研究了在进行GPS静态绝对定位时,误差经过多长时间会稳定在一个较小的范围内.在研究过程中,先是使用手持GPS接收机分4天对某一特征点采取静态绝对定位的方法来获取实验数据,每天的定位时间为1 h,都是从上午10:00到11:00,每隔1 m in,记...研究了在进行GPS静态绝对定位时,误差经过多长时间会稳定在一个较小的范围内.在研究过程中,先是使用手持GPS接收机分4天对某一特征点采取静态绝对定位的方法来获取实验数据,每天的定位时间为1 h,都是从上午10:00到11:00,每隔1 m in,记录一次观测值,4天一共获得4组特征点的坐标.然后通过对每组坐标值求均值和标准差的方法处理数据.在对处理结果进行比较和分析后,得出随着观测时间的延长,观测值会变得更加精确,经过20 m in左右的时间,经度坐标的误差会稳定在一个较小的范围内;经过27 m in左右的时间,纬度坐标的误差会稳定在一个较小的范围内.展开更多
With deep mining of coal mines, prospecting multilayer water-filled goaf has become a new content that results from geophysical exploration in coalfields. The central loop transient electromagnetic （TEM） method is f...With deep mining of coal mines, prospecting multilayer water-filled goaf has become a new content that results from geophysical exploration in coalfields. The central loop transient electromagnetic （TEM） method is favorable for prospecting conductive layers because of the coupling relationship between its field structure and formation. However, the shielding effect of conductive overburden would not only require a longer observation time when prospecting the same depth but also weaken the anomalous response of underlying layers. Through direct time domain numerical simulation and horizontal layered earth forward modeling, this paper estimates the length of observation time required to prospect the target, and the distinguishable criterion of multilayer water-filled goal is presented with observation error according to the effect of noise on observation data. The observed emf curves from Dazigou Coal Mine, Shanxi Province can distinguish multilayer water-filled goaf. In quantitative inversion interpretation of observed curves, using electric logging data as initial parameters restrains the equivalence caused by coal formation thin layers. The deduced three-layer and two-layer water-filled goals are confirmed by the drilling hole. The result suggests that when observation time is long enough and with the anomalous situation of underlying layers being greater than the observation error, the use of the central loop TEM method to orosoect a multilaver water-filled goaf is feasible.展开更多
文摘研究了在进行GPS静态绝对定位时,误差经过多长时间会稳定在一个较小的范围内.在研究过程中,先是使用手持GPS接收机分4天对某一特征点采取静态绝对定位的方法来获取实验数据,每天的定位时间为1 h,都是从上午10:00到11:00,每隔1 m in,记录一次观测值,4天一共获得4组特征点的坐标.然后通过对每组坐标值求均值和标准差的方法处理数据.在对处理结果进行比较和分析后,得出随着观测时间的延长,观测值会变得更加精确,经过20 m in左右的时间,经度坐标的误差会稳定在一个较小的范围内;经过27 m in左右的时间,纬度坐标的误差会稳定在一个较小的范围内.
基金supported by the National Science Foundation of China(No.41374129)Science and Technology Project of Shanxi Province(No.20100321066)Research and Development Project of National Major Scientifi c Research Equipment(No.ZDYZ2012-1-05-04)
文摘With deep mining of coal mines, prospecting multilayer water-filled goaf has become a new content that results from geophysical exploration in coalfields. The central loop transient electromagnetic （TEM） method is favorable for prospecting conductive layers because of the coupling relationship between its field structure and formation. However, the shielding effect of conductive overburden would not only require a longer observation time when prospecting the same depth but also weaken the anomalous response of underlying layers. Through direct time domain numerical simulation and horizontal layered earth forward modeling, this paper estimates the length of observation time required to prospect the target, and the distinguishable criterion of multilayer water-filled goal is presented with observation error according to the effect of noise on observation data. The observed emf curves from Dazigou Coal Mine, Shanxi Province can distinguish multilayer water-filled goaf. In quantitative inversion interpretation of observed curves, using electric logging data as initial parameters restrains the equivalence caused by coal formation thin layers. The deduced three-layer and two-layer water-filled goals are confirmed by the drilling hole. The result suggests that when observation time is long enough and with the anomalous situation of underlying layers being greater than the observation error, the use of the central loop TEM method to orosoect a multilaver water-filled goaf is feasible.
