Densification of First-Order Geodetic Controls within the University of Benin, Nigeria

Abstract

This study focused on the densification of first-order controls within the University of Benin
Ugbowo campus, using CORS_Geosystems as the virtual reference station. The evolving
developmental project within the campus necessitated the establishment of more control
points. Eight newly designated control points were designated for coordination. In addition,
one previously established control point with the ID Raph_UB_02 was re-coordinated to
validate the accuracy of the positional data collected compared to the pre-existing record. The
rover receivers' occupation time at each control point lasted at least one hour. The downloaded
data was processed and adjusted using Trimble Business Centre 2.70. The maximum 2D and
3D precisions obtained were 1:6,038,657 and 1:6,035,931 along the CORS_Geo and Raph
GNSS_05 baselines, while the minimum 2D and 3D precisions obtained were 1:4,255,886
and 1:4,256,390 along the CORS_Geo and RAPH GNSS_11 baselines. All the calculated
values for the allowable limit in the Class "A" survey for control densification had a 3D
maximum standard error of 0.011 m. These results are more accurate than the recommended
standard by the Surveyors Council of Nigeria. Thus, this study provided a piece of verifiable
evidence about the CORS_Geosystems' efficacy in providing quality positioning solutions at
higher accuracy and the suitability of the established control points on campus for various
applications. These controls are therefore recommended for precise engineering projects and
other developmental applications.