Comparison of Two Approaches to GNSS Positioning Using Code Pseudoranges Generated by Smartphone Device

Massimiliano Pepe,Vincenzo Saverio Alfio,Domenica Costantino,Gabriele Vozza

doi:10.3390/app11114787

Massimiliano Pepe, Vincenzo Saverio Alfio + Show 2 more

Open Access

https://doi.org/10.3390/app11114787

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Journal: Applied sciences	Publication Date: May 23, 2021
Citations: 12	License type: CC BY 4.0

Affiliation: Polytechnic University of Bari

Abstract

The release of Android 7.0 has made raw GNSS positioning data available on smartphones and, as a result, this has allowed many experiments to be developed to evaluate the quality of GNSS positioning using mobile devices. This paper investigates the best positioning, using pseudorange measurement in the Differential Global Navigation Satellite System (DGNSS) and Single Point Positioning (SPP), obtained by smartphones. The experimental results show that SPP can be comparable to the DGNSS solution and can generally achieve an accuracy of one meter in planimetric positioning; in some conditions, an accuracy of less than one meter was achieved in the Easting coordinate. As far as altimetric positioning is concerned, it has been demonstrated that DGNSS is largely preferable to SPP. The aim of the research is to introduce a statistical method to evaluate the accuracy and precision of smartphone positioning that can be applied to any device since it is based only on the pseudoranges of the code. In order to improve the accuracy of positioning from mobile devices, two methods (Tukey and K-means) were used and applied, as they can detect and eliminate outliers in the data. Finally, the paper shows a case study on how the implementation of SPP on GIS applications for smartphones could improve citizen science experiments.

Highlights

In 2016, Google made accessible the GNSS raw measurements of smartphones and tablets running Android 7.0
In the first part of the paper, we show the app for the collection of GNSS raw data and two tools to perform Differential Global Navigation Satellite System (DGNSS) positioning and Single Point Positioning (SPP)
We present a statistical analysis method to evaluate the accuracy and precision of GNSS positioning of smartphones, using only pseudorange measurements

Summary

Introduction

In 2016, Google made accessible the GNSS raw measurements of smartphones and tablets running Android 7.0. As reported by the European GNSS Agency [1], the access to GNSS raw measurements has allowed researchers to conduct several studies for increasing the performance of commercial GNSS mounted on smartphones and tablets, mainly through post-processing techniques of measurement. An example of algorithms to improve positioning is provided by Zhang et al [4], who applied a time difference filter in GNSS kinematic positioning. The latter algorithm is divided into several steps. The GNSS measurement error is estimated through the signal-to-noise-ratio (SNR)

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