DGPS, RTK-GPS and StarFire DGPS Performance Under Tree Shading Environments

In this paper we present our experimental measurement results using GPS in outdoor tall obstacle free and under tree shading environments. We tested and compared three different GPS receivers using different principles such as Differential GPS, Real Time Kinematic GPS and an innovative system called StarFire DGPS. Coordinate conversion issue is discussed and stationary and moving tests were performed. In the stationary tests, off-line post-processed data was used to compare the difference between receivers measuring the same point at different times. Finally three GPS receivers were mounted on a mobile platform to perform moving experiments simultaneously at open field and under tree foliage where experimental measurements show the performance of each GPS receiver according to its measurement principle in harsh conditions.