这项研究得到了 jsp 资助的科研项目 (16H02580, 17H03885) 和鸟取大学干旱土地研究中心联合研究项目的财政支持。

本研究的主要目的是利用阵列探地雷达系统来可视化地下水的动态过程, 如水的渗入, 也必须描述如何进行渗透试验。
1. 野外入渗试验
<ol><li>选择具有裸表面的用于渗透测试的站点。 注意:本研究对日本鸟取大学干旱土地研究中心的大型温室设施进行了渗透试验。有关详细信息16, 请参见最近的发布。</li>
	<li>在表面六2.5 米长的多孔管平行的位置在彼此之间的距离, 以确保均匀渗透 (图 2)。</li>
	<li>将管的一端连接到阀门调节的入口, 连接到蓄水池或水龙头, 另一端到出水口以除去多余的水。</li>
	<li>放置一个薄 910 x 1802 毫米2木面板 (略高于天线阵列), 以覆盖多孔管。</li>
	<li>在入渗试验前, 检查木面板对雷达信号的影响。</li>
	<li>在木面板旁边安装土壤湿度传感器, 以监测不同深度土壤含水量的变化。 注意:这些传感器的目的是提供参考数据, 用于交叉检查从雷达数据分析中得到的结果。在这项研究中, 在天线旁边安装了一个棒型土壤水分传感器 (参见材料表), 以监测土壤介电常数在10、20、30、40、60和100厘米深。</li>
</ol>2. 探地雷达测量
<ol><li>将阵列探地雷达天线放在木面板上。 注意:在这项研究中, 天线是静止的, 以确保记录信号的一致性。</li>
	<li>使用同轴电缆将天线连接到控制器。</li>
	<li>将控制器连接到带有以太网电缆的笔记本电脑上。</li>
	<li>确定天线组合及其序列, 以确保共同的偏移收集 (齿轮) 和多偏移收集 (MOG) 无缝收集。 注意:在这项研究中, 所有可能的组合, 为阵列雷达在我们的处置被使用 (110)。通过所有组合执行完整扫描需要少于1.5 秒。</li>
	<li>使用数据收集软件开始记录探地雷达数据。 注意:在向多孔管注入水之前, 开始采集数据是很重要的。</li>
	<li>打开阀门应用水 (即, 开始入渗过程)。 注意:在地基中注水速率可以从目标土的水力特性 (如水力电导率) 中确定。本研究使用的流速为7000厘米3/分钟, 低于沙丘砂的饱和水力电导率。</li>
	<li>在预先确定的水注入量后, 关闭阀门。 注意:连续注入4小时水, 试验中共用1680升水。</li>
	<li>继续与阵列雷达扫描一段时间, 以监测再分配过程, 进一步分析。 注意:在阀门关闭后, 阵列探地雷达一直在收集4小时的数据。然而, 这些数据并没有被分析为这里提出的研究。</li>
</ol>3. 速度估计的数据分析
<ol><li>通过从总体数据立方体中提取相对 Tx Rx 组合来重建齿轮和 CMP 数据。这是通过由作者开发的一些自定义代码完成的, 重新排列雷达剖面, 以便将 Tx-Rx 对与相同的偏移 (齿轮) 和具有相同中点 (CMP) 的两对组合在一起。 注意:由于 SFCW 探地雷达单元用于本研究, 原始数据处于频域;利用雷达系统制造商提供的软件, 对频率转换进行了操作。</li>
	<li>通过拟合计算的双向旅行时间、 tc、在所观测信号的渗透前反射的电磁波, 估计在给定的运行时间内润湿区域中的最佳 EM 波速。启发式确定了最佳曲线拟合速度。 <img alt="Equation 1" src="/files/ftp_upload/56847/56847eq1.jpg">(1) 其中d0是反射点的深度, x是 Tx 和 Rx 之间的距离, vr 是反射平面的根均方速度, t0是零偏移的双向旅行时间由 CMP radargram 确定。 注意:使用 MOG 的最常用速度估计方法是外表分析5,15,17。在表象分析中, 利用速度谱选取根平均平方速度。由于阵列探地雷达数据中观测到的低信噪比不允许我们开发出可靠的速度谱, 所以在本研究中不采用表象分析法进行速度估计。在其他正在进行的研究中, 寻找一种适当的过滤方法来生成可靠的速度谱。在本研究的范围内, 采用曲线拟合方法将 Eq (1) 与 CMP radargrams 相适应。</li>
	<li>使用 Eq (1), 使用估计 EM 速度vr, 在给定的运行时间内计算润湿前深度d0 。 注意:对于数据分析的这一部分, 齿轮数据集使用在等于113毫米的偏移量x上。</li>
</ol>

