共查询到19条相似文献,搜索用时 234 毫秒
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瞬时测频接收机通常工作在复杂的电磁环境中,宽带的接收特性使其极易受到影响。针对瞬时测频接收机的工作机理,选取了连续波信号、高占空比信号、同时到达信号、低截获概率雷达信号等典型雷达信号样式,对瞬时测频接收机产生的影响,分析引起工作性能下降的原因和现象,并对部分结论进行了仿真实验验证,得到了与分析结论一致的实验结果。对雷达侦察装备研制和使用具有一定的借鉴意义。 相似文献
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本文通过对ALENIA SIR-M型二次雷达的概述,分析了SIR-M接收机的信号流程,又对接收机中的重要组件对数中频LOG IF进行了详细的分析,并给出了故障维修实例,供民航各技术保障单位的雷达设备现场维护同行参考交流。 相似文献
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讨论了实现软件雷达接收机的理论基础;提出了实现软件接收机的硬件电路时存在的问题及解决方案;给出了几种雷达信号的基本解调方法. 相似文献
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针对国内毫米波宽带成像测量雷达的建设思路,从3个方面展开论述:首先,列举了国外相关雷达的主要技术指标,并对其技术特点进行分析,通过采用高功率发射机及功率合成技术、低损耗传输技术、低噪声接收机技术等,国外毫米波雷达实现了对远距离目标的探测,具备很高的测距测角精度、cm级的距离分辨率和极高的多普勒灵敏度,具有较强的目标识别能力;随后,通过对单脉冲机械跟踪和相控阵2种体制的优缺点进行比对分析,建议国内应采用单脉冲机械跟踪体制,并重点探讨了引导捕获和宽带测量方案;最后,对宽带大功率发射机、波束波导天馈线系统、宽带超导接收机以及宽带数据采集等关键技术及其国内基础进行了分析,并给出了发展建议。 相似文献
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那洪祥 《海军航空工程学院学报》2017,32(4):347-350, 364
介绍了一种基于DRFM的高分辨雷达扩展目标回波信号仿真方法,该方法将舰船等复杂目标视为扩展目标,其雷达回波信号可以看作扩展目标各散射中心产生的回波信号的叠加。应用该技术产生的模拟目标回波信号和假目标干扰信号,由于携带雷达发射信号和照射目标特征信息,能顺利进入末制导雷达接收机,仿真效果优于一般常规仿真技术。 相似文献
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介绍了多相滤波器组接收机的数学模型,讨论了该模型在软件化雷达接收系统中的应用,并给出了基于多相滤波器组接收机模型的软件化雷达接收系统的硬件结构. 相似文献
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探月工程对飞行器导航系统的性能提出了更高要求,因而有必要研究GNSS(Global Navigation Satellite System,全球导航卫星系统)接收机在探月任务中的应用。以探月工程三期为应用需求,开展地-月-地转移过程中的GNSS接收机可用性分析、GNSS信号特性分析;并针对低信噪比环境下的高灵敏度接收机系统应用进行设计,采用弱信号捕获算法和弱信号跟踪算法实现-175dBW的灵敏度;最终采用基于轨道动力学模型的卡尔曼滤波方法实现了GNSS自主定轨算法。仿真表明:GNSS接收机在60 000km以下的地-月转移和月-地转移弧段能够为探月飞行器提供100m以内位置精度的导航服务。 相似文献
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仅用地面雷达跟踪数据评估制导系统的精度,其效果受客观条件限制。研究表明,把GPS(全球定位系统)作为外测资源在精度分析工作中加以利用,则效益显著。本文探讨综合利用GPS和地面雷达测量数据评估制导系统精度的问题。即对飞行试验的导弹,除了采用地面雷达进行跟踪测量外,还假设其装有弹载接收机。该高动态接收机通过弹载天线接收从四颗(以上)卫星发射的信号,该信号提供伪距和伪距变化率数据及广播星历资料。将这些外测数据(GPS数据和雷达数据)与遥测信息结合起来,选定合适的状态参数后,即可建立状态方程和观测方程。本文采用先进的估计技术(尤指U-D型卡尔曼滤波器)可分离出制导系统惯性器件等误差。由于把导弹的遥测速度和位置(修正了已知误差)转化成相应的外测数据并与之求差产生观测量,同时形成相应的测量矩阵。而U-D型卡尔曼滤波器又能将观矢量进行标量化处理,因此综合利用GPS数据和地面跟踪数据,实际上增大了观测矢量的阶数,从而提高了状态估计精度。当仅有其中一种测量手段时,该滤波器仍能正常运算。 相似文献
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Moyer L.R. Maciel L.J. Brown R.D. Little M.O. Wicks M.C. Weiner D.D. 《Aerospace and Electronic Systems Magazine, IEEE》1993,8(10):10-14
A technique that effectively reduces the dynamic range of the input signal in a radar receiver prior to digitization is presented. The dynamic range reduction is accomplished through a process that predicts the next radar return signal from the previous return signals, generates a replica waveform, and subtracts this replica waveform from the radar return signal prior to digitization. This process allows the radar return signal to be digitized without distortion by an analog-to-digital converter (ADC) having a limited dynamic range. The full dynamic range of the radar return signal is then restored by adding the replica waveform to the ADC output. Test and evaluation results using both synthetic and recorded radar data demonstrate in excess of a 30-dB reduction in the dynamic range of the signal at the ADC input when strong clutter is present 相似文献
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The receiver signal of a general angle tracking radar where there is asingle target which consists of a set of n reflectors is analyzed. It is shown how the analysis of this radar can be greatly simplified by representing the signals in the receiver as complex variables. This representation also makes it very easy to analyze such problems as scintillation and single-sideband crosstalk. 相似文献
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Hershey J.E. Schroeder J.E. 《IEEE transactions on aerospace and electronic systems》1990,26(5):732-736
