EVALUATION OF HANDHELD GPS AND DGPS ACCURACY FOR PLANIMETRIC MAPPING AT NACEST, MAKURDI, BENUE STATE

Abstract

This research work evaluates the accuracy of handheld GPS and 
Differential Global Positioning System (DGPS) devices for planimetric mapping at the NACEST, North Bank Makurdi, Benue State. Planimetric mapping requires exact location data, and handheld GPS/DGPS devices are commonly used due to their portability and ease of use. However, their correctness can vary. This research investigates the accuracy of handheld GPS and DGPS devices in capturing boundary beacons at the study site. 
Data were collected using Trimble Geo 7X handheld devices and Chcnav DGPS 173 . A total of 40 boundary beacons were surveyed, and their coordinates were compared to established reference values. The northing error is 0.050% and easting error is 0.370% suggesting that handheld GPS may suffice in the absence of DGPS. Additionally, the study found significant variations in accuracy depending on satellite geometry, signal multipath, and atmospheric conditions. The findings of this study have implications for planimetric mapping and boundary demarcation applications in Nigeria. The results suggest that DGPS devices are more suitable for high-accuracy applications, while handheld GPS devices may be sufficient for lower-accuracy requirements. This research contributes to the understanding of handheld GPS/DGPS accuracy in tropical regions and informs best practices for planimetric mapping in Nigeria.