联合设计方案,根据设计的不同角度,将其归纳为结合信道编码的类型、改造软信息处理的方式、利用物理层网络编码及考虑不同的系统场景.     

移动通信系统中扩频码的优选

本文通过对时分多址直接序列扩频移动通信系统中的扩频调制单元的研究,运用计算机模拟分析技术,对优选扩频码方案进行了论证,并重点讨论了选码过程中的部分相关性问题。最终获得了一组实用性较强的优选码组。     

航空电子系统分区间通信监控技术的研究和实现

当今基于ARINC653的综合化航空电子系统的应用日益广泛,分区作为ARINC653提出的任务调度和资源共享的核心概念,其相互间通信的可靠性和安全性成为航空电子系统要解决的重要问题.详细阐述了分区间通信监视的原理,并给出了一种可行的分区间通信监视器设计和实现方案.应用表明分区间通信监视器极大地改善和提高了航空电子系统的通信监控能力,为通信故障诊断和分析提供了依据.     

分区间通信在航空电子系统中的设计与实现

新一代航空电子系统是一种高度综合化、模块化的系统,为了确保系统工作的安全、可靠,必须有高安全性的实时操作系统支持。在高安全性的实时操作系统中提出了分区(Partition)的概念,原有的“子系统”概念已由硬件实体演变为软的“子系统”。分区是运行于一个处理机模块上的多个应用程序(或子系统),这些应用程序在时间和空间上彼此隔离,互不影响,当一个分区内的应用发生错误时,在时间和空间上都不会影响到别的分区的执行。为了适应分区间隔离的需要,应用程序之间的通信由传统的进程间通信方式变为分区间的通信方式,本文着重介绍了自主版权操作系统(ACoreOS653)中满足ARINC653要求的分区间通信的设计与实现方法。     

深空测控通信技术发展趋势分析

为满足21世纪我国深空探测任务的需要，参考国外深空测控通信系统的先进技术，归纳和总结了未来相关技术发展的7个趋势，为我国深空测控通信技术的发展提供一些参考。