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本研究利用阵列探地雷达 (鸟取) 在日本沙沙丘附近的一个实验场进行渗透实验, 对湿润锋的深度进行跟踪。本研究采用的阵列探地雷达系统由10发射天线 (Tx) 和11接收天线 (Rx) 组成。系统可以配置为使用多达110种不同的 Tx Rx 组合。在渗透实验中, 所有110种组合都连续扫描1.5 秒, 使阵列固定在水被放置在表面的一些多孔管的位置。从时间推移数据立方体中重建了共偏移集 (齿轮) 和常用中点数据 (CMP)。与传统的双基地探地雷达系统相同的速率采集 CMP 数据几乎是不可能的。在实验中, 将天线留在静止记录中是非常重要的, 以获得重现性和有意义的时间推移数据。
虽然阵列探地雷达数据已被用于估计电磁波速度15, 但仅有少数研究分析了时间推移阵列探地雷达数据, 以估计水渗入等瞬态过程的 em 波速。本研究从时间失效的 CMP 数据中估计出电磁 (EM) 波速结构。将双向行程时间的双曲线曲线与 CMP radargrams 中的反射信号启发式, 以估计湿润区内的平均 EM 波速, 而不是进行表象分析, 因为低信噪比 (S/N) 数据的比率。当 s-/N 比值较低时, 表面分析不能用于生成可靠的速度谱。为了使用表象分析方法, 需要开发一种合适的滤波方法。在探地雷达天线旁安装有杆式土壤水分传感器, 测量土壤含水量在渗透试验过程中的变化;传感器被偏移在深度 10, 20, 30, 40 和 60 cm 并且独立地工作了。
利用估计的 EM 波速, 在渗透过程的1分钟间隔内计算润湿锋的深度。估计润湿锋的时间演化与土壤湿度传感器在20厘米以下深度的观测结果吻合较好。在较浅的深度, 对湿润前沿深度的探地雷达估计与土壤水分传感器的读数有差异。
总体上, 本研究表明, 阵列探地雷达系统能够通过收集时间推移共同中点 (CMP) 数据, 跟踪水渗入土壤中湿润前沿深度的演变过程。由于这种类型的数据不容易收集从传统的表面探地雷达之前, 这项研究获得的数据是第一个, 实际显示如何在一段时间内, 润湿前沿演变。今后的工作将探讨利用数据反演方法估算土壤水力参数的可能性。

