MAPTEK I-Site 8200ER三维激光扫描仪测角精度研究

采用MAPTEK I-Site 8200ER三维激光扫描仪与拓普康GPT-3002LNC全站仪为实验设备,在同种距离条件下,分别获取扫描数据和全站仪观测数据,将全站仪的观测角度值作为基准,MAPTEK I-Site 8200ER三维激光扫描仪观测的数据反算的角度作为观测值,建立平差模型,通过最小二乘法解算扫描仪的水平角和垂直角精度。研究结果表明,MAPTEK I-Site 8200ER三维激光扫描仪测角精度符合标称测角精度。     

田间作业机组激光导引系统设计与试验

为提高机组田间作业行驶的直线性,利用激光方向性好、发散角小、分辨率好、不受电磁干扰、无累积误差等特点,设计了一种激光导引机组作业系统,该系统主要由激光发射装置、调平装置、激光接收装置等部分组成。系统工作时,由激光发射器发出的红光激光,被安装在拖拉机上的激光接收装置接收,通过解调转换为电信号,由LED灯指示出机组的方向偏移,从而辅助驾驶员调整拖拉机方向,进行直线行驶。详细阐述了系统的结构和原理,以及关键部分的设计。初步试验表明,200 m范围内,激光导引系统导向精度,受外界光照影响小,机组偏移距离在3.18 cm左右,相比划行器,提高了作业精度。     

喷油雾锥闪光测相装置的研究

喷油雾锥闪光测相装置是一种能够保证喷油系统修理质量,易于在喷油泵试验台上改装的性能指标检测装置.本文论述了该装置的工作原理和组成,着重对其工作精度进行了分析研究.结果表明:正确使用该装置、能保证检测误差不大于1%.为此,给出了确保装置工作精度的使用规则.     

中点多边形的简易平差法

中点多边形的简易平差法、同“最小二乘法平差”及“近似平差”比较、方法简便、工作量小、确保精度、易于推广。在独立地区进行小面积测图时、可以采用。该平差法的基本原则,对于测图控制的单三角锁和线型锁也同样适用。     

罗盘导线定位及其精度分析

为解决森林调查中罗盘定位的精度问题,利用全站仪具有测量边长和角度精度高的特点,将其测量值作为真值.用罗盘仪对其值进行重复观测,进行比较研究,通过间接平差,得出罗盘仪测量边长和竖角的精度,由此推导出罗盘导线和罗盘测树高的精度.试验表明,1 km罗盘支导线最弱点的中误差达3 m,罗盘测树高的相对精度达5%.这个精度能够满足林业上的测量要求.由此可见,用罗盘进行辅助定位,是一种理想手段.     

一种全站仪精准量测立木直径的方法

立木直径是森林资源调查的重要参数。本文提出了一种基于免棱镜全站仪对边测量原理的立木树干直径精 准量测方法,并以南方全站仪NTS-3401 为例,对该方法的理论精度进行了论证,结合量测数据对实际精度进行了 分析。结果表明:免棱镜全站仪对边测量原理的立木树干直径精准量测方法的理论精度中误差在0.4 mm 以内;使 用胸径尺量测立木直径3 次取平均值作为真值,用来检验全站仪量测立木树干直径的精度,数据表明真误差控制 在1 mm 以内,而林业测量中要求测量结果精确至1 mm。本文提出的全站仪精准量测立木直径的方法达到了林业 测量中量测立木直径毫米级的精度要求,可以解决非接触式量测立木上部(2 m 以上)直径的难题。      

膨胀烟梗体积测量系统的设计研究及验证

【目的】为提升膨胀烟梗体积的测量精度及稳定性,基于等温过程中的气体状态方程设计了一套膨胀烟梗体积测量系统,该系统主要由校准装置和体积测定装置两部分组成,通过砝码重量产生的压强以及研究对象气体的体积变化对烟梗体积进行表征。【方法】以膨胀烟梗和回潮后的膨胀烟梗为试验材料,利用线性回归分析的方法建立砝码重量与待测物体积之间的关系模型,并通过试验分别对系统的测量精度和稳定性进行验证。【结果】①砝码重量x与■(记■,A为定值且等于2.955×10~(-3),Vx为待测物体积)成线性关系,且所建线性回归模型为Y=171.750x-1116.991。②该装置对膨胀烟梗和回潮后膨胀烟梗进行体积测定的平均相对误差分别为2.631%和3.618%,重复性检测最大变异系数分别为0.662%和0.542%,可满足装置检测精度需求,且装置重复性较好。【结论】该装置为烟草行业膨胀烟梗体积测定提供了一种精确有效的方法。     

