ASSESSMENT OF NEQUICK MODELAT LAGOS, NIGERIA USING GPS TEC

Abstract

Diurnal variation of vertical total electron content (VTEC) over Lagos, Nigeria (6.52
N, 3.39⁰E, dip latitude 3.03⁰ S) during low solar activity period (2010) and a
comparison with NeQuick-model-derived VTEC, are presented in this paper. VTEC
generally increases from 0600 h LT and reaches its maximum value at approximately
1400 to 1700 h LT during all months considered. Our result shows that NeQuick
model provide a good prediction during daytime and nighttime at Lagos, although
some improvements are still required in order to have increase navigational accuracy
for single frequency Global Positioning System (GPS) receivers. The pre-sunrise and
noontime deviations between modelled and observed VTEC could arise because
either the peak electron density of the F2 region (NmF2) or the shape of the electron
density profile, or both, are not well modelled.