科创中国

把雷达角度跟踪伺服系统近似为一种线性时滞系统,雷达角度跟踪系统结构由考虑时滞的电流环、速度环及位置环构成,在高斯噪声输入时,采用状态空间法仿真出角度误差,推导出干扰下武器系统的脱靶量、一次射击杀伤概率的计算模型,从而研究高斯噪声干扰下时滞雷达角跟踪伺服系统的效能评估.仿真表明:高斯噪声干扰时位置环发生跳跃、速度环不收敛、电流环产生振荡;时滞小时高斯噪声下角度误差变化大,由此导致脱靶量增大,杀伤概率下降,因此干扰有效.

By recording nocturnally migrating passerines with tracking radar we have investigated how coastlines affect the migrants' flight paths. Birds could use coastlines as an orientation aid or as a reference cue to compensate for wind drift while mi- grating. However, on the small scale of Falsterbo Peninsula in southern Sweden, we found very little effect of coastlines on migrants flight paths, irrespective of altitude. We tracked 2 930 migrants in three autumn and two spring seasons, at altitudes from 60 up to 3 000 meters. We compared tracks of migrants flying in three different areas, which correspond to the three main coastlines, and can demonstrate that the orientation of the tracks did not differ in a way consistent with the coastlines between the areas in autumn, and showed only a slight effect in spring. This is in accordance with earlier infrared device monitoring in Falsterbo, but contrary to earlier visual observations. It supports the view of nocturnally migrating passerines as mainly broad-front migrants. Even though the coastlines on the scale of the peninsula affected the flight paths very little, it is possible that the coastline has an effect on a larger regional scale, by migrants avoiding long sea crossings and thereby being funneled towards the peninsula, but this remains to be investigated [Current Zoology 60 (5): 660-669, 2014].

单台雷达的定位精度低,致使多台雷达的融合定位精度较低.在多台雷达实时跟踪目标过程中,雷达的测角误差随距离的增加而增大,而测距误差变化较小.为了提高远距离目标的跟踪定位精度,本文提出了组网雷达的交会定位方法.利用至少3台雷达的测距信息,依据雷达与目标的空间几何关系,推导出该方法的数学模型,分析了定位精度的影响因素.利用组网雷达的实际测量数据进行试验,仿真结果表明,距离目标较近时交会法与融合法的定位精度相当,距离目标较远时交会法优于融合法.

In order to compare the two species' flight performance over the exposed and windy Falsterbo Peninsula, where thermal conditions seldomly are very favorable, we used tracking radar to study flight parameters of sparrowhawks Accipiter ni- sus and common buzzards Buteo buteo during autumn migration. The results showed a clear difference between sparrowhawks and common buzzards in their flight altitudes and speeds, and in the wind conditions they encountered. Common buzzards had higher flight altitudes and were more selective of wind. Flight altitude was negatively related to the wind speed, which was most pronounced for common buzzards. Sparrowhawks had higher mean air- and cross-country speeds than common buzzards. Air- speed was negatively related, whereas ground and cross-country speeds were positively related to the tailwind component for both raptors. The differences between sparrowhawks and buzzards could to a large degree be explained by a larger dependence on thermal soaring among the common buzzards; a strategy associated with selectivity for favourable thermal and wind conditions during migratory flight. An additional important explanation for the interspecific differences was the habit of the sparrowhawks to combine migratory flight with hunting for prey, which makes it prone to fly at lower altitudes and use flapping flight to a much larger degree than common buzzards which do not forage during their migratory passage of the Falsterbo Peninsula [Current Zoo- logy 60(5): 670-679, 2014].

有效掩护区是定量研究对星载SAR干扰效能比较简洁的手段.通过定义对星载SAR压制式干扰的有效掩护距离和有效掩护区,并结合雷达干扰统一方程,研究建立了对星载SAR干扰的仿真模型,并根据不同时期SAR所采取的天线,引入二种三维天线增益模型进行了仿真,可以得到不同输入条件下干扰掩护区,仿真结果验证了模型的合理性,有利于定量分析和评估对星载SAR的干扰效能.

随着舰载超视距武器系统的广泛应用,舰载火控雷达的效能对武器系统的影响越来越明显,大气是影响火控雷达作用距离的最主要原因之一,因此研究大气对舰载火控雷达效能的影响很有必要.该文从电磁衰减出发研究了大气对电磁波能量的影响;从电磁折射入手分析了大气对电磁波传播路径的影响.

C3I系统是实现指挥、控制、通信和情报的军事电子综合信息系统,雷达作为系统中的重要组成部分,对C3I系统作战效能的发挥有重要影响.针对雷达对目标探测生成的目标航迹问题,基于航迹质量随着目标距离增加而减小的假设,依据雷达性能确定航迹质量服从指数分布,首先提出了基于雷达烧穿距离的航迹质量评估模型;其次,根据历史航迹数据,依据马尔可夫线性估计理论枸建误差协方差估升矩阵,建立了航迹质量预测模型;由航迹质量是随着航迹误差减少而提高的原则以分段形式建立航迹误差与航迹质量的映鼽由映射表确定航迹质量值;最后通过Mallab进行仿真,保证了模型的有效性.

Migrating landbirds are known to follow coast lines and concentrate on peninsulas prior to crossing water bodies, es- pecially during daylight but also at night, creating enhanced potential collision hazards with man-made objects. Knowing where these avian migration "hot-spots" occur in time and space is vital to improve flight safety and inform the spatial planning process (e.g. environmental assessments for offshore windfarms). We developed a simple spatial model to identify avian migration hot- spots in coastal areas based on prevailing migration orientation and coastline features known, from visual and radar observations, to concentrate migrating landbirds around land masses. Regional scale model validation was achieved by combining nocturnal passerine movement data gathered from two tier radar coverage (long-range dual-polarization Doppler weather radar and short- range marine surveillance radar) and standardised bird ringing. Applied on a national scale, the model correctly identified the ten most important Danish coastal hot-spots for spring migrants and predicted the relative numbers of birds that concentrated at each site. These bird numbers corresponded well with historical observational data. Here, we provide a potential framework for the es- tablishment of the first three-dimensional avian airspace sanctuaries, which could contribute to more effective conservation of long-distance migratory birds [Current Zoology 60 (5): 680-691, 2014].

为了处理二阶系统模型参数的大范围不确定性,提出了基于跟踪微分器的模型参考自适应控制,利用两个非线性跟踪微分器分别得到系统输出的微分信号和误差的微分信号,同时抑制了高频噪声放大效应.根据被控对象的数学模型,自适应调节律能自动实时调节控制律中的参数.实验结果表明,当雷达伺服系统被控对象模型的参数在较大范围内变化时,该新型控制器有效补偿了二阶系统参数的不确定性,提高了伺服系统稳态和动态跟踪精度,保证了系统的全局渐近稳定.

以配套于武器系统的光电跟踪系统为基础,论述了光电跟踪系统在论证与设计中应主要考虑的问题.从实际系统情况出发,讨论了光电跟踪系统的传感器选择原则和“T型”与“U型”架式配置优缺点.分析了确定作用距离、跟踪精度、响应速度、工作范围等核心指标的主要因数,确定了与核心指标相对应的光电跟踪系统内部的指标需相应考虑的因数,提出了导引截获、轴系关系等与系统关联的技术因数等.