土地资源详查中面积量测精度与线状地物扣除的探讨

本文从误差理论的角度,探讨了面积量测过程中,控制面积的精度与分区数目n之关系为:m_(?)=m(n~1/2),从而得出了通过控制分区数目n,来达到提高面积量测精度之目的。同时设计了线状地物两边扣除的辅助用表,以使面积汇总工作的顺利进行。     

农机触土部件前行阻力测试装置的设计与试验

田间作业机械的工作阻力分析是农业机械设计工作中一重要环节,对试验装置的可靠性和测量精度具有较高要求。为研究农机关键触土部件的试验样件的前行阻力,本文设计了一种阻力测试装置,并保证了较高的稳定性和测量精度。针对该装置在正常工作时产生的振动是否会影响其工作性能,利用Solid Works软件对测试装置的台架进行三维建模,并采用有限元分析软件ANSYS-Workbench对其进行模态分析,求解出台架的前6阶模态频率与振型。模态分析结果表明:台架的前6阶固有频率分布在21~38Hz之间,而当牵引台的行进速度为0.1~1.0m·s-1时,该装置受到的外激频率为0.346~3.462Hz,远低于台架的低阶固有频率21.778Hz,有效地避免了共振的产生。以插秧机船板样件的拖拽试验为例,通过三因素三水平正交试验,分析该装置结构设计的合理性。分析结果表明:船板样式、配重和前进速度对试验指标的影响极显著,并得出各因素的最优组合,即前进速度为0.4m·s-1、配重为0.7kg、仿生船板样件的滑行阻力最小。该研究为水田、旱地作业机械关键触土部件的试验样件的前行阻力分析提供了条件。     

激光平地机械化技术

激光机械控制平地机械化技术是目前世界上最先进的土地平整技术，由美国AGL公司率先开发研制成功。激光机械控制平地系统是利用激光辐射在田面上方形成的平面作为土地平整的控制标准，用液压控制系统自动地、灵敏地、快速地、精确地控制平地铲的升降，实施土地的精平作业。激光机械控制平地作业一般情况下应在采用常规机械平地设备完成对田面粗平后，再使用该“系统”进行田面的“精平”作业，实现高精度的土地平整。     

Real-Time Estimation of Citrus Canopy Volume Based on Laser Scanner and Irregular Triangular Prism Module Method

【Objective】Accurate measurement of volume and structure of fruit tree canopy can provide important reference for variable application of pesticide and fertilizer, as well as yield estimation. In order to accurately measure the canopy volume, a scanning platform based on laser sensor (LMS111-10100, SICK) was built. Aiming at the problem of irregular canopy shape, the poor accuracy of the existing real-time measurement methods of canopy volume and difficult to measure and estimate the canopy volume, a new estimation method based on irregular triangular prism modules was proposed in this work. 【Method】Five spherical landscape trees with regular canopy and ten citrus trees with irregular canopy were scanned by the laser sensor at the speeds of 0.5, 1.0 and 1.5 m·s ^-1, respectively. The canopy volume was measured by two methods: cuboid module method (CMM) and irregular triangular prism module method (ITPMM), and the error analysis was conducted based on manual measurement. 【Result】 The results showed that the error ranges of CMM for measuring landscape trees at the different speeds of 0.5, 1.0 and 1.5 m·s ^-1were 4.17%-6.59%, 4.56%-7.42% and 4.17%-9.86%, respectively, while the error ranges of the ITPMM for measuring landscape trees were 2.37%-4.63%, 3.18%-5.00% and 4.10%-5.73%, respectively. The distance range of the relative error of the two methods for measuring citrus trees was -0.28%-4.22%%, and the average difference was 1.78%. The error ranges of CMM for measuring citrus trees at the different speeds of 0.5, 1.0 and 1.5 m·s ^-1 were 11.63%-31.02%, 11.88%-33.23% and 13.28%-33.30%, respectively. The error ranges by ITPMM for measuring citrus trees were 3.25%-6.69%, 4.50%-8.31% and 5.66%-11.55%, respectively. The distance range of the relative error of the two methods for measuring citrus trees was 6.43%-26.20%, and the average difference was 13.04%. 【Conclusion】 The research showed that the estimation error of the ITPMM was significantly smaller than the CMM. For the same target, when the speed was 0.5 m·s ^-1, both of the estimation accuracy for the two methods were the highest. As the sensor speed increased, laser scanning points on the canopy decreased. So, the relative error of volume estimation increased with increase of advance speed of the laser sensor. When scanning the regular target, the accuracy difference between the two methods was small; when scanning the irregular target, the error of the CMM was larger. The processing time of a frame laser data by the CMM was 2.86 ms, and the processing time by the ITPMM was 4.73 ms, which were less than the scanning period of 20 ms of the laser sensor. The data processing time could match the acquirement of real-time collection and processing of laser data.     