A technique for performing altimetric functions (and possibly very-low-resolution imaging radar) without the transmission of a signal is suggested. The system could benefit an invasive aerospace platform that needs to remain totally electronically silent. The concept uses naturally occurring galactic noise as the illumination signal. A rapid and low-cost processor is also suggested. The results developed are also useful for the particular case of low probability of intercept (LPI) radar in which the transmitter emits a broadband Gaussian-like signal and the receivers cannot locally generate the transmitted reference. Another derivation of the arcsine law is provided along with a measure of its efficiency compared with an optimal receiver 相似文献
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分析了准连续波三通道雷达接收机的特点,提出了一种先进的雷达数字信号处理机的实现方案。该方案采用了中频采样、高速 DSP和并行体系结构等先进技术。在系统实现层次上,分析了一些中频采样实现方法的局限,进而提出了适合准连续波雷达回波特点的采样滤波器的设计方法和采样频率选择公式。在硬件设计上,本系统采用了32位浮点 DSP--ADSP21060和相应的并行结构。 相似文献
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The effective weighting function for weather radar is defined. This weighting function considers the effects of both the transmitted signal and the receiver filter. It is used to assign effective ranges to samples taken at prescribed times. For uniformly distributed targets it is shown that "signal"-to-noise ratio depends on the receiver filter, transmitted signal envelope, and receiver noise spectral density. Maximization of this signal-to-noise ratio when range resolution constraints are imposed is discussed, and a receiver design approach specifically adapted for Doppler weather radars is developed. 相似文献
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Radar ECCM techniques are well known. Heretofore the listed ECCM effects have generally been to counteract the effects of ECM. This approach is one of attempting to cure an illness, rather than preventing it. Modem ECM systems usually include an ESM receiver to detect the radar signal, identify it by its emission characteristics, assess its importance, select the proper ECM, and signal to initiate ECM. If the ESM receiver detection of the radar signal can be delayed/denied, or the identification be confused, either the wrong ECM may be applied, or delayed. The radar may thus not be confronted with timely, proper ECM. Radar operation may therefore be possible. This paper introduces and defines CESM, a new category of radar ECCM. There are two principles of CESM-those which delay/deny ESM receiver detection, and those which confuse/impede signal identification. Illustrative examples of CESM techniques/operating techniques are given. It is shown that many CESM techniques may have multiple roles by impeding detection, impeding identification, and also diluting effects of ECM 相似文献
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针对有源对消隐身要求的系统延时短、反应速度快、信号参数测量和对消波幅相控制精度高的特点,设计了一个基于相控阵技术、数字射频存储器(DRFM)和现场可编程门阵列(FPGA)的有源对消系统。为了解决目标雷达散射截面计算量太大、不能有流水线延迟和难以实现实时计算等问题,采用离线计算的方法,预先建立目标的全向雷达散射截面(RCS)数据库、杂波数据库和噪声数据库,由FPGA根据测得的雷达信号参数在数据库中查找到相应的目标回波数据,实时调整对消波的幅度和相位,使对方的雷达接收机始终处于合成方向图的零点。最后通过仿真计算验证了该设计方案的有效性。 相似文献
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Radar target probing and measurement are challenging tasks for Radio Frequency Simulation (RFS) with pulse radar signal. Due to the long-time duration of pulse radar signal and the limited space of anechoic chamber, the reflected signal returns before pulse radar signal is fully transmitted in RFS. As a consequence, the transmitted and reflected signals are coupled at the receiver. To handle this problem, the Interrupted Transmitting and Receiving (ITR) experiment system is constructed in this paper by dividing the pulse radar signal into sub-pulses. The target echo can be obtained by transmitting and receiving the sub-pulses intermittently. Furthermore, the principles of ITR are discussed and the target probing experiments are performed with the ITR system. It is demonstrated that the ITR system can overcome the coupling between the reflected and transmitted signals. Based on the target probing results, the performance of pulse radar target probing and measurement can be verified in RFS with the ITR system. 相似文献