EVALUATION OF PERFORMANCE OF GLOBAL POSITIONING SYSTEM (GPS) SPEED METERS

Abstract

In this study, Global Positioning System (GPS) simulation is used to evaluate the performance of three commercial GPS speed meters: 1) S1: SkyRC GSM020; 2) S2: XOSS G+; and 3) S3: Magene C406. It is found that with decreasing GPS signal power level, speed errors increase due to decreasing carrier-to-noise density (C/N0) levels for GPS satellites tracked by the receiver, which is the ratio of received GPS signal power level to noise density. In addition, varying speed error patterns are observed for the each of the readings. This is due to the GPS satellite constellation being dynamic, causing varying GPS satellite geometry over location and time, resulting in GPS accuracy being location / time dependent It is found that the R3 receiver provided the lowest position errors for both the open area and obstruction area scenarios due to it having higher receiver sensitivity and lower receiver noise, which allows it track higher C/N0 levels for the available GPS satellites. All three GPS speed meters are found to have relatively similar speed errors. However, Speed Meter S1 is observed to be able to operate at lower GPS signal power levels as compared to the other speed meters. This could be as it higher receiver sensitivity and lower receiver noise, which allows it track higher C/N0 levels for the available GPS satellites.
Keywords: Global Positioning System (GPS) simulation; speed measurement; Doppler shift; GPS signal power level; GPS satellite geometry.

Description