Measurement of displacement of a beam due to motor step on the backscattermeter at LAPP

These gwf files can be read with lalsuite or Fr. Each file contains "V1:Camera_Scatter_FitPosY" and "V1:Camera_Scatter_FitPosX" channels, corresponding to the center of a gaussian fit in X and in Y respectively (camera axis are inverted). This can be used in conjunction with a public code. Each filename is formatted as follows: snail_N{number of point between the border and the center}_S{reference axis}{reference direction}{number of steps for this reference}[_old]_{id}-{GPS time}-{duration in second}.gwf Where "reference axis" can be "X" or "Y" and "reference direction" can be "p" (positive) or "n" (negative). These reference metadata is used to get the number of steps associated to each direction and axis using tables. The number of step done by the motor in one direction is given by the formula $\lfloor { { \frac { {f}_{a} } { {f}_{r} } } \cdot { n_{r} } } \rceil$ where $f_a$ is the factor associated to the wanted tuple (axis, direction), $f_r$ is the factor associated to the reference tuple (axis, direction) and $n_r$ the number of step done in the reference direction. If the [_old] part is present, the table to use is: name direction axis factor i + X 1.00 (ref) j - X 0.90 k + Y 1.95 l - Y 1.19 if the [_old] part is NOT present, the table to use is: name direction axis factor i + X 1.00 (ref) j - X 0.90 k + Y 1.95 l - Y 1.40 For Syp100, this will give $\lfloor {\frac{ 1 } {1.95} \cdot { 100} } \rceil = 51$ steps in X+, $\lfloor {\frac{0.90}{1.95} \cdot {100} } \rceil = 46$ steps in X-, 100 steps in Y+ and $\lfloor { { \frac { 1.40 } { 1.95 } } \cdot { 100 } } \rceil = 72$ steps in Y-.本数据集包含的GWF格式文件可通过LALSuite或Fr工具读取。每个文件均包含`V1:Camera_Scatter_FitPosY`与`V1:Camera_Scatter_FitPosX`两个数据通道，分别对应高斯拟合在X轴与Y轴上的中心位置（注：此处相机坐标轴存在反转）。该数据集可配合公开代码开展后续分析。 每个文件的命名格式如下： `snail_N{边界与中心间的点数}_S{参考轴}{参考方向}{该参考轴下的步数}[_old]_{id}-{GPS时间}-{时长（秒）}.gwf` 其中，「参考轴」可取值为`X`或`Y`，「参考方向」可取值为`p`（正方向）或`n`（负方向）。 可通过上述参考元数据结合查表法，获取各轴与各方向对应的电机步数。单方向电机的实际步数可通过以下公式计算： $$leftlfloor frac{f_a}{f_r} cdot n_r ight ceil$$ 其中，$f_a$为目标轴与方向组合对应的系数，$f_r$为参考轴与方向组合对应的系数，$n_r$为参考方向下的电机步数。 若文件名包含`[_old]`后缀，则需使用以下系数表： | 名称 | 运动方向 | 坐标轴 | 系数 | |------|----------|--------|------| | i | + | X | 1.00（参考值） | | j | - | X | 0.90 | | k | + | Y | 1.95 | | l | - | Y | 1.19 | 若文件名不含`[_old]`后缀，则需使用以下系数表： | 名称 | 运动方向 | 坐标轴 | 系数 | |------|----------|--------|------| | i | + | X | 1.00（参考值） | | j | - | X | 0.90 | | k | + | Y | 1.95 | | l | - | Y | 1.40 | 以Syp100为例，通过计算可得：X正方向步数为$$leftlfloor frac{1}{1.95} cdot 100 ight ceil = 51$$，X负方向步数为$$leftlfloor frac{0.90}{1.95} cdot 100 ight ceil = 46$$，Y正方向步数为100，Y负方向步数为$$leftlfloor frac{1.40}{1.95} cdot 100 ight ceil =72$$。