Augmenting GPS with Pseudolites for Deformation Monitoring in Harsh Environments

摘要

Deformation monitoring projects that utilize GPS cannot always provide position updates due to harsh environmental conditions. For example, open-pit mines, large dams and urban settings all have obstructions that limit satellite visibility, which in turn limits achievable accuracy and frequency of position updates. For the past decade or so, the use of pseudolites (PLs) has been advocated to overcome this problem. Much has been done in the way of theoretical analysis and simulations to demonstrate the potential benefits of PLs, but few realworld examples of deformation monitoring using PLs exist. rnIn an effort to demonstrate the practical use of PLs for high-precision deformation monitoring, data were collected in a large open-pit mine in western Canada. Additionally, a displacement test was performed to determine if PLs aid in quicker displacement detection. Both data sets were processed using a unique approach that employs triple-differenced carrier phase measurements in a delayed-state Kalman filter. rnDespite encountering several practical issues that need to be addressed with the implementation of a PL system, sufficient data were collected to demonstrate that PLs can be used in harsh environments to provide a) more frequent solution updates, b) quicker filter convergence and c) quicker displacement detection than could normally be achieved using stand-alone GPS. PLs can be a valuable augmentation device for GPS-based deformation systems where expedient information is critical for human safety