To support ground truth observation for remote sensing, a navigation system was developed by using the Real Time Kinematic/On The Fly (RTK/OTF) GPS technique with PC-based GIS. The position of an observer is displayed graphically over an digitized air photograph on a notebook type PC in real time. The distance and direction to the destination are also indicated on the PC. We used this system at Kushiro mire where there are very few landmarks to determine the position before the GPS observation. As a result a lot of observation points were determined in a short time. After observation we can use this system for various type of data management by using database function of GIS.
