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针对拖靶超低空掠海恒高飞行时精确测高问题,分析了无线电高度表测高模型和加速度计测高模型存在的缺陷,构造了由无线电高度表和加速度计组成Kalman互补滤波器,在给出算法的基础上,设计了互补测高系统.从理论和仿真两个方面对互补测高方案的有效性进行分析,结果表明互补测高方案可有效提高测高精度,具有较强的工程应用价值. 相似文献
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利用数据平滑抑制无线电高度表的多普勒效应误差 总被引:3,自引:0,他引:3
针对多普勒效应对频率测量造成的误差使无线电高度表的测高精度受到影响的问题,提出使用加权平均算法、N次平均算法来抑制多普勒效应误差对测量的影响,并对它们的优缺点进行了分析,给出了各自适用的场合。这些算法分别在国内的三种无线电高度表上使用的效果证明了它们的可行性和可靠性。 相似文献
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针对伪码测距高度表增大测高范围和提高测量精度矛盾的情况,给出了一种在提高伪码测距高度表的测高精度时不影响测高范围的方法,并利用现行电子元器件的精确和高速处理能力来实现;该方法引入频率为伪随机序列码元频率的M倍的脉冲序列,通过对其单个脉冲的增减,得到本地伪码与接收伪码在码片内的准确延时,从而提高高度的测量精度;仿真结果表明,使用FPGA实现此方法既能满足高度表提高测量精度的要求,同时也满足测高范围大的要求。 相似文献
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在宽带数字式信道化接收机中,对信道化后信号处理的方法通常有在数字式信道化处理后的每个信道后接相位比较器、单比特接收机、另一组FFT.文章对相位法测频进行了matlab仿真,提出了一种解模糊算法.仿真结果表明这种解模糊算法可以得到很好的结果.最后,对此测频方法存在的问题做了分析,并指出了要完善这种测频方法还需要做的下步工作. 相似文献
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在临近空间通信系统中,降雨、大气、闪烁等都会引起空地链路信道质量的恶化。通过分析Ka波段临近空间通信信道的电波传播特性,建立了Ka波段临近空间静止通信信道模型。分析了空地链路中仰角变化时,降雨对信号衰落的影响,估算了不同仰角下的相关参数值,并对不同仰角下Ka波段临近空间静止信道性能进行仿真,验证了模型的正确性,为临近空间链路分析及后续研究工作提供了平台。 相似文献
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王磊 《计算机光盘软件与应用》2014,(18):298+300
在对比分析常用的三种线性调频通信多址技术的基础上,对时间交叠多址技术的基本原理和其在AWGN信道下的误码性能进行了理论分析。通过MATLAB仿真实现了四种线性调频技术在采用时间交叠多址技术时的误码性能分析,分别给出了在高斯白噪声信道下,各种技术分别在用户数为一、四、六、八情况下的误比特图,并进行分析比较。 相似文献
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采用振动筒式压力传感器,结合单片机技术设计了一种高精度的数字式气压高度表,文中详细的论述了硬件设计,给出了软件设计流程,并从硬件上和软件两方面对引起测量压力的温度误差、静压误差和非线性误差进行了补偿,进一步提高了气压高度表的实际精度,该气压高度表与传统膜盒式气压高度表相比,具有精度高、结构简单、体积小和重量轻等优点。 相似文献
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星载雷达高度计是一种重要的对海洋进行精确测量的主动式微波遥感器。因为高度计能够有效地测量卫星到海面的高度、海面有效波高和海面后向散射系数,它在海洋大地水准面研究和海洋应用研究的诸多方面得到了广泛的应用。海面回波模拟器能够接收和处理高度计信号,产生海面回波波谱来调制高度计信号,最后精确延时后发射回高度计,是在地面对高度计进行测试和定标的一种有效手段。由于功能的全面性,回波模拟器是一个复杂度不亚于高度计本身的系统,因此,对回波模拟器的分析和仿真对于指导它的设计、确定它的精度以及定标的效果有着重要意义。介绍了回波模拟器的结构,分析了海面回波波谱的产生原理并设计了回波模拟器的SIMULINK仿真模型,给出并分析了仿真结果。 相似文献
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引信是通过测量弹头距地面的相对高度来控制战斗部在最佳高度起爆,以提高战斗部的杀伤威力。而近炸引信的目的则是在未到达预定引爆区域而又无法避免对方拦截的情况下,引爆战斗部,以避免战斗部被对方完全破坏后的失效。针对该应用,本文在毫米波波段设计并实现了一种基于调频连续波体制的近炸引信信号处理器。 相似文献
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Roll angle is an important parameter for three-dimensional imaging altimeter to measure Sea Surface Height.The height error due to the roll angle error grows linearly across the swath and a slight error of roll angle will results in a large height error within observation range.So a very accurate knowledge of the roll angle error is required.Nadir interferometric phase has a strong correlation with the roll angle,so using the nadir interferometric phase from the interference image can get roll angle more accurately than instrument measurements.It’s possible to meet the centimeter-level accuracy after correcting the roll angle error.Simulation measurement and elevation reconstruction based on the geometric relationship were performed,and the research of correction the roll angle error by nadir interferometric phase was carried out.Both theoretical calculation and numerical simulation show that the measurement accuracy of roll angle can be as high as 0.03 arcsecond when the accuracy of nadir interferometric phase is 10-3rad.In this case,the height measurement accuracy have been averaged across a swath between 10 and 60 km of nadir will decrease to 0.48 cm which is 6.02 cm when the roll accuracy is 0.36 arcsecond.It means that the nadir interferometric phase method can effectively correct the roll error of three-dimensional imaging altimeter. 相似文献
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Yongcun Cheng Qing Xu Hui Lin Peng Xiu Xiaobin Yin 《International journal of remote sensing》2013,34(19):5699-5716
