ABSTRACT

Cut-to-length harvesters collect detailed information on the dimensions and characteristics of individual harvested trees. When equipped with global navigation satellite system (GNSS) receivers and motion sensors, the obtained measurements can be linked to locations of single harvested trees, benefitting a range of forest inventory applications. We propose a way of georeferencing harvested trees using a Komatsu 931XC harvester, which measures and records the machine's bearing, crane angle and crane length for each harvested tree. We replaced the harvester’s standard GNSS receiver with a dual-antenna differential GNSS receiver. From the coordinates obtained, rotations calculated from the GNSS receiver and data on crane length, we determined the location of 285 trees harvested in eight final fellings in Norway. We compared the obtained locations to control measurements taken on the corresponding stumps directly after harvest using a differential GNSS receiver. The mean distance between planimetric coordinates of trees measured by the harvester and corresponding control measurements was 0.88 m with a standard deviation of 0.38 m. By correcting the crane lengths for systematic deviations between harvester and control locations, the mean distance was reduced to 0.79 m. This study shows that measurements of single harvested trees can be georeferenced with sub-meter accuracy, by mounting a differential GNSS receiver on a harvester and without installing additional sensors. The results also suggest that the positional accuracy can be further improved by measuring and recording the length of the telescopic boom, and that with minor adjustments, the system could be fully automated.

摘要

定长收割机收集有关单个采伐树木的尺寸和特征的详细信息。当配备全球导航卫星系统 (GNSS) 接收器和运动传感器时，所获得的测量结果可以与单一采伐树木的位置相关联，从而使一系列森林清查应用受益。我们提出了一种使用 Komatsu 931XC 收割机对收获的树木进行地理配准的方法，该方法可以测量并记录每棵收获的树木的机器轴承、起重机角度和起重机长度。我们用双天线差分 GNSS 接收器替换了收割机的标准 GNSS 接收器。根据获得的坐标、从 GNSS 接收器计算的旋转和起重机长度数据，我们确定了在挪威 8 次最终砍伐中收获的 285 棵树的位置。我们将获得的位置与使用差分 GNSS 接收器在收获后直接在相应树桩上进行的控制测量进行比较。收割机测量的树木平面坐标与相应控制测量值之间的平均距离为 0.88 m，标准偏差为 0.38 m。通过针对收割机和控制位置之间的系统偏差校正起重机长度，平均距离减少到 0.79 m。这项研究表明，通过在收割机上安装差分 GNSS 接收器而不安装额外的传感器，可以以亚米级精度对单个收获的树木进行测量。结果还表明，通过测量和记录伸缩臂的长度，可以进一步提高定位精度，只要稍作调整，