了解渗流带的质量和能量传输过程对于许多农业和环境学科的应用都是很重要的。在这些过程中, 可变饱和水流是必不可少的过程, 因为许多其他的过程, 如物理, 地球化学, 生物, 甚至机械过程, 通常与水流相结合。地球物理技术的最新发展使人们得以监测非侵入渗流区的水文过程。在许多地球物理技术中, 探地雷达是最广泛使用的监测和描述土壤水动力学的技术之一, 因为雷达天线发射和接收的电磁波的传播是特征是土壤含水量1,2,3,4。在现有的系统中, 地面表面的探地雷达 (在手稿的其余部分被称为表面探地雷达) 是最常见的在一个领域使用。传统的表面探地雷达系统与一个发射机和一个接收器 (双基地雷达系统) 通常用于扫描地下与恒定的发射机-接收器分离 (偏移)。在此配置中收集的数据集也称为普通偏移收集 (齿轮)。雷达数据以时间序列的方式显示在发射机、最终反射器和回接收机之间的总行程时间上。为了将行程时间转换为深度信息, 需要对地下电磁波的波速进行估计。例如, 可以通过分析多偏移收集 (MOG) 数据集5来完成此操作。
虽然已有多项研究使用探地雷达监测地下渗透过程6,7,8,9, 他们都没有直接确定润湿锋或 EM 波的位置在渗透过程中随时间变化的速度结构。一般的方法是使用被埋在已知深度的物体作为参考反射器, 以确定平均电磁波速度和润湿锋深度。由于润湿锋在浸润过程中动态变化, 必须在短时间内收集时间推移 MOG, 以利用电磁波速度结构的变化而不使用参考对象。利用共同的双基地表面探地雷达天线, 在短间隔时间内收集 MOG 是困难或不可能的, 因为它需要手动移动天线来设置各种偏移配置。最近, 一家天线阵雷达 (简称阵列探地雷达) 已广泛应用于图像的地下快速和准确的10。阵列探地雷达的基本概念是通过电子方式切换安装在单个帧中的多个天线来提供密集的大片。阵列探地雷达系统主要用于快速生成3D 的大面积地下图像。这些系统典型应用的一些例子是公路和桥梁检查11, 考古学展望12和未爆炸弹药和地雷检测13,14。为此目的, 阵列探地雷达主要用于用恒定的天线分离结构扫描地下, 以收集齿轮。虽然已经证明, 用阵列雷达收集的 MOG 可以用于速度估计15, 但这种方法的实际应用仅限于少数情况。通过将天线阵列放置在固定位置, 可以很容易地收集到时间失效的 MOG。正如我们最近发布的16所演示的那样, 用阵列探地雷达系统收集的时间推移 radargrams 在垂直渗透实验中逐渐向下移动时, 很清楚地描绘了润湿前沿的反射信号。在沙丘上进行的。本文的主要目的是演示如何在渗透试验中利用阵列探地雷达收集时间推移 MOG, 以及如何分析这些数据来跟踪润湿前沿的深度。
在本研究中, 我们使用的天线阵列由10发射 (Tx0 Tx9) 和11接收 (Rx0-Rx10) 弓系单极天线组成。数组中天线元素的位移显示在图 1中 (请参见材料表)。天线阵列由一步频连续波形 (SFCW) 雷达单元控制, 其工作频率范围从 100 mhz 到3000兆赫。阵列雷达通过在天线阵列10中使用射频 (RF) 器在用户定义的 Rx-Tx 对序列中进行切换。此特定系统的 Tx Rx 组合的最大数目为110。在这个实验中, 我们配置了阵列探地雷达, 以使用所有110组合, 编程扫描序列, 使每个发射机, 从 Tx0 到 Tx9, 是连续配对的所有11接收机从 Rx0 到 Rx10。在所有110组合中执行扫描所需的时间少于1.5 秒。发射机和接收机之间的偏移量是根据天线元件的进给点之间的距离计算的, 其中垂直偏移量为85毫米, 如图 1所示。

<table><tbody><tr><td>GeoScope Radar Unit</td><td>3D Radar AS</td><td></td><td></td></tr><tr><td>DXG1820 antenna</td><td>3D Radar AS</td><td></td><td></td></tr><tr><td>PR2/6 Profile Probe&amp;nbsp;</td><td>Delta-T</td><td></td><td></td></tr></tbody></table>

tracking infiltration front depth using time-lapse multi-offset gathers collected with array antenna ground penetrating radar

在日本鸟取沙丘附近的一个试验场进行的渗透试验中, 利用地面耦合的密集天线阵列的地面穿透雷达系统收集数据。本研究使用的天线阵列由10发射天线 (Tx) 和11接收天线 (Rx) 组成。对于本实验, 系统配置为使用所有可能的 tx rx 配对, 从而产生了由110个 tx rx 组合组成的多偏移收集 (MOG)。该阵列在直接位于渗透区上方的位置处于静止状态, 每1.5 秒使用一个基于时间的触发器收集数据。在后处理过程中, 从 MOG 数据中重建了共偏移集 (齿轮) 和普通中点 (CMP) 数据立方体。很少有研究使用时间推移 CMP 数据来估计传播速度的变化。本文采用双曲线方程, 通过曲线拟合, 估计1分钟启发式的电磁 (EM) 波速。然后, 我们着手计算润湿锋的深度。随着时间的推移, 润湿锋的演变是与土壤水分传感器的观测相一致的, 它被置于20厘米以下的深度。研究结果表明, 这种阵列探地雷达系统能够准确、定量地监测地下动态过程, 如水渗流。

