Evaluating the Positional Accuracy of GPS enabled Smart Phones using RTK-GPS

Abstract

Global Positioning System (GPS) has become a potential tool for capturing positional information. This study investigates the factors that affect the accuracy of GPS receivers and how accurate the positional information obtained by smart phones. This test starts with collecting data by considering two different scenarios, open area to represent ideal conditions and build up area in AIT campus with characteristics of urban type. In the analysis it became evident that positional accuracies obtained from individual Smart phones and Hand held receiver were different in different timings of the day and in different environments. The HTC and LG Nexus5 has given accuracies around 4-7m whereas Garmin has given accuracies around 3-5m during night time and in the morning time the positional accuracies of HTC and LG Nexus5 are around 4-8m but the Garmin receiver has given highest amount of positional error i.e. around 9m. In the second analysis the accuracies of smartphones were device dependent and type of environment. The smartphones (HTC Desire, LG Nexus 5) gives better accuracies in urban type of environment than Hand held receiver (Garmin Oregon 550t). From these results the functionality of GPS in smart phones tells us we no longer need to own a standard GPS unit for navigation and in other applications which doesn’t require higher accuracies like detection of earthquakes of magnitude larger than 7, in agriculture for estimation of crop water, agriculture land management and coastal monitoring by geo-tagging the images.