Multipath effects are mostly regarded as a nuisance in Global Navigation Satellite System (GNSS)
receiver measurements and it is of utmost relevance to expose the magnitude this error has on
observations. The impact of multipath is characterized in the context of a given environment and
application. In Malawi, Zomba geodynamics Continuously Operating Reference Station (CORS) is
in a multipath prone environment. The GNSS observations for this station have been used in
geodynamics studies in Malawi without an understanding of multipath affecting the positioning
accuracy. Taking this as an advantage, this paper evaluated pseudorange multipath (MP) and signal
noise ratio (SNR) on both L1 (MP1 and SNR1) and L2 (MP2 and SNR2) for the station. This was
specifically addressed by computing the elevation mask with minimum and maximum multipath
effects. In addition, the number of satellite vehicles (SVs) and their associated Geometric Dilution of
Precision (GDOP) are also determined to define their relationship with respect to elevation angles.
One week GNSS observations spanning a twenty-four hour interval for DOY 001 to DOY 007 in
January 2018 were analysed in Translation Editing and Quality Check (TEQC) software at four
(10º, 15º, 20º and 25º) cut-off angles. Results indicate high multipath effects for both MP1 and MP2
at 10º elevation mask among the four elevation masks. The least MP1 and MP2 multipath effects were
detected at an elevation angle of 25º. In addition, MP1 multipath was worse than MP2 all the angles.
Moreover, statistical results demonstrated an increase in both SNR1 and SNR2 with respect to
elevation angle. For these days, L2 signal was more affected by noise than L1. Further to this, an
assessment of SVs and GDOP for the CORS show that at least ten (10) satellites were observed in
each day at 10º and 15º elevation cut-off. The number of satellites dropped to five (5) at the elevation
angle of 25º resulting into a larger GDOP value of 4.5 (a decrease by about 38% from 1.7 at 10º and
15º elevation cut-off angles). Therefore, to increase both the number of satellites and precision,
Zomba CORS may be upgraded to a multi-constellation CORS by including other navigation systems
such as GLONASS, Galileo and BeiDou. While it is possible to reject GNSS satellite observations
below the horizon, it is recommended that post-processing of GNSS data for Zomba geodynamics
CORS be done at elevation masks above 15º. Considering that multipath repeats itself every sidereal 2
day, it is thus recommended to model or remove multipath affecting Zomba geodynamics CORS. In
addition, the study also recommends that trees very close to Zomba CORS antenna be removed to
reduce signal scattering.