图 3显示了在将数据从频率转换为时间域之后, 在渗透实验的第一60分钟内每1.5 秒获得110个 Tx Rx 组合的时间推移面板图。为了提高反射深度, 采用带通滤波器进行增益补偿。面板图可以分为10节, 每个部分对应于一个特定的 Tx。Tx 的位置由一个白色三角形指示, 每个切片对应于记录为 Rx 的一个延时信号。垂直轴显示双向行程时间或行波管, 即电磁波从发射器到最终反射器和返回接收机所需的时间。配置文件在灰度色图中显示信号振幅。颜色的大对比表明记录的雷达信号有很高的振幅。电磁波反射是在不同介电常数的层间界面或与周围介质不同的电学特性的物体上产生的;高介电对比度将决定高振幅反射。在水的入渗过程中, 有一个区域称为过渡区, 水的含量逐渐从湿润区的边缘增加, 即水渗入到最初的干土中。在水表检测18的研究中观察到, 电磁波可能不在非常边缘, 而是在过渡区内反射。在手稿的其余部分, 这个反射区域被称为润湿锋。在图 3中, 在实验过程中, 随着时间的推移, 出现高振幅信号并稳步向下移动。这种反射确实是由润湿锋产生的, 因为水在地下逐渐向下渗透。从该图中可以重建齿轮和 CMP, 如图 2岩崎et . 所示。16
对每1分钟获得的 CMP 数据进行速度分析。对于每组 CMP 数据, 由 Eq 提供的双向旅行时间 (1) 是通过调整t0和vr(假定在湿区中的统一层) 来安装在润湿前端的反射。用0.3 米/ns 的速度拟合空气波, 纠正了时间零点。图 4以5分钟间隔从已用时间te = 5 分钟到te = 50 分钟显示 CMP 数据, 同时显示为白色线条的最佳曲线 (反射波的实线和空波的虚线)。由于空气波不是反射波, 而是发射机与接收机之间的直接信号, 所以行程时间随偏移量线性增加。所有的曲线都安装在反射波的正峰 (白颜色) 上。所有曲线都适合在所有偏移量的 CMP radargrams 中显示的观测到的反射曲线, 这意味着t0和vr 的估计值很好。对于渗透实验, 在天线和多孔管之间放置了一个干木面板。由于面板的介电常数比湿土低得多, 它对电磁波传播的影响可能是微不足道的, 即使它很薄。然后考虑了二层模型, 除了上述的统一层模型, 假设值为3的介电常数的前 5 cm。另外对于第二个模型, 在润湿锋产生的反射下, 用曲线拟合估计了 EM 波速vr 。
in 图 5中, 估计的润湿前深度被绘制为单层和双层模型的te 的函数。可以理解的是, 润湿前端在两种模型中的时间几乎呈线性向下移动, 除te = 10 分钟和te = 20 分钟之间的慢速之外. 两种模型之间的差异最初不是显著, 但随着时间的推移, 统一模型的估计比两层模型移动得略快。在图 5中, 使用菱形符号来标记来自湿度传感器的读数开始增加的时间, 以及它们后来变得稳定时的次数;这些与每个传感器深度的实线连接。如上所述, 电磁波的反射不一定发生在湿区的边缘;换句话说, 考虑到某种深度, 当传感器读数开始增加时, 不能期望这种反射与时间点相匹配。从这个意义上说, 反射是由于渗透前的深度水平, 达到了一定的水饱和度, 与下面的区域相比。考虑到30、40和60厘米深的传感器, 从探地雷达数据获得的润湿锋深度估计在时间线上的实线显示的范围内很好。探地雷达估计润湿锋到达20厘米深度的时间对应于传感器读数突然增加的时间, 而探地雷达估计达到10厘米的深度远快于湿度传感器所产生的速度。, 虽然在te = 5 分钟 (图 4) 之后, 已清楚地观察到润湿前端的反射信号。另外, 还必须指出, 探地雷达估计曲线的外推不经过原点。虽然不清楚是什么导致了这种差异在浅深度, 可能有几个可能的解释。它可以归因于土壤性质的异质性, 也可能是由于水的不均匀性的应用。如果确实如此, 在渗透过程中, 这种情况在较晚阶段会产生更大的影响。另一个解释可能是表面粗糙度影响时间零的确定。除了木面板和多孔管的作用外, 还应考虑表面粗糙度的影响。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56847/56847fig1.jpg"> 图 1: 本研究中使用的阵列探地雷达天线配置架构.V 形结构是领结单极天线。有10发射天线 (Tx) 和11接收天线 (Rx) 水平对齐。<a href="https://cloudflare.jove.com/files/ftp_upload/56847/56847fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56847/56847fig2.jpg"> 图 2:渗透实验的架构。(a) 顶部视图和 (B) 一个侧面视图, 其中阵列天线放置在六250厘米多孔管的顶部, 其排列为15厘米。<a href="https://cloudflare.jove.com/files/ftp_upload/56847/56847fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56847/56847fig3.jpg"> 图 3: 在渗透实验的前60分钟内获得的时间推移 radargram.数据包括110天线组合的记录信号。一个切片对应于用单个 Tx Rx 组合收集的时间推移数据。不同的颜色用于信号振幅。垂直黑线分隔每个 tx 的数据. 白色三角形表示 tx 的位置.<a href="https://cloudflare.jove.com/files/ftp_upload/56847/56847fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56847/56847fig4.jpg"> 图 4: Radargrams 的 CMP 在te = 5 分钟到te = 55 分钟5分钟的间隔.白色实线表示人工拟合的反射的双向旅行时间从润湿前面, 而白色虚线代表空气波浪的旅行时间。<a href="https://cloudflare.jove.com/files/ftp_upload/56847/56847fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/56847/56847fig5.jpg"> 图 5: 润湿前深度.从阵列探地雷达中估计的润湿前深度在时移多偏移量集合中, 作为统一 (三角形) 和双层 (正方形) 模型的经过时间的函数。两端有钻石的黑线显示了读数的初始增加和这些数据在每个传感器深度 (即过渡区域的持续时间) 达到稳定水平之间的时间。<a href="https://cloudflare.jove.com/files/ftp_upload/56847/56847fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>

