Accuracy and time to first fix using consumer-grade GPS receivers

The primary objectives in this study were to measure time to first fix values and analyze the accuracy of the first fix coordinates of consumer-grade GPS receivers. Three different test surroundings were selected: the open sky, semi-urban and urban environments, which were tested with three GPS receivers. In addition, assisted GPS performance and the effect of A-GPS on the TTFF was tested with two different receivers. The accuracy of the first fix and time to first fix was determined by the results of these measurements. Based on the results, the impact of the surroundings and devices on position accuracy and start-up times was determined. In start-up times without assisting no remarkable differences were observed between GPS receivers. However, the observed accuracy of the first fix between the most and least accurate receiver was significant.