EFFECT OF RECORDING INTERVAL ON GPS ACCURACY

Abstract

Static GPS survey technique is the most reliable applied technique for establishment of permanent reference stations and GPS network for various precise applications [1]. Differential GPS technique (DGPS) reduces most of the GPS observations errors. Moreover, numerous studies of the factors that affect GPS accuracy are accomplished by several researchers along the past years. In spite of that studies have been paid to overcome, or eliminate; to some extent; the effects of these errors, and although GPS has been studied extensively over the years, a study of the relation between the recording interval and GPS accuracy is missing. Surveyors have been dependent on the information from various sources (vendors of the GPS equipments, ambiguous guidelines by different companies and institutions, etc) as well as on their own experiences. The present work aims to study the effect of recording interval on GPS accuracy. At this study, the field experimental work has been carried out according to the static DGPS technique for a range of recording interval (1 through 60 seconds). This study has been performed within a short range of base line lengths (up to 20km [2,3 & 4]), and observation period of 40 minutes. The present work has been accomplished through five test groups taking the parameters (Base Line Length, Observing Time, PDOP and Number of Satellites in view of GPS receiver) into consideration. Accordingly, these tests are realized in form of the relation between the recording intervals and coordinates and point positional errors. The test results revealed that the GPS accuracy has an inverse positive relationship with the recording interval. The highest accuracy has been achieved at one second recording interval.