Watch this Scientific Journal Video about Tracking Infiltration Front Depth Using Time-lapse Multi-offset Gathers Collected with Array Antenna Ground Penetrating Radar at JoVE.com

Tracking Infiltration Front Depth Using Time-lapse Multi-offset Gathers Collected with Array Antenna Ground Penetrating Radar

利用阵列天线探地雷达采集的时移多偏移收集跟踪入渗前深度

在这里, 我们提出了一个地面穿透雷达 (雷达) 系统基于地面耦合, 稠密的天线阵列监测地下水渗透的动态过程。渗透过程的时移雷达图像允许在渗透过程中估算润湿锋的深度。

A Ground Penetrating Radar (GPR) system based on a ground-coupled, densely populated antenna array was used to collect data during an infiltration ...

tracking-infiltration-front-depth-using-time-lapse-multi-offset

Research

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Unit 1

Horizontal and Vertical Curves

SCIENTISTS IN ACTION

7.7K 次观看.  Tokyo University of Agriculture and Technology. 在这里, 我们提出了一个地面穿透雷达 (雷达) 系统基于地面耦合, 稠密的天线阵列监测地下水渗透的动态过程。渗透过程的时移雷达图像允许在渗透过程中估算润湿锋的深度。

视频: Tracking Infiltration Front Depth Using Time-lapse Multi-offset Gathers Collected with Array Antenna Ground Penetrating Radar

Time Multiplexing Super Resolving Technique for Imaging from a Moving Platform

We propose a method for increasing the resolution of an object and overcoming the diffraction limit of an optical system installed on top of a moving imaging system, such as an airborne platform or satellite. The resolution improvement is obtained in a two-step process. First, three low resolution differently defocused images are being captured and the optical phase is retrieved using an improved iterative Gerchberg-Saxton based algorithm. The phase retrieval allows to numerically back propagate the field to the aperture plane. Second, the imaging system is shifted and the first step is repeated. The obtained optical fields at the aperture plane are combined and a synthetically increased lens aperture is generated along the direction of movement, yielding higher imaging resolution. The method resembles a well-known approach from the microwave regime called the Synthetic Aperture Radar (SAR) in which the antenna size is synthetically increased along the platform propagation direction. The proposed method is demonstrated through laboratory experiment.

A method for overcoming the optical diffraction limit is presented. The method includes a two-step process: optical phase retrieval using iterative Gerchberg-Saxton algorithm, and imaging system shifting followed by repetition of the first step. A synthetically increased lens aperture is generated along the direction of movement, yielding higher imaging resolution.

时间复用超解析技术成像的运动平台

We propose a method for increasing the resolution of an object and overcoming the diffraction limit of an optical system installed on top of a moving ...

