INSAR COLLABORATIVE MONITORING MODE AND MULTI-MODE COMPUTING SERVICES FOR GEOHAZARDS IDENTIFICATION IN OPEN-PIT MINING AREA

InSAR has developed a variety of methods, such as D-InSAR, PS-InSAR, MBAS, CT, SqueeSAR, POT, etc., which have been widely used in land subsidence monitoring. For open pit mining areas, there are usually mining activity, complex terrain features, low coherence, and local large deformation gradients, which makes it difficult for time series InSAR technology to obtain high-density surface deformation information in open pit mining areas. Traditional methods usually only monitor the linear deformation of the surface caused by the mining of a few working zone above the underground mining area, and the temporal and spatial resolution is lower. How to obtain high-precision, high-density, and time-sensitive deformation information is the main difficulty of InSAR monitoring in open pit mining areas. Make full use of the geosensor network monitoring system , optimize monitoring mode of collaborated satellite-to-ground based InSAR, further realize whole calculation and geographic information services, to achieve early identification and discovery of abnormal in large-area macro-monitoring, and accurate monitoring of local areas in real-time early warning, which is the development direction of ground deformation monitoring of mining areas. The study area is Pingshuo open pit mining area. we fully study the application mode and services of InSAR monitoring for geohazards in open-pit mining area, through the establishment of satellite InSAR technology system for large-scale macro-monitoring and forecasting, and GBSAR and GSN for local precision monitoring. The effective mode of InSAR monitoring of geohazard in open-pit mines is summarized. A combination of D-InSAR, POT (Pixel offset tracking), Time Series-InSAR and GB-SAR is used in a wide range, and high-resolution optical images are used to identify localized changes in subsidence areas and open-pit mining areas.


INTRODUCTION
InSAR has developed a variety of methods, such as D-InSAR, PS-InSAR[Alessandro Ferretti, Claudio Prati, andFabio Rocca, 2001 andHooper Andy, Segall P, Zebker H.A., 2007], MBAS [Francesco Casu, Mariarosaria Manzo, Antonio Pepe, and Riccardo Lanari, 2008], CT[Oscar Mora, Jordi J. Mallorqui, and Antoni Broquetas,2003], SqueeSAR, POT[Bingqian Chen, Zhenhong Li, Chen Yu, David Fairbairn, et al, 2020]  Combining GNSS and InSAR technology to measure ground deformation in the mining area, obtain ground subsidence information caused by coal mining [Dong Jiang, Jin Zhang, Zikuan Zhou, et al, 2010], and use GIS technology to comprehensively analyze the ground subsidence process and coal mining process [Francioni M, Salvini R, Stead D, et al, 2015]. it also can get the ground subsidence changes information synchronized with the coal mining process.   Time series InSAR and SBAS technology based on StaMPS are used, which compute of high-resolution SAR data for surface deformation monitoring in Pingshuo mining area. Establish a operation process and an early identification knowledge database for abnormal data and real danger, and use GIS technology to provide early warning services for ground disaster monitoring.

Collaborating InSAR with GSN Monitoring System
Collaborating satellite InSAR of large-extends surface subsidence monitoring with geosensor network monitoring system, such as ground-based SAR of high dynamic local area monitoring and GNSS precise monitoring of specific surface feature points, satellite-ground collaborative monitoring are constructed and the effectiveness of monitoring are evaluated.

Collaborating GSN with Optical Remote Sensing
Collaborating geosensor network with optical remote sensing, and the fusing computation of the observation results, additional information, or constraints relationship between the geosensor network and satellite remote sensing, the integrated monitoring and analysing system is built for mining geohazards monitoring.
By fusing high-resolution SAR image and high-resolution optical image, the location, size, boundary and other characteristics of the mining area geohazards feature object are determined, and the typical mining area geohazards inventory map is established.

Constraint Computing of Collaborating Monitoring
The Constraint computing of collaborating monitoring is the important theory and method to realize the geosensor networks collaborative monitoring and application. Taking the horizontal deformation rate calculated by the geosensor network as a constraint, the slant range deformation rate obtained by InSAR is decomposed into vertical deformation rate and horizontal deformation rate enhanced by the joint computing of satelliteground collaborative monitoring.

PS-DInSAR Monitoring Methods for Mine Subsidence
The high-resolution SAR data of surface deformation

Ground-based Interferometric Radar (GB-SAR) is a significant technique to monitor the deformation of open-pit mine side slope.
It has high sensitivity to small deformations, in the region of submillimeter to millimeters, which is achieved by exploiting the interferometric capability of centimeter-wavelength microwaves.
It is a long-range measurement device, which can work up to some kilometers. It can provide, in an automatic way, massive deformation measurements. In particular, the GB-SAR

The geo-environment characteristic Associated with disaster and spatial variation
Geosensor network collaborative monitoring fusion calculation, spatial variability and temporal-spatio evolution mechanism is the most of important scientific problem. Based on the three aspects of the basic factors, development factors and Inducing factors, the data set of the geo-environment characteristic factors of the mine disaster area is established. Based on regional high precision digital elevation model data, mine surveying data, regional surface coverage data and historical meteorological data and underground rock soil detection results of calculation and analysis, extraction mining area elevation, slope, slope type, gully density and water influence from the characteristic factor.

Monitoring
Based on OGC sensor information model and standards, the development of the Geosensor information model, realize the mutil-geosensor real-time access. Based on unified temporal and spatial datum, used multi-geosensor data fusion processing method, realize the time sequence data of the geosensor integration calculation. discovered abnormal monitoring information, and early warning system deployed and released.
All monitoring data is storied into MongoDB database. We interval which helps to analyse the deformation mechanism, process, early warning and forecasting.
An geo-infographic map is defined as a visualization of data or ideas that tries to convey complex information to an audience in a manner that can be quickly and easily understood, which is helpful to convey specific information. The knowledge and geoinfographics map are used to obtain the better application effect in the data and information visual representation of the GSN, see Figure 10.
Extract structured event knowledge from geo-infographics map, and mine the characteristics of the event in the time dimension, succession or dependency dimension. From the aspects of data features, concept description, classification, clustering, correlation analysis, association modeling, change and deviation analysis, etc., establish a semantic classification system for geoinfographics map, and associate knowledge discovery methods and sequential pattern knowledge discovery methods, etc., carry out semantic classification and analysis of multi-field geoinfographics map, and realize the standardized description, semantic structure, formalization, spatial expression and temporal-spatial relationship analysis of geohazards geoinfographics map.
The dashboard methodology of GSN represents monitoring point change information, using the calendar panel represents changes with the date of GSN data, using the block area thematic map represents early warning information. Event driven disaster warning service chain construction and early warning visualization services are main contents of geosensor network service.