Abstract: The present disclosure discloses a time service and positioning network system for an underground chain-shaped large space in a coal mine. The system adopts a base station-level network internal time synchronization method which takes an optical fiber time service as a main part and takes a satellite time service as an auxiliary part to construct a time service and positioning network system with an unified time within the ad-hoc network base stations, based on the ad-hoc network base stations linearly arranged in the underground chain-shaped large space in the coal mine. Through the network construction, the network stabilization and the network application, the system unifies the time reference of the base station-level network and improves the positioning accuracy of the network application by utilization of the base station-level network internal time synchronization method.

Abstract: The present disclosure discloses a time service and positioning network system for an underground chain-shaped large space in a coal mine. The system adopts a base station-level network internal time synchronization method which takes an optical fiber time service as a main part and takes a satellite time service as an auxiliary part to construct a time service and positioning network system with an unified time within the ad-hoc network base stations, based on the ad-hoc network base stations linearly arranged in the underground chain-shaped large space in the coal mine. Through the network construction, the network stabilization and the network application, the system unifies the time reference of the base station-level network and improves the positioning accuracy of the network application by utilization of the base station-level network internal time synchronization method.

Abstract: A dip angle-steering median filtering method based on a niche differential evolution algorithm, comprising the following steps: dividing a data to be processed into a series of overlapping time-space windows; obtaining an event energy curve in a time-space window and obtaining an event position according to a local maximum value of the event energy curve; obtaining event dip angles and coherence values of the event dip angles through the niche differential evolution algorithm at the event position; filtering the event dip angles according to the event dip angles and the coherence values of the event dip angles; and performing a median filtering sequentially along a filtering dip angle. The disclosure can simultaneously obtain all dip angles of intersecting events and a true three-dimensional feature enable the present disclosure to obtain a better filtering effect.

Abstract: A dip angle-steering median filtering method based on a niche differential evolution algorithm, comprising the following steps: dividing a data to be processed into a series of overlapping time-space windows; obtaining an event energy curve in a time-space window and obtaining an event position according to a local maximum value of the event energy curve; obtaining event dip angles and coherence values of the event dip angles through the niche differential evolution algorithm at the event position; filtering the event dip angles according to the event dip angles and the coherence values of the event dip angles; and performing a median filtering sequentially along a filtering dip angle. The disclosure can simultaneously obtain all dip angles of intersecting events and a true three-dimensional feature enable the present disclosure to obtain a better filtering effect.