Based on the specular reflection theory of electromagnetic waves at rough sea surface and the wind wave spectrum model with a wave age factor, the sea surface wind speeds are retrieved from the normalized radar backscatter cross‐section (NRCS) measured by TOPEX/Poseidon (T/P) Ku‐band altimeter using the mean square slope (MSS) calculated from the spectrum models of the wind waves and the gravity‐capillary waves. A relationship between wave age and non‐dimensional wave height is applied to compute the wave age factor using the significant wave height (SWH) and wind speeds obtained from buoy or altimeter simultaneously. The study indicates that the wave age factor has a significant impact on the retrieval of altimeter wind speed. Compared with the operational algorithm for retrieving altimeter wind speed, the wind speed retrieved from the new analytical algorithm based on the wind wave spectrum model with the wave age factor, proposed in this study, can match the buoy measurements better. The effects of the wave age factor on altimeter wind speed retrieval are also shown quantitatively through a series of experiments and measurements. The comparison with the operational algorithm indicates that both the bias and root mean square error (RMSE) between wind speeds retrieved by the proposed analytical algorithm and those observed by the buoy decrease significantly. In the Gulf of Mexico, with the new analytical algorithm, more accurate altimeter wind speeds are retrieved. 相似文献
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An airborne laser profiling altimeter was used to measure surface features and properties of the landscape during the HAPEX-Sahel Experiment in Niger, Africa in September 1992. The laser altimeter makes 4000 measurements per second with a vertical resolution of 5 cm. Airborne laser and detailed field measurements of vegetation heights had similar average heights and frequency distribution. Laser transects were used to estimate land surface topography, gully and channel morphology, and vegetation properties ( height, cover and distribution). Land surface changes related to soil erosion and channel development were measured. For 1 km laser transects over tiger bush communities, the maximum vegetation height was between 4-5 and 6-5 m, with an average height of 21 m. Distances between the centre of rows of tiger bush vegetation averaged 100 m. For two laser transects, ground cover for tiger bush was estimated to be 225 and 301 per cent for vegetation greater than 0-5m tall and 190 and 25-8 per cent for vegetation greater than 10m tall. These values are similar to published values for tiger bush. Vegetation cover for 14 and 18 km transects was estimated to be 4 per cent for vegetation greater than 0-5 m tall. These cover values agree within 1-2 per cent with published data for short transects (? 100 m) for the area. The laser altimeter provided quick and accurate measurements for evaluating changes in land surface features. Such information provides a basis for understanding land degradation and a basis for management plans to rehabilitate the landscape. 相似文献
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针对空投翼伞雀降时的准确测高问题,在分析了现有高度测量设备优缺点的基础上,提出了采用声波高度计来提高高度测量信号的准确度。首先完成了声波高度计系统原理样机的研制,并利用设计的声波高度计系统在室内和室外针对不同反射面分别进行了不同高度情况下的试验研究,多组试验数据事后处理的最大测量误差均值分别为室内的0.326m和室外的0.814m,表明设计的高度计在试验量测范围内,其测量精度可以满足空投的要求。 相似文献
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介绍某型拖靶使用的KGWXX型无线电高度表静态模拟测高试验方法,给出了试验数据,并对试验结果进行了理论分析。静态模拟测高试验结果表明:该高度表可在超低空状态下提供稳定的高度数据,可以作为某型拖靶系统的高度传感器;该高度表提供的高度数据存在着较大的阶梯误差,将影响拖靶系统的恒高精度。通过分析静态模拟测高试验结果,指出了该高度表提供的高度数据存在较大阶梯误差的原因及解决途径。 相似文献