The use of monitoring systems to detect wall movements in surface mining has emerged in the last ten years as a standard work and safety practice. The development and optimization of remote monitoring technologies like radar interferometry have greatly contributed to the anticipation of slope movements and to the reduction of incidents and fatalities related to slope failures. The same has not happened in the underground mining industry, where deformation monitoring of openings is in most cases still demanded to contact sensors like extensometers, micro-seismic gauges, strain gauges, fiber optic systems, which can provide only point information. The new HYDRA-U (HYper Definition Radar - Underground) radar system, designed by IDS GeoRadar, is a submillimeter accuracy radar interferometer operating at MMW (MilliMeter Wave) frequency; the system is able to produce an updated radar map every 30 seconds providing both range and angular resolution by performing FMCW Arc SAR acquisitions. In this research work a HYDRA-U unit has been extensively tested to measure the monitoring performances of the system and assess the actual applicability of this radar solution as a real-time ground fall early warning system. First tests have been performed in laboratory conditions using corner reflectors to assess the performance in terms of range resolution and angular resolution. Moreover, a motorized corner reflector with a micrometric movement control has been used to estimate the accuracy of the displacement measurement. The last part of the test consists in a long-term deployment in underground mining environment. The system has been deployed in an underground mine tunnel. During the test, the HYDRA-U system clearly picked up a moving area; the analysis of the interferometric data shows an evident developing trend with marked accelerations and periods of relative steadiness, which can be correlated with the intensity of the local mining activity.
Ground Based Interferometric Radar (GBInRad) is a class of terrestrial remote sensing imaging system, based on
microwave interferometric techniques. The principal application of GBInRad system is deformation monitoring,
since respect to other techniques they can provide remote sensing, high sensitivity to small deformations, long range
of measurements, imaging capability and fast scan time.
The main limitation of standard GBInRad system is their capability of detecting movements only along the Line of Sight
(LoS) of the sensor, although actual targets may show deformations in any direction of space; this represents an
important limitation with respect to other techniques able to estimate the full 3D deformation vector.
If the displacement direction is not known a priori, combining together LoS displacement measured from different
spatial positions, it is possible to reconstruct the actual 3D displacement vector of monitored targets.
In this paper are introduced and analysed the various aspect of the displacement vector measurement with multiple
GBInRad system that work both in a monostatic and in a bistatic configuration.
In the monostatic configuration every system transmits and receives the signal independently from the others; this
approach requires multiple GBInRad system deployed to monitoring the same scenario and therefore its main
limitations lie in the costs, power consumption and maintenance.
A possible cost-effective evolution of the monostatic configuration is to exploit GBInRad system in a multiple bistatic
configuration; a multiple bistatic Radar is a system in which a transmitter operates together with multiple receivers
located in different positions in space.
In this paper, the deformation vector measurement by means of bistatic GBInRad is proposed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.