Professional Mapping Introduction

As aerial remote sensing technology has progressed and equipment manufacturing level improved, the Aerial Survey and Remote Sensing Branch purchased an inertial airborne POS system (Position and Orientation System,) including GNSS and Inertial Measurement Unit (IMU), in 2006. Fitted to an aerial photography camera, it can simultaneously record the parameters of position and posture at the moment of exposure, allowing GNSS calculation to be more precise. After testing and calibration, within a reasonable scope of precision, aerial image exterior orientation data can be quickly obtained and the aerial triangulation adjustment procedure simplified, saving time and manpower.

After the installation of the inertial airborne POS system, the main orthorectification procedure does not need to carry out the aerial triangulation process and still offers high orientation and posture precision. Hence, unless large area terrain or forest area mapping is conducted, there is no need for aerial triangulation to be carried out again, saving a substantial amount of time. A single photograph can also be matched with existing Digital Terrain Model（DTM） and digital orthorectification carried out. Therefore, when planning the annual aerial photography mission’s orthoimage production procedure, for any location, strip and block, as long as the photograph has POS orientation data on it, even if the places where photographs are taken are not continuous, orthorectification can be immediately carried out, offering great planning flexibility and mobility.