Temporal Analysis of GDOP to Quantify the Benefits of GPS and GLONASS Combination on Satellite Geometry

Claudio Meneghini,Claudio Parente

doi:10.14569/ijacsa.2020.0110370

Abstract

Global Navigation Satellite Systems (GNSS) have developed rapidly over the last few years. At present, there are GNSS receivers that combine satellites from two or more different constellations. The geometry of the satellites in relation to the receiver location, i.e. how nearly or distantly they are disposed in the sky, impacts on the quality of the survey, which is essential to achieve the highest level of position accuracy. A dimensionless number identified as Geometric Dilution of Precision (GDOP) is used to represent the efficiency of the satellite distribution and can be easy calculated for each location and time using satellite ephemeris. This paper quantifies the influence of multi-GNSS constellation, in particular GPS (Global Positioning System) and GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema) combination, on satellite geometry considering a precise period. A new index named Temporal Variability of Geometric Dilution of Precision (TVGDOP) is proposed and analyzed in different scenarios (different cut-off angles as well as real obstacles such as terrain morphology and buildings). The new index is calculated for each of the two satellite systems (GPS and GLONASS) as well as for their integration. The TVGDOP values enable the three cases to be compared and permit to quantify the benefits of GNSS integration on satellite geometry. The results confirm the efficiency of the proposed index to highlight the better performance of combination GPS+GLONASS especially in presence of obstacles.

Highlights

Satellite constellations were designed to provide threedimensional navigation by determining the position of a receiver on land, at sea, or in space [1]
This paper aimed to quantify the impact of the integration of Global Positioning System (GPS) and GLONASS systems on satellite geometry
It presents the latest results obtained within a project carried out at Department of Sciences and Technologies (DiST) of the University of Naples “Parthenope”

Summary

INTRODUCTION

Satellite constellations were designed to provide threedimensional navigation by determining the position of a receiver on land, at sea, or in space [1]. Various techniques can be used to limit distance errors, but satellite geometry is essential to achieve the highest level of position accuracy. This geometry is often expressed using a numerical measure named “Dilution of Precision”, or DOP. Sometimes satellite geometry can be inadequate even when four or more satellites of the same system are available In such situations, the GNSS (Global Navigation Satellite Systems) multi-constellation approach is useful to increment the number of visible satellite, perform their geometry, and improve the continuity and reliability of the positioning. Combining GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema) and GPS constellations, permits to achieve accessibility to a greater number of satellites in urban canyons, and better accuracy in zones of minimal availability [9].

THEORETICAL BACKGROUND

Dilution of Precision

Results and Discussion

Findings

CONCLUSION