Evaluating PDOP in Multi-GNSS Environment

Abstract

Hybrid operation with two or more Global Navigation Satellite Systems (GNSS) together with (Multi-GNSS) is now popular in the enhanced Signal-in-Space (SiS) scenario that is expected to provide several advantages. The accuracy of solution using GNSS is affected by satellite geometry, quantitatively expressed in terms of Dilution of Precision (DOP) parameters. DOP values indicate the impact of the spatial distribution of the satellites on the final accuracy of the position solution. Evaluation of Position Dilution of Precision (PDOP) is important for the optimum selection of visible satellites of an individual or combined constellation to obtain good accuracy in 3-dimensioanl (3d) position fix. A proposed formulation, to evaluate PDOP in GPS-only environment with 4 satellites using the knowledge of elevation and azimuth of satellites, has been modified here to accommodate Multi-GNSS satellite availability without having any restriction on the number of satellites used for the calculation. Computed PDOP values using this algorithm match well with the data from the GNSS receivers that suggests the appropriate applicability of the algorithm for any constellation combination. Results on the optimum number of satellites for the best satellite geometry are also presented here that shows 23–25 GNSS satellites provide saturated PDOP values below 1, the addition of more satellites does not improve PDOP much.

KEYWORDS:

• DOP
• GNSS
• Look angles
• PDOP

Acknowledgment

Author AB acknowledges Space Application Centre, Indian Space Research Organization (SAC, ISRO), for providing the IGS receiver used in this study.

Additional information

Funding

This work was supported by the Defence Research and Development Organisation [grant number ERIP/ER/DG-MSS/990516601/M/01].

Notes on contributors

Pratibha Verma

Pratibha Verma received her BTech degree in the Department of Electronics and Communication Engineering from RCC Institute of Information Technology in 2015 and MTech degree in communication engineering in the department of Electronics and Communication Engineering from National Institute of Technology Agartala in 2017 in India. She continued her senior research fellowship for one year from The University of Burdwan. Currently, she is working as adhoc faculty in NIT Andhra Pradesh, India. Her research interest includes global navigation satellite system (GNSS).Email: [email protected]

Keka Hajra

Keka Hajra is an assistant professor in the Department of Electronics and Communication Engineering of B C Roy Engineering College, Durgapur. She received her master’s degree from the University of Burdwan and joined as faculty in 2003.Email: [email protected]

P. Banerjee

P Banerjee, FIET, SMIEEE, FIETE, FMSI, FURSI, joined National Physical Laboratory (NPL), New Delhi and had retired as senior deputy director, chief scientist. Then he served as professor in the Department of Electronics and Communication Engineering, Amity University, NOIDA. Currently, he is visiting faculty in Burdwan University. He has more than 40 years’ experience in the design and development of analog and digital circuits, microprocessors-based system, electronic instrumentations, phase lock system, time dissemination techniques via geostationary satellite, GPS, GLONASS and GNSS system and generation of time scale etc. He was a member of Scientific Expedition to Antarctica. He was the Chairman of Commission A of International Union of Radio Science (URSI). He is a recipient of URSI Young Scientist Award, IETE Hari Ramji Toshniwal Gold Medal, Distinguished Visiting Professorship by INAE.Email: [email protected]

Anindya Bose

Anindya Bose, BSc, MSc, MPhil, PhD, FIETE, MASI, MIGNSS, is working as a senior scientific officer in the Department of Physics, The University of Burdwan, India. His research career started at Time and Frequency Section, National Physical Laboratory (NPL), New Delhi, India. He is a recipient of URSI Young Scientist Award. His research interest includes GNSS and he leads the GNSS Laboratory Burdwan (GLB). The group is working on Multi-GNS, on efficient and cost-effective LBS development using GNSS for Indian context. The group is a member of Multi-GNSS Asia (MGA), received recognition from ESA, and have provided consultancy support to several GNSS-based Industries in India. His other research interests include microwaves communication, antennas and e-Learning. Corresponding author. Email: [email protected]