EVALUATION OF NAVIGATION SATELLITE SYSTEMS FOR FORESTRY AND ITS PRECISION IN A FOREST ENVIRONMENT

Paper in proceeding, 2012

The Swedish forestry industry is dependent of reliable positioning in the forest since much of the information in the supply chain carries positioning data. Correct coordinates are needed for the survey of the site, information of the harvesting and forwarding progress as well as positioning of road side inventory. The position data should also be able to save e.g. for planning purposes to be used throughout the forest production life-cycle. One way of providing position data is through the use of Global Navigation Satellite Systems (GNSS) where the most accurate equipment and strategies provide positions of order 1 cm accuracy in fair conditions. The GNSS equipment currently being used on the machines in the forest is however often more basic equipment that at best may provide accuracies of order 10 m under the same conditions, and often worse. In addition to the antenna, receiver and other technical equipment many factors affect the positioning quality; the forest environment itself causes uncertainty in the positioning due to tree trunk blockage of signal paths, reflections from trees, etc. Currently there are two operating GNSS systems: the American GPS and the Russian GLONASS systems. Today only GPS is being used, but with more systems emerging in the near future (e.g. the European Galileo system) the availability of satellite signals for positioning will increase significantly in the forest environment. The aim of the project is to evaluate the current accuracy of the positioning as well as compare stand-alone GPS with multiple GNSS system solutions in the forest environment. The project will also suggest techniques for improving the accuracy and robustness of the positioning suitable for the forestry field of application. The project will contribute with improvements of information flows through the whole value chain, making use of reliable positioning data. It will also provide input for ICT based systems to increase logging efficiency and minimize ground and soil impacts. Additionally, costs through misleading positioning in timber transport will be reduced and the traceability of timber and forest products will improve. The project will be ongoing during spring and finalized during the summer 2012.