The Lunar Laser Ranging Experiment: Accurate ranges have given a large improvement in the lunar orbit and new selenophysical information

The lunar ranging measurements now being made at the McDonald Observatory have an accuracy of 1 nsec in round-trip travel time. This corresponds to 15 cm in the one-way distance. The use of lasers with pulse-lengths of less than 1 nsec is expected to give an accuracy of 2 to 3 cm in the next few years. A new station is under construction in Hawaii, and additional stations in other countries are either in operation or under development. It is hoped that these stations will form the basis for a worldwide network to determine polar motion and earth rotation on a regular basis, and will assist in providing information about movement of the tectonic plates making up the earth's surface. Several mobile lunar ranging stations with telescopes having diameters of 1.0 m or less could, in the future, greatly extend the information obtainable about motions within and between the tectonic plates. The data obtained so far by the McDonald Observatory have been used to generate a new lunar ephemeris based on direct numerical integration of the equations of motion for the moon and planets. With this ephemeris, the range to the three Apollo retro-reflectors can be fit to an accuracy of 5 m by adjusting the differences in moments of inertia of the moon about its principal axes, the selenocentric coordinates of the reflectors, and the McDonald longitude. The accuracy of fitting the results is limited currently by errors of the order of an arc second in the angular orientation of the moon, as derived from the best available theory of how the moon rotates in response to the torques acting on it. Both a new calculation of the moon's orientation as a function of time based on direct numerical integration of the torque equations and a new analytic theory of the moon's orientation are expected to be available soon, and to improve considerably the accuracy of fitting the data. The accuracy already achieved routinely in lunar laser ranging represents a hundredfold improvement over any previously available knowledge of the distance to points on the lunar surface. Already, extremely complex structure has been observed in the lunar rotation and significant improvement has been achieved in our knowledge of lunar orbit. The selenocentric coordinates of the retroreflectors give improved reference points for use in lunar mapping, and new information on the lunar mass distribution has been obtained. Beyond the applications discussed in this article, however, the history of science shows many cases of previously unknown, phenomena discovered as a consequence of major improvements in the accuracy of measurements. It will be interesting to see whether this once again proves the case as we acquire an extended series of lunar distance observations with decimetric and then centimetric accuracy.     

几种测量方法在森林资源调查中的应用与精度分析

通过外业调查数据分析和理论推导,对林业调查中的几种测量方法进行了比较分析。研究表明：①罗盘仪由于制作粗糙,在标准样地测设中尚能满足规范要求,但随着距离和竖直角的增加,精度急剧下降,在大范围的林地面积和科研特殊需要的测量中操作不便捷,精度差,效率低;②全站仪测设样地边长不超过100 m时,半测回的距离测量可达到1/10 000,高差测量误差不超过1 cm,且受距离和竖直角的影响较小;③当面积大于3.34 hm^2,边长超过100 m时,手持全球定位系统（GPS）完全可代替罗盘仪,并可通过坐标差分或修正坐标转换参数来提高测量精度。另外,网络RTK的发展必将连同全站仪成为精准林业测量的主要仪器设备。     

基于超声波测距的激光角度初始化系统研究

为实现双激光源定位系统中激光发射角的自动测量,建立了基于超声波测距的激光角度初始化系统。系统采用主站和从站的工作方式,利用三角定位原理,通过激光牵引超声波测量基线和双边距离,根据角度解算程序,完成系统初始化角度的自动测量。同时,通过加入延时补偿、温度补偿及高度补偿等相关算法,使得在20 m的测量范围内,超声波测距的误差不超过2 cm,激光角度初始化误差小于0.05°。     

