Improvement of Autonomous GPS Accuracy with the Crisscross Arrangement of Low-cost GPS Receivers

In Japan, many borders of forest ownership still have not been determined, and such undetermined borders make it difficult to construct forest roads or spur roads and to harvest trees efficiently. As a result, the Japanese forest industry is suffering from high production costs. Therefore, it is necessary and urgent to make more forest/spur roads and to reduce the production cost by determining the borders of forest ownership. The GPS is a promising tool to determine such borders more efficiently than conventional surveying methods. However, GPS receivers for surveying are still expensive for the lowprofitable Japanese forest industry. That is why low-cost GPS receivers for navigation are often used instead of high-cost ones, but the autonomous GPS accuracy is not always acceptable when low-cost GPS receivers are used for this purpose. The only solution to improve the autonomous GPS accuracy is to average the result of a long-time GPS measurement, but a longer GPS measurement clearly leads to the low efficiency of border determination with the GPS. Therefore, we propose a new technique to improve the autonomous GPS accuracy with the crisscross arrangement of five low-cost GPS receivers. The advantage of this method is to obtain five times more positioning results to be averaged for higher accuracy than the conventional method. In this study, we conducted a field test in the Sanbe University Forest, Shimane University to determine the autonomous GPS accuracy with the crisscross arrangement of low-cost GPS receivers. The results of the field test showed that the autonomous GPS accuracy was improved by averaging the measurements of five low-cost GPS receivers in crisscross arrangement.