Bringing GPS into harsh environments for deformation monitoring
Certain deformation monitoring environments pose severe limitations on the achievable accuracy and precision that can be attained by instrumentation used to monitor deformation behaviour. Large open pit mines are one example. In such environments, it is not uncommon for the degradation in precision of geodetic technologies to be so large that the minimum detectable displacement fails to meet the mine’s requirements for displacement detection. In order to meet these requirements, an innovative approach to deformation monitoring is required. Presented is a technique which capitalizes on the advantages of Global Positioning System (GPS) sensors to provide fully-automated and continuous subcentimetre displacement detection in real time. Software was developed which utilizes triple-differenced carrier phase observations in a Delayed-State Kalman filter to provide continuous, high precision position updates in a fully automated mode. The software was enhanced to include pseudolite processing capabilities. An interdisciplinary approach was then used to predict deformation behaviour to aid in the design of a geodetic deformation monitoring scheme. It was shown that the processing strategy employed helps to mitigate the effects of residual tropospheric delay biases. Additionally, it was illustrated that pseudolites can be used to provide more continuous position updates in harsh environment conditions. An example was also given to demonstrate how deterministic modelling can be used to predict deformation behaviour and how this information can be incorporated into the design of a geodetic deformation monitoring scheme.