激光预打孔接装纸透气度与孔面积数学模型的建立

研究建立卷烟激光预打孔接装纸透气度和打孔孔径关系。设置不同打孔排数、孔数的激光预打孔接装纸,分别测试其透气度和孔面积,分析透气度和孔面积的关联性,建立数学模型。结果表明,激光预打孔接装纸透气度和孔面积高度相关,单位长度孔面积(S,μm2/cm)和透气度(A,cm3/min,150A≤800)的较优回归方程为S=547.3A+37 813.6(r=0.985,P0.000 1),利用所建数学模型计算打孔孔径,与实测值的偏差均小于1%。     

多边形草沙障防风效果研究

为了解正三角形、正方形和正六边形格状草沙障的防风固沙能力,通过测定沙障样地内不同高度风速,针对单个网格面积为1 m2的3种沙障,对沙障的防风效能、风速廓线特征和地表粗糙度进行研究。结果表明,正三角形和正六边形沙障的防风效能显著大于正方形沙障。高度为0.2 m时,正方形沙障的防风效能比三角形和六边形沙障分别低12%和8%,高度为0.3 m时,分别低11%和10%。0.2~0.3 m高度范围内,三角形沙障和六边形沙障的防风效能差异不显著。风速小于6 m/s时,地表粗糙度随风速变化接近线性变化规律。裸露地表 1 m高处,风速为4 m/s时,裸露地表粗糙度为0.166 cm,三角形沙障、正方形沙障和六边形沙障的地表粗糙度分别为11.5、9.3和10.4 cm,分别为裸露地表粗糙度的69.3、56和62.7倍。三角形沙障的地表粗糙度比正方形沙障和六边形沙障的地表粗糙度分别高23.7%和10.5%。铺设三角形沙障的地表粗糙度最大。      

输营养液对天目山柳杉的影响

为了防止柳杉瘿瘤病的蔓延对天目山柳杉Cryptomeriafortunei健康的影响,采取了多种防治措施,其中之一就是输营养液。通过对柳杉新梢生长量、相对叶绿素含量、叶绿素荧光参数的测定以及对柳杉瘿瘤分布格局的调查,研究了输营养液对天目山柳杉的影响。结果表明：在3月到10月期间,输营养液柳杉的新梢相对生长量比对照的大5．7％;在8月输营养液柳杉的相对叶绿素含量值比对照的大3．7％,10月两者均迅速降低;8月输过营养液柳杉的光系统Ⅱ光量子效率（Fv／Fm）值是对照柳杉的1．29倍;目前试验柳杉枝的瘿瘤以直径1～3cm的中瘿瘤最多,直径〈1cm和直径〉6cm的瘿瘤分布很少。输营养液在一定程度能改善天目山柳杉健康状况。     

新型生物可降解PLA沙障与传统草方格沙障防风效益

为了解新型材料生物可降解聚乳酸纤维(PLA)沙障防风效益,通过测定PLA沙障样地内不同高度风速,分别研究1 m×1 m、2 m×2 m、3 m×3 m规格PLA沙障防风效能、地表粗糙度与风速廓线特征,同时以相同坡位同种规格的传统半隐蔽式麦草沙障样地和流动沙丘为对照,对比研究了PLA沙障与传统麦草沙障的防风效益。结果表明,新型生物可降解PLA沙障防风效能显著大于麦草沙障,2种类型沙障最大差值可达10.3%,2种材料沙障不同规格防护效果为1 m×1 m规格较其他2种规格更好;2种材料沙障增加地表粗糙度表现为PLA沙障麦草沙障流动沙丘,且均随规格增大呈逐渐下降趋势,在相同地形条件下,PLA沙障地表粗糙度均值为麦草沙障的1.4倍;2种材料沙障在迎风坡坡底、坡中、坡顶及背风坡4种地形下地表粗糙度差异不明显,其地表粗糙度均值为0.7 cm;1 m×1 m规格的PLA方格沙障和麦草沙障内的风速廓线曲线呈现“S”型曲线特征,而在2 m×2 m和3 m×3 m规格的2种材料沙障内,风速廓线与对照裸沙丘相似,其风速廓线均呈指数函数分布。随着沙障规格的增大,降低风速作用减弱,其风速廓线逐渐由“S”型趋向于指数函数曲线。      

基于TCD2252D的线径测量仪研究

分析了基于线阵图像传感器的线径测量仪的基本原理、硬件构成和软件设计。系统通过使用二值化电路对CCD视频信号进行处理,通过单片机对被遮挡像元计数在数码管上显示测量结果。试验结果表明,该测径仪结构简单,测量精度高。     

基于多旋翼大疆无人机的土地利用正射遥感影像的快速获取方法研究

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