Continuous High Precision Navigation Using MEMS Inertial Sensors Aided RTK GPS for Mobile Mapping Applications

A modern mobile mapping system needs a navigation component to provide accurate geo-referencing to the imaging sensors. To achieve centimetre-level positioning accuracy RTK-GPS is a natural choice. However, RTK-GPS in urban areas suffers from frequent outages and accuracy degradation. Integration of an INS and GPS can bridge the GPS outages and maintain accuracy over short time periods. This paper describes a low-cost GPS/INS integrated system; the “NavExplorer”, which uses inexpensive MEMS inertial sensors and RTK-GPS to balance affordability and accuracy, providing a continuous, high accuracy navigation solution. By integrating NavExplorer with the PGR Ladybug panoramic camera and Multiple SICK laser scanners, a mobile mapping system has been developed for the Taipei 3D Urban Reconstruction. The NavExplorer generates position data for precise 3D object geo-referencing. The test results in Sydney and Taipei show that the NavExplorer can maintain good GPS accuracy in multipath environments, and provided smooth and continuous solutions in tunnels even when the GPS signals are completely lost.