科研

工程学

Measuring and Mapping Patterns of Soil Erosion and Deposition Related to Soil Carbonate Concentrations Under Agricultural Management

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonate (CaCO3) profiles. The objective is to describe a simple conceptual model and detailed protocol for repeatable field and laboratory measurements of these quantities. Here, accurate elevation is measured using a ground-based differential global positioning system (GPS); other data acquisition methods could be applied to the same basic method. Soil samples are collected from prescribed depth intervals and analyzed in the lab using an efficient and precise modified pressure-calcimeter method for quantitative analysis of inorganic carbon concentration. Standard statistical methods are applied to point data, and representative results show significant correlations between changes in soil surface layer CaCO3 and changes in elevation consistent with the conceptual model; CaCO3 generally decreased in depositional areas and increased in erosional areas. Maps are derived from point measurements of elevation and soil CaCO3 to aid analyses. A map of erosional and depositional patterns at the study site, a rain-fed winter wheat field cropped in alternating wheat-fallow strips, shows the interacting effects of water and wind erosion affected by management and topography. Alternative sampling methods and depth intervals are discussed and recommended for future work relating soil erosion and deposition to soil CaCO3.

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonates. Repeatable methods for field and laboratory measurements of these quantities and data analysis methods are described here.

农业经营条件下土壤侵蚀和沉积与土壤碳酸盐浓度关系的测量与制图

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes ...

环境科学

Ground-level Unmanned Aerial System Imagery Coupled with Spatially Balanced Sampling and Route Optimization to Monitor Rangeland Vegetation

Rangeland ecosystems cover 3.6 billion hectares globally with 239 million hectares located in the United States. These ecosystems are critical for maintaining global ecosystem services. Monitoring vegetation in these ecosystems is required to assess rangeland health, to gauge habitat suitability for wildlife and domestic livestock, to combat invasive weeds, and to elucidate temporal environmental changes. Although rangeland ecosystems cover vast areas, traditional monitoring techniques are often time-consuming and cost-inefficient, subject to high observer bias, and often lack adequate spatial information. Image-based vegetation monitoring is faster, produces permanent records (i.e., images), may result in reduced observer bias, and inherently includes adequate spatial information. Spatially balanced sampling designs are beneficial in monitoring natural resources. A protocol is presented for implementing a spatially balanced sampling design known as balanced acceptance sampling (BAS), with imagery acquired from ground-level cameras and unmanned aerial systems (UAS). A route optimization algorithm is used in addition to solve the &#8216;travelling salesperson problem&#8217; (TSP) to increase time and cost efficiency. While UAS images can be acquired 2&#8211;3x faster than handheld images, both types of images are similar to each other in terms of accuracy and precision. Lastly, the pros and cons of each method are discussed and examples of potential applications for these methods in other ecosystems are provided.

<meta charset="utf8"></head><body>地面无人机系统图像与空间平衡采样和路线优化相结合，以监测牧场植被

The protocol presented in this paper utilizes route optimization, balanced acceptance sampling, and ground-level and unmanned aircraft system (UAS) imagery to efficiently monitor vegetation in rangeland ecosystems. Results from images obtained from ground-level and UAS methods are compared.

地面无人机系统图像与空间平衡采样和路线优化相结合，以监测牧场植被

Rangeland ecosystems cover 3.6 billion hectares globally with 239 million hectares located in the United States. These ecosystems are critical for ...

In Situ Soil Moisture Sensors in Undisturbed Soils

Soil moisture directly affects operational hydrology, food security, ecosystem services, and the climate system. However, the adoption of soil moisture data has been slow due to inconsistent data collection, poor standardization, and typically short record duration. Soil moisture, or quantitatively volumetric soil water content (SWC), is measured using buried, in situ sensors that infer SWC from an electromagnetic response. This signal can vary considerably with local site conditions such as clay content and mineralogy, soil salinity or bulk electrical conductivity, and soil temperature; each of these can have varying impacts depending on the sensor technology.
Furthermore, poor soil contact and sensor degradation can affect the quality of these readings over time. Unlike more traditional environmental sensors, there are no accepted standards, maintenance practices, or quality controls for SWC data. As such, SWC is a challenging measurement for many environmental monitoring networks to implement. Here, we attempt to establish a community-based standard of practice for in situ SWC sensors so that future research and applications have consistent guidance on site selection, sensor installation, data interpretation, and long-term maintenance of monitoring stations.
The videography focuses on a multi-agency consensus of best-practices and recommendations for the installation of in situ SWC sensors. This paper presents an overview of this protocol along with the various steps essential for high-quality and long-term SWC data collection. This protocol will be of use to scientists and engineers hoping to deploy a single station or an entire network.

In Situ Soil Moisture Sensors in Undisturbed Soils

The determination of soil water content is a critical mission requirement for many state and federal agencies. This protocol synthesizes multi-agency efforts to measure soil water content using buried in situ sensors.

