# GNSS Positioning Using Mobile Devices with the Android Operating System
###### Abstract  
The access and the use of the global navigation satellite system (GNSS) pseudo-range and carrier-phase measurements mobile devices as smartphones and tablets with an Android operating system has transformed the concept of accurate positioning with mobile devices. In this work, the comparison of positioning performances obtained with a smartphone and an external mass-market GNSS receiver both in real-time and post-processing is made. Particular attention is also paid to accuracy and precision of positioning results, also analyzing the possibility of estimating the phase ambiguities as integer values (fixed positioning) that it is still challenging for mass-market devices. The precisions and accuracies obtained with the mass-market receiver were about 5 cm and 1 cm both for real-time and post-processing solutions, respectively, while those obtained with a smartphone were slightly worse (few meters in some cases) due to the noise of its measurements.  
s 2020; 9, 220010.3390/jigj9040220  
tools for positioning in a whole series of fields that do not require the performance of a geodetic receiver Relevant applications in commercials are product detection, location-based billing, location-based advertising, and proximity-based notification. In law enforcement, interesting applications are search and rescue, geofencing, crime scene recovery, and more. Other field are intelligent transport systems, health care, museum, environmental monitoring, and teaching. In this last case, the spread of these devices, together with the easy access to the API level required to store the GNSS data, could allow instructors to easily set up teaching methodologies and share knowledge in the positioning field [7].  
Many studies have already been done regarding positioning solutions [8; 9], considering GPS/GNSS chipset, and a European task force has been activated in recent years ([[https://www.gsa.europa.eu/gnss-raw-measurements-task-force](https://www.gsa.europa.eu/gnss-raw-measurements-task-force)]([https://www.gsa.europa.eu/gnss-raw-measurements-task-force](https://www.gsa.europa.eu/gnss-raw-measurements-task-force))).  
However, this paper presents the performances of two smartphones (Huawei P10+ and Samsung Galaxy S8+) with the Android operating system compared to those obtainable with another mass-market GNSS receiver (u-blox NEO M8T), with the same characteristics of the smartphones, equipped with a patch antenna.  
To reach the goal previously described, the authors have conducted many outdoor tests, considering the two main positioning approaches (static and kinematic) under different conditions in terms of multipath effects and number of visible satellites. For making the obtained results independent by the processing algorithms, different software for obtaining post-processed positioning solutions have been used. The paper is organized as follows: after this introduction, a section related to the GNSS positioning techniques available with smartphone technology is provided. Then, the test cases and the obtained results will be shown before some comments and conclusions.