A Study on the Impact of GPS-Derived Tropospheric Delay over some Nigerian Stat

Open Access

Year : 2023 | Volume :10 | Issue : 1 | Page : 13-24
By

J.N. Nzeagwu

J.O. Urama

A.E. Chukwude

D.I. Okoh

  1. Deputy Director Technology Transfer Registration Department, National Office for Technology Acquisition and Promotion, (NOTAP) Abuja Nigeria
  2. Professor of Astrophysics Department of Physics and Astronomy, University of Nigeria Nsukka Nigeria
  3. Professor of Astrophysics Department of Physics and Astronomy, University of Nigeria Nsukka Nigeria
  4. Research Scientist Centre for Atmospheric Research, National Space Research and Development Agency Anyigba Nigeria

Abstract

The effect of GPS-derived tropospheric delay on radio propagation oversome Nigerian stations is examined. The stations are located in the African equatorial region, and include: Abuja (8.9°N, 7.4°E), Akure (7.3°N, 5.2°E), Enugu (6.5°N, 7.5°E), Lagos (6.5°N, 3.4°E), and Port Harcourt (4.8°N, 7.0°E). This is the first study in the African equatorial region that uses in-situ meteorology measurements as well as GPS satellite measurements to present the impact of tropospheric delay on radio propagation, especially with respect to varying elevation angles. Data used for the study covered the twelve-month period from January to December 2013, and the modified Hopfield model was used to derive the tropospheric delays. The results show that GPS-derived tropospheric delays vary significantly with elevation angles of the satellites. The values of the tropospheric delays are typically about 2.5 m when the radio transmission path is at around 90° of elevation, and the values increase to over 20 m when the radio transmission is at around 10° of elevation. The rate of change of the tropospheric delay (with respect to elevation angle) increases with decreasing elevation angle. The tropospheric delay typically increases by about 3% when the elevation angle changes from 90° to 80°, and by about 60% when the elevation angle changes from 20° to 10°. Time-dependent maps of the tropospheric delay reveals a pattern which indicates that variation of the tropospheric delay is significantly controlled by elevation angles of the Global Positioning System (GPS) satellites.

Keywords: Tropospheric delay, GPS, meteorology, elevation angle, radio propagation.

[This article belongs to Research & Reviews : Journal of Space Science & Technology(rrjosst)]

How to cite this article: J.N. Nzeagwu, J.O. Urama, A.E. Chukwude, D.I. Okoh. A Study on the Impact of GPS-Derived Tropospheric Delay over some Nigerian Stat. Research & Reviews : Journal of Space Science & Technology. 2023; 10(1):13-24.
How to cite this URL: J.N. Nzeagwu, J.O. Urama, A.E. Chukwude, D.I. Okoh. A Study on the Impact of GPS-Derived Tropospheric Delay over some Nigerian Stat. Research & Reviews : Journal of Space Science & Technology. 2023; 10(1):13-24. Available from: https://journals.stmjournals.com/rrjosst/article=2023/view=91898

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Regular Issue Open Access Article
Volume 10
Issue 1
Received January 26, 2021
Accepted March 14, 2021
Published March 14, 2023
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