原位 未受干扰土壤中的土壤湿度传感器

Soil moisture directly affects operational hydrology, food security, ecosystem services, and the climate system. However, the adoption of soil moisture ...

Measuring the Structure, Composition, and Change of Underwater Environments with Large-area Imaging

Digital imaging and processing technology have evolved to facilitate the expansion of large-area imaging surveys, which increase our capacity to study the status, trends, and dynamics of organisms living in subtidal habitats. By creating photo-realistic digital twins for ex situ analyses, these approaches allow small field teams to collect substantially more data than was previously possible. Here we present a four-step, large-area imaging survey pipeline and analysis methodology, including image collection, model construction, ecological analysis, and data curation, that has been developed and refined through experimentation over the past decade. Each step described has a consistent focus on the unique value of the original source imagery. While types of data extracted from large-area image surveys are vast, we include here workflows to extract ecological data for structural complexity, community composition, and demographic analyses valuable for monitoring and hypothesis-driven efforts. We additionally include recommendations for metadata standards, which complement the collection of large-area imaging data and support archival efforts facilitating transparency and collaboration between research groups.

This protocol covers a four-step large-area imaging survey methodology used to extract metrics of structural complexity, community composition, and population demographics for coral reef communities. The quality of imagery collected and integrated access to the source imagery are prioritized within each step of the protocol.

用大面积成像测量水下环境的结构、组成和变化

Digital imaging and processing technology have evolved to facilitate the expansion of large-area imaging surveys, which increase our capacity to study the ...

Evaluation of an Exclusive Spur Dike U-Turn Design with Radar-Collected Data and Simulation

Traditional U-turn designs can improve operational features obviously, while U-turn diversions and merge segments still cause traffic congestion, conflicts, and delays. An exclusive spur dike U-turn lane design (ESUL) is proposed here to solve the disadvantages of traditional U-turn designs. To evaluate the operation performance of ESUL, a traffic simulation protocol is needed. The whole simulation process includes five steps: data collection, data analysis, simulation model build, simulation calibration, and sensitive analysis. Data collection and simulation model build are two critical steps and are described later in greater detail. Three indexes (travel time, delay, and number of stops) are commonly used in the evaluation, and other parameters can be measured from the simulation according to experimental needs. The results show that the ESUL significantly diminishes the disadvantages of traditional U-turn designs. The simulation can be applied to solve microscopic traffic problems, such as in single or several adjacent intersections or short segments. This method is not suitable for larger scale road networks or evaluations without data collection.

This protocol describes the process of solving a microscopic traffic problem with simulation. The whole process contains a detailed description of data collection, data analysis, simulation model build, simulation calibration, and sensitive analysis. Modifications and troubleshooting of the method are also discussed.

利用雷达采集的数据和仿真评估独家刺堤 U 型转弯设计

Traditional U-turn designs can improve operational features obviously, while U-turn diversions and merge segments still cause traffic congestion, ...

Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface

In recent years there has been a renewed interest in returning to the Moon for reasons both scientific and exploratory in nature. The Moon provides the perfect training ground for building large scale bases that one may apply to other planets like Mars. The existence of a radio quiet zone on the lunar far side has promise for early universe studies and exoplanet searches, while the near side provides a stable base that may be used to observe low frequency emissions from Earth&#8217;s magnetosphere that may help gauge its response to incoming space weather. The construction of a large-scale radio array would provide large scientific returns as well as acting as a test of humanity&#8217;s ability to build structures on other planets. This work focuses on simulating the response of small to large-scale radio arrays on the Moon consisting of hundreds or thousands of antennas. The response of the array is dependent on the structure of the emission along with the configuration and sensitivity of the array. A set of locations are selected for the simulated radio receivers, using Digital Elevation Models from the Lunar Orbiter Laser Altimeter instrument on Lunar Reconnaissance Orbiter to characterize the elevation of the receiver locations. A custom Common Astronomy Software Applications code is described and used to process the data from the simulated receivers, aligning the lunar and sky coordinate frames using SPICE to ensure the proper projections are used for imaging. This simulation framework is useful for iterating array design for imaging any given scientific target in a small field of view. This framework does not currently support all sky imaging.

A simulation framework for testing the imaging capabilities of large-scale radio arrays on the lunar surface is presented. Major noise components are discussed, and a software pipeline is walked through with details on how to customize it for novel scientific uses.

模拟月球表面大规模无线电阵列的成像

In recent years there has been a renewed interest in returning to the Moon for reasons both scientific and exploratory in nature. The Moon provides the ...

Continuous-Wave Propagation Channel-Sounding Measurement System - Testing, Verification, and Measurements

Channel sounders are used to measure channel characteristics for radio systems. There are several types of channel sounders used today: continuous-wave (CW), direct pulse, frequency domain using a vector network analyzer (VNA), correlation-based, and swept-time delay cross-correlator. Each of these has unique advantages and disadvantages. CW systems have a larger dynamic range than other systems with a signal that can propagate further into the environment. As the audio sampling rates allow smaller file sizes than other systems, data collection can be continuous and last for several hours. This article discusses a CW-channel sounder system, which has been used to make numerous propagation loss measurements in various cities in the United States of America. Such propagation measurements should be accurate, reproducible, and free of artifacts or biases. This article shows how to set up the measurement, how to validate and verify that the system is making reliable measurements, and finally, it shows results from some of the measurement campaigns such as repeatability measurements, clutter loss measurements (where clutter loss is defined as the excess loss from free-space transmission loss), and reciprocity measurements.

This report describes the setup, validation and verification, and results from propagation measurements using a continuous-wave, radio frequency channel-sounding measurement system.

连续波传播信道探测测量系统 - 测试、验证和测量

Channel sounders are used to measure channel characteristics for radio systems. There are several types of channel sounders used today: continuous-wave ...

A Protocol for Real-time 3D Single Particle Tracking

Real-time three-dimensional single particle tracking (RT-3D-SPT) has the potential to shed light on fast, 3D processes in cellular systems. Although various RT-3D-SPT methods have been put forward in recent years, tracking high speed 3D diffusing particles at low photon count rates remains a challenge. Moreover, RT-3D-SPT setups are generally complex and difficult to implement, limiting their widespread application to biological problems. This protocol presents a RT-3D-SPT system named 3D Dynamic Photon Localization Tracking (3D-DyPLoT), which can track particles with high diffusive speed (up to 20 &#181;m2/s) at low photon count rates (down to 10 kHz). 3D-DyPLoT employs a 2D electro-optic deflector (2D-EOD) and a tunable acoustic gradient (TAG) lens to drive a single focused laser spot dynamically in 3D. Combined with an optimized position estimation algorithm, 3D-DyPLoT can lock onto single particles with high tracking speed and high localization precision. Owing to the single excitation and single detection path layout, 3D-DyPLoT is robust and easy to set up. This protocol discusses how to build 3D-DyPLoT step by step. First, the optical layout is described. Next, the system is calibrated and optimized by raster scanning a 190 nm fluorescent bead with the piezoelectric nanopositioner. Finally, to demonstrate real-time 3D tracking ability, 110 nm fluorescent beads are tracked in water.

This protocol details the construction and operation of a real-time 3D single particle tracking microscope capable of tracking nanoscale fluorescent probes at high diffusive speeds and low photon count rates.

一种实时3D 单粒子跟踪协议

Real-time three-dimensional single particle tracking (RT-3D-SPT) has the potential to shed light on fast, 3D processes in cellular systems. Although ...

利用阵列天线探地雷达采集的时移多偏移收集跟踪入渗前深度

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利用雷达采集的数据和仿真评估独家刺堤 U 型转弯设计

模拟月球表面大规模无线电阵列的成像

连续波传播信道探测测量系统 - 测试、验证和测量

一种实时3D 单粒子跟踪协议

利用阵列天线探地雷达采集的时移多偏移收集跟踪入渗前深度

摘要

探索更多视频

时间复用超解析技术成像的运动平台

农业经营条件下土壤侵蚀和沉积与土壤碳酸盐浓度关系的测量与制图

地面无人机系统图像与空间平衡采样和路线优化相结合，以监测牧场植被

地面无人机系统图像与空间平衡采样和路线优化相结合，以监测牧场植被

原位 未受干扰土壤中的土壤湿度传感器

用大面积成像测量水下环境的结构、组成和变化

利用雷达采集的数据和仿真评估独家刺堤 U 型转弯设计

模拟月球表面大规模无线电阵列的成像

连续波传播信道探测测量系统 - 测试、验证和测量

一种实时3D 单粒子跟踪协议

原位未受干扰土壤中的土壤湿度传感器